The controller has five push buttons, each with a green led.
The first four buttons have images of small and large cup sizes, and a number to represent 1 or 2 shots.
Each time one of the shot buttons is pressed, the machine dispenses a pre-programmed quantity of hot water through the coffee shot. The button on the right is used manually control the flow, for instance to purge the grouphead or during cleaning operations.
Below are the steps to program the dosing on the Gaggia TD.
I am not sure what the letters TS, TE or TS stand for and I am forever mixing up the TE and TD machines, so I will say that I think they should be “Solo” for the TS (as it has a water tank and doesn’t need to be plumbed in) and “Doser” for the TD as it measures the water volme for each coffee shot. The TE can stand for whatever you like !
I owned the TS for about 5 years, and loved it. The look of the machines is a matter of taste, but they certainly have some weight to them and certainly don’t move around when you lock the portafilter into the group.
For a few years I had been searching for a TD or TE, and in early 2019 I found a TE and a Mazzer Super Jolly in Chesham, Bucks. Duly collected, following a quick chat with the seller confirming that they had been purchased new by the former homeowner and only used for the occasional dinner party. After getting the machine home and running it from a jug of water confirmed all was well. The only requirement now was to think about plumbing in the water feed.
As usual, other stuff took priority, and whilst the TE sat in the porch, a TD appeared in my searches. The information on the machine was sparse, but the purchase was made and the machine was collected from Shoreditch from a lovely Polish couple. Sadly on returning home, some troubles with the were discovered. More of that later.
So there we are. Three of a kind. You would think we would stop there, but another machine appeared. This time a Gaggia D90 . I couldn’t let that go could I ? Afterall, it was only four hours away in Halifax.
So there we have it for the moment. There aren’t going to be any more for a while. So I am told.
Whilst investigating a strange coffee leak recently, I found you can easily remove the front panel of the TS, presumably to allow changing of the heating element.
Just a couple of screws to remove and the panel comes out easily. You need to turn the power off of course, and feed the rubber hose through the panel whilst tilting the panel at quite an angle.
Here you can see the boiler, with the heating element held in by three allen screws. The red coil on the right is the overheat thermostat, which has a vial inserted into a pocket in the element.
There are three copper pipes connected to the boiler in this view. The lower one is the hot water outlet, which is connected to the hot water tap. The top one is the steam outlet connected to the steam tap. Finallly, the middle one connects to a larger tube which runs through the boiler and acts as a heat exchanger, with the pump providing high pressure cold water that runs through this tube collecting heat from the boiler and feeding the group head with high pressure hot water at about 98C. The boiler is probably at about 120C to provide the necessary steam for the wand.
Also connected to the tee for the wand is front panel pressure gauge, which normally reads around 1.5bar when the boiler is up to pressure. The final tube connected to this tee is the one to the pressure switch and air release valve. The pressure switch turns off the heating element when the boiler is up to pressure. The air release valve conversley lets air into the boiler when it cools and automatically closes when the water in the boiler reaches atmospheric boiling temperature (100C) and so the boiler vessel is sealed and can increase in pressure until the pressure switch cuts of the power to the element.
On the left, you can see the red water pump (normally an Ulka EX5 or EP5). The silicone tube on the left is relief hose from the Over-Pressure Valve (OPV), which reduces the pressure from the pump from a maximum of about 15bar down to 10bar which is better for coffee extraction. The brass nut the hose is fixed to is a mod for the black plastic elbow which is normally seen here, but is prone to breakage after time.
If you have a Gaggia TS which is only intermittently heating the water in the boiler, this is most often caused by a faulty relay in the controller.
The main other causes could be a pressure switch fault. Less likely are intermittent wiring fault, intermittent heater fault or intermittent contact of the over-temperature thermostat. These latter causes are far more likely to cause a complete failure.
This section shows tests to determine where the fault lies. You will need to be competent working inside live equipment to carry out these tests. If you are not, then replace the pressure switch, see if that cures the problem, then replace the controller.
Test 1. Confirm good measurement reference point.
We need to find an easy to identify reference point for our measurements. One of the connections to the solenoid on the group head has three wire connections, this will be our reference. With the red probe, we should measure about 230V AC on the live side of the group head heater thermostat (the side NOT connected to the group head heater).
Test 2. Check the Controller Output
Whenever the coffee machine is on, there is water in the tank, and there is water in the boiler, as measured by the controller, relay K3 inside the controller should close and provide volts tot he pressure switch.
Measure the voltage on the pressure switch microswitch terminal which connects to the controller. There should be 230V AC here for the heater to work. If you don’t see 230V, then check:
1. Water in the tank and so the red tank empty lamp will be out.
If the lamp is lit, but the tank has water in it, check the wiring of the two probes.
2. Sufficient water in the boiler (if the boiler was emptied for transit, then you may need to power the machine up several times to fully fill the boiler).
3. Boiler probe clean of scale. Remove the probe wire and touch it directly on the boiler. The controller will think the boiler is full and power up the heater. You should be able to hear the relay click.
4. None of the above. Very likely a controller fault (but read to the end of this page).
Test 3. Test the Pressure Switch
If you DO see 230V on the pressure switch, then you should also see 230V on the side of the pressure switch connected to the boiler.
If this is not the case, then the pressure switch is faulty.
Test 4 The Overtemperature Thermostat
Move your red probe to the live side of the group head heater thermostat, and check both sides of the overheat thermostat. You should see 230V.
If you only see volts on one side, the thermostat is open. You may be able to reset it by pressing its reset button.
If it appears there are volts at the pressure switch output, and the overheat thermostat is closed, then the element is at fault.
We stock controllers, pressure switches, and heaters, so if we can be of any assistance, check our shop, theBottomlessCoffeeShop.
These have been hard to locate at a reasonable price, but we now have the Gaggia TS heating elements in stock.
Rated at 1500W 230V with push fit connections. The element has a thermostat pocket to take the overheat protection thermostat vial.
You can find the element in the coffee machine spare parts section at theBottomlessCoffeeShop.
I get quite a few questions about the Gaggia TS operation, mainly why it does not heat up.
I thought it would be useful to look at the electrical operation of the TS in some detail.
The TS User manual (Google search for Gaggia TS Full Manual TS 03-08-04.pdf) contains a wiring diagram (with a wiring error error in the region of the pump).
The first thing to look at is when the machine is first powered on. No attempt is made here to copy the colours of the actual wiring by the way.
The mains power comes in through the IEC inlet on the underside of the machine (15) and is connected directly to the mains power switch (11). If this is switched on, the neon should light up the switch, and power will be connected to the controller (13) pins 1 and 3.
The controller then monitors the level probes in the water tank (14) and if there is no water in the tank, the controller leaves contact K1 in a position to feed the front panel neon (1) to indicate the tank is empty. The controller will do nothing else until the tank is filled.
When water is detected between the two plates in the water tank (14), contact K1 will changeover after about 1/2 sec. For this reason, if you turn the machine on with the tank full, you will see the neon light for about 1/2 sec.
With K1 switched over, power is provided to one side of K2, and out of controller pin 7 to the coffee switch (10) so a shot can be pulled (see later). Also at this time, the controller looks at the boiler probe (5) and looks for conductivity between this and the element earth wire. If there is no conductivity, it assumes the tank is not full, and so closes K2 to provide power to the pump (12) and to the fill solenoid (9). This allows the pump to pass water through the fill solenoid to the boiler. The solenoid on the group head is not powered, so the pumped water does not reach the coffee.
If the probe is faulty, the boiler might overfill, so the controller only allows the pump to operate for a few minutes at a time. When filling the boiler from empty, it will be necessary to switch the power off and then back on a few times to allow the boiler to completely fill.
When the probe detects the boiler is full, then contact K3 is closed. This allows the heating element to receive power via the pressure switch (4). This is a switch which is closed when the boiler pressure is below 1bar (14 PSI), and opens when it is above 1bar. By opening and closing as the pressure rises and falls, the pressure switch can keep the boiler at the same pressure and hence also temperature.
To prevent the boiler overheating if the pressure switch fails closed, or if contact K3 fails closed even thought there is no water in the boiler, an overheat thermostat is wired into the heating circuit (7).
If the boiler is not heating, the quickest way to diagnose it is to connect a multimeter between points A and B. You should see 230V AC. If not, the controller is most likely at fault. This sadly is the most common cause of failure, but is is quite easy to fix, costing around £65 for a controller which is just swapped with the original one.
If you do see 230V between A and B, then move the probes to between C and B. If you don’t see volts here, then the pressure switch is most likely at fault (about £20 to fix). To confirm this, move the probes to D and C. If you still don’t see volts, then the over-temperature switch is probably tripped or is faulty.
But if you do see volts between C and D, then the element is probably faulty (£60 – £100 to replace).
The final stage is pulling a shot. As discussed above, if there is water in the tank, K1 changes over and provides power to controller pin 7. This feeds the coffee switch (10).
When this switch is closed, it power the pump (green line), and the solenoid on the group head (8). This allows the pump to pump water through the heatexchanger inside the boiler, heating the cold water to around 100degC. The piping then routes it to the solenoid, which now open allows it to run through the coffee.
Finally, there is an 80W cartridge heater (6) which keeps the group head warm via thermostat (2) whenever the mains power switch is on.
We now stock the following items to maintain the TS:
Group head gaskets and screens
Group head heater thermostat (98degC)
Steam and water taps and spare washers
TS Commercial Steam Wand
Pressure Stat (pressure Switch)
Pump (Ulka EP5)
Standard commercial and Bottomless portafilters
Orman kl.1.6 Pressure Gauge
Steam and water tap knobs
On/Off and Coffee Switches
First thing Monday morning is the best time to savour a good cup of coffee in our household, after everyone else has gone out for the day.
Unfortunately, none was to be had. The pump just kept running, but no flow out of the portafilter. Had I left the blind basket in place, it would be easy to do, but no.
Looking in the water tank, it was empty, but why had the machine not cut-out and lit the low water light on the front panel like normal?
Inside the water tank, the water softner cartridge was sitting on its side, so not drawing the last inch of so of water from the tank. No problem, I filled the tank and prepared for it all to work. But no.
The pump had been running for a few minutes by now, so I thought I might have damaged it, although I could occasionally see air bubbles in the return pipe to the tank, so it appeared to be working. They are only supposed to run for a minute, before cooling for 1.5 minutes. The best thing was to let the machine cool and then investigate again.
Some short time later. I turned the machine on, and the pump ran for a few seconds, as it normally does to top up the water tank after the machine has cooled and the water has slightly contracted on cooling as it becomes more dense. So the pump does appear to be working.
But still no coffee flow.
The other likely culprit is the solenoid. This sits on the side of the head and directs the water flow which comes from the tank, through the pump, and through the boiler heat-exchanger to reach the coffee. But it should only do this when you draw a shot. Otherwise, it lets any water above the puck run to the drip tray, so you don’t get splattered with hot water, coffee and steam when you remove the portafilter.
Each time the pump operates when you pull a shot, the coil is energised on the solenoid, and a metal slug inside moves to reroute the water flow. You should hear the coil click and if you hold an insulated screwdriver to the side of the coil you should feel a slight buzz of the magnetic field changing. These two effects are quite distinctive, so if they are not present, the solenoid is probably not working.
To confirm the coil is faulty, check for mains voltage at the coil terminals when pulling a shot. The multimeter is set to AC volts. In the UK the mains supply is nominally 230V AC, so seeing 243V is okay, the solenoid should be switching.
The next thing to do is to check the coil resistance. The multimeter is set to ohms. The display of OL (overload) on this multimeter shows the coil is open-circuit. Not good.
Comparing to a replacement coil, we see a resistance of 0.896k ohms (896 ohms). We are now certain the coil is faulty.
First I removed the drain pipe from the top of the solenoid.
Here you can see it free. The other end connects to a piece of black hose which ends up in the drip tray.
It is not possible to remove the coil from the solenoid without removing the steam tap. Loosen the pipe connection to the tank. Two spanners are required to avoid damage to the pipe. The boiler must of course be cold.
Pull the tap handle off and remove the chrome nut.
Guide the steam tap free.
Here is the replacement coil I hoped to use (right) and the existing coil (left). The existing coil is a Sirai ZA34A. It has the same internal diameter as the Parker ZB09 I planned to replace it with, but as you can see the depth is different.
I did not have a spare Sirai coil in stock, so I replaced the whole solenoid. Note the pipe connection is flat at the top above the screw thread. You need this sort of pipe connection, not the alternative conical one which is more commonly found.
The base dimensions of the valve are pretty much common, so the two valves shown are interchangeable. Although not pictured, you need to remove the top nut of the solenoid and take the coil off to allow access to the four fixing bolts (3mm allen key required).
Orientate the new valve correctly before fixing back into place.
Reconnect the wiring. The closest terminal has a single wire connection from the switch.
No much to say here, other than here it is (right-click, and choose to “save link as”):
Here are some quick videos I made of the operation and internal build of the Bezzera Ellisse.
Internal View (Side 1)
Internal View (Side 2)
This is a write up of a problem I had with the Gaggia TS.
Each morning, I turn on the machine, and allow it to heat up for half an hour or so. The pressure gauge would rise to the normal 1.5bar level, and happily stay there.
I would then draw a shot to make a cappuccino.
Next, I would purge the steam wand – and very little steam would come out. At the same time the pressure gauge would immediately drop to zero and the water in the boiler would start heating. Once it was back up to pressure it would then work completely normally all day.
This puzzled me for a while. My first thought were that it could be the Pressure Stat having dirty contacts. This would mean that it might make initial contact to heat the boiler, but then refuse to make a good connection to maintain the heat. This was dismissed, as the pressure gauge showed pressure, so there must be pressure in the boiler, right ? Wrong.
There WAS pressure in the boiler, it just wasn’t there anymore. My thoughts were that, in the morning I would I switch the machine on and the pressure switch would see no pressure in the boiler and close its contacts to bring on the heater. The pressure would then slowly rise and the gauge needle would register this correctly.
When the boiler was at the correct pressure (1.5bar on my machine) the Pressure Stat contacts would open and turn the element off. For some reason, as the boiler naturally cooled, the pressure reading did not fall and the Pressure Stat did not cut back in to maintain the boiler pressure and hence the temperature.
The fact that the gauge showed 1.5bar, but opening the steam valve caused it to immediately drop, and that the boiler heats normally when the pressure gauge shows less than 1.5bar, and stops at 1.5bar, shows that the gauge, pressure switch and steam wand are operating normally – they just aren’t reliably connected to the boiler.
A scale plug in the boiler outlet would allow pressure to pass from the boiler into the pipework feeding the gauge, pressure switch and steam wand, but would prevent the high flow required to steam the first milk in the morning.
But wait, it works fine for the rest of the day? The scale must be a moveable plug, which once moved by opening the steam valve in the morning then allows the machine to work fine all day. When the machine cools at night, the plug moves to block the system again.
Below is a picture of the connection from the boiler to the steam wand, pressure gauge and pressure switch.
Far fetched? A descale cured the problem. And I have had question from a reader of my blog with the same problem. Hopefully a descale will cure the issue for them.
Update: I have the same problem on another machine. My Bezzera Ellisse is exhibiting exactly the same symptoms, though this machine has separate connections to the boiler for the steam wand, pressure switch and pressure gauge.
It looks like the vacuum breaker has been the problem all along with both these machines.
When the machine is turned off, the pressure in the boiler falls as the water cools. The vacuum breaker is designed to let atmospheric air into the boiler as this happens, meaning that when the boiler is cold, it is at atmospheric pressure. The boiler contains cold water, with a layer of air above it.
Heating the boiler creates steam, which is what we want for our steam wands. As the steam pressure builds, it eventually forces the vacuum breaker closed. You should be able to hear a sudden rush of steam, before the valve abruptly clicks shut. The boiler now contains hot water with a steam blanket above it. The pressure in the boiler then rises until the Pressure Switch opens.
The problem is, if the vacuum breaker sticks shut, when the water cools, air is not admitted via the vacuum breaker. It will enter slowly via the steam taps and perhaps pipework joints. As the water heats, we get hot water with a blanket of hot air above it. Opening the steam valve releases this hot air and the boiler pressure rapidly drops to zero. The hot water is not at boiling point, so the steam is not replenished.
The cure is to descale or replace the vacuum breaker (seen in the centre of the photo below of the internal pipework of the Gaggia TS).
On the Bezzera Ellisse, the vacuum breaker is part of a combined vacuum breaker and pressure release valve assembly. This unscrews (obviously after releasing all pressure), using a 32mm spanner. An adjustable spanner just fits if the rear panels are removed.
Inside the valve is a stainless steel ball bearing which is lifted by the steam pressure to seal the valve. It should be heard to rattle around when the valve is shaken. If not, shock it loose by banging the valve down on a hard surface.
I chose to descale the valve to remove any possible scale causing the valve to stick. Replace using PTFE tape to seal the thread. Do not over-tighten.
Here are my notes about powering up the Bezzera Ellisse for the first time. The previous owner had said it was shooting steam everywhere, so I was prepared for faults. What follows is just how I did it. It is not a recommendation for you to follow. Coffee machines can be very dangerous if not handled with care.
There are two probe connections on the top of the boiler. The left hand one (viewed from the front) is the shortest, and is used to sense when to stop the pump. The right hand one is longer, and when the water level reaches it, it will allow the heating element to turn on (the contactor will pull-in with a clunk).
First, I wanted to check these two circuits worked.
By applying an earth to the shorter probe, the pump would stop.
Lifting the right hand connection would inhibit the heater.
With this arrangement, I switched the power switch to position I. The pump would not operate until the earth was removed, which is correct.
The element contactor would not pull in until an earth was applied to the right hand heater sense wire.
With both of these probe connections appearing to operate correctly, I replaced the connection to their normal positions, and placed the fill hose in a bowl of clean water.
Switching the power switch to position I results in the pump running and the inlet solenoid opening, both taking place after about 5 seconds. Because the pump is not self priming, I used a 100mL syringe to fill the hose, and this was drawn into the pump body. Then the coffee machine filled itself (takes about 10 minutes using this method). I left the steam taps open in case of any overfilling.
When the contactor came in for the heater, I moved the water level sense probe over to the heater level probe. In this way, I could check the pump stopped correctly, because I knew the water level was touching the longer probe. I then restored the connection back to normal. Note: the heating contactor comes in with the switch in position I, but the heater will not power until the switch is in position II.
When the boiler was full, and the fill pump and solenoid switched off, I fixed a thermometer to the side of the boiler and switched the main power switch to position II.
I opened both the steam taps, so no pressure would build up in the boiler and continued heating until the water was boiling.
When steam began to issue from the steam taps, I closed them and confirmed on a test gauge I had fitted to the top of the boiler, that the pressure was building up. This had been fitted in place of the heater pressure switch, and was only being used to briefly confirm that the main pressure gauge was working properly.
Despite the gauge test gauge showing 0.5bar, the main gauge showed zero boiler pressure. So, the first job is to let everything cool down, drain the boiler, and replace this gauge.
With everything cooled, and with the pipework disconnected from the gauge, no water came out. I expected some flow, and after investigation loosening various joints, a blockage in the connection to the boiler was suspected. To attempt to clear it, I filled a syringe with 100mL of neat descaler and connected it to the pressure gauge pipe connection.
With some effort, and carefully holding both the hose junctions in place, I managed to inject some descaler. Then suddenly it all flowed in. Listening near the boiler, I could hear some fizzing, so I left the descaler in place for 10 minutes or so. The boiler will require draining and flushing before use.
By the way, the elbow facing downwards is a drain tap. This has a blanking cap in place to prevent a massive steam outflow if this is inadvertently opened whilst the boiler is full of water over 100degC.
The pressure gauge now agrees with my test gauge (water entry has cause some temporary condensation which should clear over a day or so).
The machine was disconnected and allowed to cool before everything was put back to normal (probe wiring, pressure switch, etc) ready for further testing.
Here is a quick summary of the correct operation of the machine when you switch on:
1. Move the power switch from position 0 to position I. The red neon by the switch lights. If the water level is touching the lowest probe, the contactor is energised (but the heating element is not powered yet). If the water level is not touching the upper probe, the inlet solenoid opens and the water pump operates (takes about 5 seconds to start).
Note, that if the boiler is empty, it may not fill in one go. To prevent flooding if the level sensors fail (due to scale or circuit fault) the fill pump only operates for a limited time. To make sure the boiler is filled, when the pump stops, switch the power switch to position 0 and then back to I, until the pump no longer operates.
The water level sensor operating the filling process has a time delay of approximately 3 seconds, to prevent the pump cycling on and of excessively.
2. Move the power switch from position I to position II. Providing the water level is touching the lowest probe, and therefore the contactor is energised, then the main switch supplies power to the heater via the pressure switch and overheat thermostat. The water heats until a pressure of 1bar is reached and the pressure switch opens. This will be indicated on the front panel gauge.
I am pleased to say we have located a supply of the Orman kl.1.6 gauges, as fitted to the Gaggia TS and TD models, and probably compatable with a few other models as well.
The gauge reads up to 3 bar, but will normally sit at around the 1.5 bar mark.
The connection on the end of the capillary looks a little different to other gauges I have, this one being a female connection on the capillary.
Straightforward replacement whilst maintaining the originallity of the TS.
We now stock the following items to maintain the TS:
Group head gaskets and screens
Group head heater thermostat (98degC)
Steam and water taps and spare washers
TS Commercial Steam Wand
Pump (Ulka EP5)
Standard commercial and Bottomless portafilters
Orman kl.1.6 Pressure Gauge
Steam and water tap knobs
On/Off and Coffee Switches
I bought a Bezerra Ellisse with a fault described as “lots of steam escaping”, so the first task was to take the end cover off the boiler and replace the gasket. This is also a great time to have a look inside.
Disconnect the power. Turn off the water supply.
The boiler can be drained using the tap under the drip tray. Mine was blocked, so I recommend taking a bolt out of the end plate (behind the copper tube in photo below) and siphoning out any remaining water (later edit: it has a blanking plug over the tap outlet – only remove when the boiler is cold).
Make a drawing of the wiring from the pressure switch to the element, and then disconnect the wiring and the pipework at the boiler end and lift the pressure switch clear.
The mains filter may be in the way, so loosen the two allen screws so it can be moved clear if required. The controller backplate also needs to be removed and the controller tied out of the way (not shown).
Remove the earth from the boiler end plate.
Loosen the nuts a little at a time to avoid distorting the plate (17mm socket). You can see here the element has already been removed (together with two of its studs).
With the end plate off, the heat-exchanger pipe can be seen running diagonally. The vertical tube is a baffle around the level probes. There is very little scale in the boiler and the element looks new in the photos below.
The old gasket was brittle and cracked, and is most likely the cause of the steam leak.
Remove all the old gasket material using a scraper and finish with a brass brush.
Place the new gasket in place.
Replace the end plate and tighten the nuts a little at a time, tightening nuts cross-wise to avoid distortion.
Next to be installed is the heater element gasket. This is first slipped on to the element, which is carefully guided into the boiler, before rotating so that the element rests in the lowest part of the boiler.
With the element in place, the wiring connections can be remade.
Re-tighten all the fixing bolts.
Insert the overheat thermostat vial, which slides in about 200mm or so.
Here is the side view of the completed installation.
Once Christmas was out of the way, I had a plan to descale the TS, hopefully to cure an occasional problem with scale blocking the pipes (more of this in a future post). But the machine got the better of me and began dripping from the hot water tap, filling a cup in about an hour. Time to get the taps apart and investigate.
First to come off are the front panel knobs. These should just pull off, but the steam one was stubborn. A bit of levering with a screwdriver….
…and it snapped off. Nothing that the hot glue gun won’t fix later.
With the remnants of the knob removed, the nut bit on the front panel can be removed. Use two good spanners to prevent damage to the pipework.
Continuing with the tap, loosen the copper tubing connection.
Both the steam and water taps can be removed with their spouts still attached.
Using a pair of spanners again (or better still a vice) loosen the pipe connection from the rear of the valve. Undo the final turns of the nut by hand and be ready for it all to fly apart under spring pressure.
In my case the cause of the leak is the perished washer. You can turn these over and reuse the other side, but you will be back here in a year replacing the washer as they become brittle over time.
Hold the body in some grips (protecting it from damage with a cloth) and loosen. If the thread breaks at this stage, a new tap will be required.
This is what it looks like when the old washer has been levered out. Obviously, when putting it back together, just nip it up. It will be so much easier next time.
Scale can build up on the ridge where the washer sits when the valve is closed. Carefully remove it with a blunt tool, or soak in descaler.
This pintle sits between the threaded control knob shaft and the washer carrier. Soak in descaler if required and lubricate with silicone grease before refitting. It should move freely in the brass tap body.
Here is the detail of the Gaggia TS Steam wand, if your machine has the basic panarello milk frother, this is a must do mod. The steam power is almost unbelievable in comparison.
Putting it back together is the reverse of disassembly. Flush through both of the taps to remove any debris, and check for leaks on the pipe connections before replacing the lid. I had to glue the knob back on, which was straightforward with the hot melt glue gun.
We stock the TS wand, spare washers, taps and knobs to buy online if you need them.
When you switch on the power using the main switch on the front panel, power is provided to the front panel neon, which lights provided the thermal fuse in the neutral wire is intact.
Power is also provided to the elements, via the coffee thermostat and the steam thermostat. If either of these has dirty contacts, then they may not provide power to the element, and so it will not heat the water. You may notice the water not heating quickly as the thermostat contacts dirty and create resistance to the current reaching the element. This will only get worse until the thermostats ultimately fail.
When the water in the boiler has reached 95degC, the coffee thermostat will open (4 in the diagram above). The current which was heating the element will now take the alternative route through the neon (11), which has a high resistance, and although in series with the element, will not allow it to continue to heat the water.
Of course if the boiler cools down, the coffee thermostat will close and the cycle will continue. If the coffee thermostat is faulty and the contacts have welded themselves together, then the coffee thermostat will remain closed and heating will continue until the steam thermostat (5) opens and the neon comes on. When a coffee shot is subsequently drawn, steam will come out, rather than hot water.
The coffee switch (9) is closed to pull a shot. This provides power to the pump (10) and the 3-way solenoid (8). The three way solenoid routes the coffee from the boiler to the coffee (it normally sits idle and routes the coffee water to the drain, to release pressure from the puck).
To heat the water to make steam, the steam switch (7) is closed.
This shorts across the 95degC thermostat and so the steam thermostat (5) now controls the boiler temperature.
It also opens the power feed to the solenoid (8), in case the coffee switch has accidentally been left closed, or the coffee switch is operated (otherwise steam would issue from the group head).
When the seam in the boiler is up to temperature (145degC) the steam thermostat (5) opens, and the neon (11) lights again. You can now steam milk.
The Gaggia TS uses a level probe in the water boiler to detect the water level by measuring the conductivity of the water.
The probe is connected to the controller, and there is also a connection to the base of the boiler to form a complete circuit through the boiler and water when the level rises to contact the probe.
If water is not detected by the controller as being in contact with probe, it does not allow the boiler element to switch on.
Over time, scale can build up on the probe, effectively insulating it. In this case, the boiler level may be incorrect (as the water can rise until it is in contact with part of the probe which does not have scale formed on it yet). Over time the level of water will rise in the boiler, and there will be less space for steam.
In the worst case, the water level will not be detected by the controller, and to prevent overfilling, it will stop the fill pump and close the fill solenoid. In this case, the element will not switch on. Note a faulty element, pressurstat, or controller, can also give these symptoms.
To clean the element, remove the orange wire and loosen the smaller lock-nut. The probe can then be withdrawn.
Soak the probe in a small amount of descaler to remove any accumulated calcium carbonate build up.
Re-insert the cleaned probe back through the white insulator and tighten the locknut.
Replace the lid and switch the machine on. Check for steam leaks from the probe area once the boiler is up to pressure. If necessary, switch off and depressurise the boiler (by opening the steam tap) and tighten the probe securing nut.
The following video shows the correct operation of the water level probe.
No coffee today due to a Gaggia TS fault. The red neon on the front panel is permanently lit (usually meaning the water tank is empty). Unfortunately for me it is completely full.
I even tried a pinch of salt in the water to see if it would increase the conductivity and also removing one of the metal strips in the tank and holding it in contact with the other to see if that fooled the controller into thinking there was plenty of water. No luck.
Next thing to check is the wiring. Hoping for a fault here, as a break in the wires from the sensing plates to the controller could save some expense. Sadly these were fine also.
Only thing left was to replace the controller which is low down on the right hand side.
Once unbolted, the connections can be numbered for easy relocation to the replacement controller.
The connections to the tank level probes are on pin 10 (earth to the boiler and to one of the tank probes), and 8 (to the other tank probe). Connection 9 is to the boiler probe.
The new controller is a Giemme RL0 1E/1S/4C/F (also coded as 01.03.0036).
Once in, everything was back to normal.
In case you need to check your own controller, the video below shows how it should work.
I bought a 500g bag of Limini Columbia beans to try, a bag just big enough to get a good appreciation of the flavour of the beans and to ensure that enough beans have been ground to be certain that the grind setting is spot on. Also after about a week to 10 days, the beans have fully degassed and can be appreciated at their best.
The flavour starts with a definite chocolate background with robust follow through. Very rounded with good body. Similar to the Limini Brazilian beans, but with more chocolate and a slightly smoother lasting finish and pleasant aftertaste. No bitterness noticed and very low acidity.
For me, this is one to try side-by-side with the Limini Brazilian beans and is also a strong contender for the status as one of my favourite beans of all time.
You can see the full range at: http://www.liminicoffee.co.uk/productlist.html
I should say, I am not associated in any way with Limini Coffee, I just like their way of doing business, selling excellent coffee beans at un-inflated prices.