Lelit PL41PLUST (AUS) with PID - aka Glenda - Pump only functions when machine cold

Equipment doesn't work? Troubleshooting? If you're handy, members can help.
mshannon

#1: Post by mshannon »

Hi Gurus

I'm a Lelit combi owner and recently came across another Lelit machine (PL41PLUSTAUS) on FB marketplace with PID and 58MM grouphead that seemed like a potential upgrade over my current PL042QE not to mention the original PL042 I had before that.

The PL41 PLUS T owner had purchased the machine interstate from CoffeeCo here in Aus back in 2012 - and had done very little to no servicing since short of backwashing.

He mentioned the machine worked, but if left on for too long after pouring a shot, would fail to pump.

I popped the lid up top and had a look around, and noticed the screw holding the PID temp probe to the boiler was essentially completely rusted out, but other than that, the machine looked pretty immaculate inside. Everything seemed to work with my little test, with exception of the coffee ready indicator light and I decided to take a gamble and purchase the machine (second hand) - assuming maybe a thermostat or PID issue.

Taking the machine home I popped the lid again, switched the indicator lights around and confirmed the indicator light just appears to be blown - and I can now see it come on/off. I miraculously was able to remove the rusted screw connecting the PID probe to the boiler without stripping it and replaced it. I also took the grouphead / screen / gasket etc apart and cleaned up 10 years of build up and it all looks pretty immaculate. Thinking job well done, I put everything back together with plans to buy a simple replacement indicator lamp from a local electrical store.

Turning the machine back on though, and switching the pump on, the pump wouldn't start up. If I put my ear to the machine, I could hear a slight difference between the pump on/off - but not the usual loud pump noise. Remembering what the seller had mentioned, I decided to put the machine outside in the cold and give it time to cool down.

An hour later, plugged it in once more, and sure enough the pump sprang to life - with water exiting the grouphead or steam wand depending on the coffee / hot water setting I chose. Reading these forums, I came across a post from Alan Frew Lelit Anita stopped working (who funnily enough runs Coffee for Connoisseurs and was where my original PL042 was obtained from), that mentioned to check the resettable button on the thermostat and push it in. I had tried that (prior to putting machine outside to cool down) and it made no difference.

Any ideas what could be the problem? Unlike my combi, everything in the Glenda is rather condensed and tricky to get at - particularly the pump.

cheers

Matt.

JRising
Team HB

#2: Post by JRising »

I would say "Dead pump".
Possibly the safety thermal protection on the side of the pump if temperature really makes that much difference, but I hardly ever see those fail unless you pull 'em out by their wires and break them. I see dead Ulka pumps daily.

If you take the thermal protection out of the circuit, just run the wire to the pump instead of through the thermal protection, does the pump still misbehave?
(Don't run the pump more than 60 seconds without the thermal protection in series with the pump, and all that... Don't drive drunk without a seatbelt, either, or something like that...)

mshannon (original poster)

#3: Post by mshannon (original poster) »

Thanks so much for the reply.

Is the thermal protection part of the pump assembly itself, or separate? Unlike other Lelit models - I cannot see any dedicated thermostat associated with the pump like that seen below - so not exactly sure what to bypass -
(pump thermostat https://www.1st-line.com/buy/lelit-9600056/ is for the Lelit Anita (PL042EM, PL042EMD, PL042TEMD), Anna (PL41LEM), Elizabeth (PL92T), Grace (PL81T), Kate (PL82T), Mara (PL62, PL62S, PL62T), & Victoria (PL91T) espresso machine models.)


This is the part diagram for the machine I have -
https://www.1st-line.com/technical-supp ... st-glenda/


The pump worked fine this morning with machine turned on for 30 minutes - and I was able to pull a shot...


... however I switched to the steaming mode to froth milk, and watched the PID rise up to 150c then the PID flashed "A2".

Similar to what was simulated in this video
Someone described similar issue here:
https://coffeesnobs.com.au/forum/equipm ... ays-a2-huh

The three thermostats from I can tell on the machine are:

115c https://www.1st-line.com/buy/lelit-ther ... it-glenda/
125c https://www.1st-line.com/buy/lelit-mc031/
165c https://www.1st-line.com/buy/lelit-mc032/

Is the 125c thermostat supposed to stop power to the boiler when in steaming mode once the temp hits 125d Celsius? Is it possible this is malfunctioning?
Can an ohm reading work out if the thermostat is bad?

Any idea if the PID on this Lelit controls both brew and steam, or just brew?

Does it work simply by turning heating element on/off, or can it control the amount of power supplied to heating element?

Sorry for all the stupid Qs!

cheers

Matt.

patcof1

#4: Post by patcof1 »

mshannon wrote: Any idea if the PID on this Lelit controls both brew and steam, or just brew?
Does it work simply by turning heating element on/off, or can it control the amount of power supplied to heating element?
Matt.
If I understand correctly the Lelit PL41PLUST functions as following :
The 115 deg thermostat turns On/Off the "Ready to use steam" light.
The steam thermostat turns On/Off the boiler heating element during steaming function.
The 165 deg thermostat is the resettable safety thermostat that prevents boiler overheating.
I think that the PID on this Lelit PL41PLUST controls only the brew temperature. For controlling the brew temperature the PID turns the heating element On/Off in very short interval pulses by driving the SSR.

I hope you can let us know in detail what was the cause of the symptom you found on your PL41PLUST.

mshannon (original poster)

#5: Post by mshannon (original poster) »

Posted a video below - that shows the boiler temperature when steam mode activated climbing to 150 degrees Celsius -

www.youtube.com

/watch?v=QK8YROw60ro

mshannon (original poster)

#6: Post by mshannon (original poster) »

Checked the thermostats with a multimeter set to Ohms - and they all went to around 0.1 with multimemter set to 200 ohms

The boiler in my particular machine PL41PLUSTAUS - appears to be more *similar* to the boiller linked at
https://www.1st-line.com/wp-content/upl ... scaled.jpg

rather than the boiler shown at
https://www.1st-line.com/technical-supp ... st-glenda/

.. though my boiler unlike that seen at ...
https://www.1st-line.com/wp-content/upl ... scaled.jpg
has just the three thermostats.

The side mounted bottom thermostat is the MC032 - Resettable 165 degree Celsius thermostat
The side mounted top thermostat is the MC031-115 - 115 degree Celsius thermostat
The top mounted thermostat is the MC031-140 - 140 degree Celsius thermostat


I wonder if the 140c thermostat is supposed to stop the boiler from exceeding that temperature in the steam function? Mine appears to go much hotter - and possibly when the PID exceeds a max temp flashes the A2 restricting power to the pump?

mshannon (original poster)

#7: Post by mshannon (original poster) »

www.youtube.com

/watch?v=OvP1qBlJaGA

patcof1

#8: Post by patcof1 »

mshannon wrote:Posted a video below - that shows the boiler temperature when steam mode activated climbing to 150 degrees Celsius -
I think your video shows normal functioning of a PL41PLUST. When you switch the steam switch ON, the steam lamp lights. And at the moment the temp reaches 115 deg, the steam lamp does not light anymore, that is normal, it just indicates that you can begin your steaming work. The flashing temp digits simply indicate that the temperature at that time is too hot for brewing coffee, that is normal.
And at the moment the temp reaches 140 deg, the steam thermostat must swithch off the heater element. As you probably know, typical bimetal thermostats can have overshoot of approximately 10 degrees. That is why the flashing temp digits can show higher than 140 deg at some time. Google bimetal thermostat temperature control.
I hope you can let us know in detail what was the cause of the pumping fault symptom you found on your PL41PLUST.

JRising
Team HB

#9: Post by JRising »

mshannon wrote: Is the thermal protection part of the pump assembly itself, or separate?
Matt.
Right there, in the pocket on the coil of the pump.


2 white wires going into the blue semiconductor.

patcof1

#10: Post by patcof1 »

mshannon wrote:possibly when the PID exceeds a max temp flashes the A2 restricting power to the pump?
The PID in the PL41PLUST can never control the pump. The PID only controls the heating element in the boiler in brew mode.