Replacing pressurestat on Olympia Cremina SL

A haven dedicated to manual espresso machine aficionados.
pcdawson

#1: Post by pcdawson »

Unfortunately the pstat on my new Cremina SL is faulty. The vendor has given me the choice of shipping the new
Pstat to me with instructions for installation, or alternatively taking it to a vendor here in Calgary who they use to service their machines (vendor is in BC). Is this an easy install? I'd be interested in hearing from anyone who has replaced a mater pstat in a Cremina.

Marmot

#2: Post by Marmot »

It is fairly easy. You have to open the case and then on the side you can detach the two cables and unscrew the nuts holding the pstat. You need two wrenches because it is two nuts locked against each other. You can then screw on the new pstat and attach the cables again.

Make sure the vendor sends you a pstat with the right pressure setting. It should idle the machine at about 1.1 to 1.2 bars but you can always adjust pressure by turning the screw on the pstat which will influence temperature.
It is easy to change the pstat but you have to be careful when opening the machine and unscrewing the nuts because you could always scratch the chrome or paint. And when you have installed the pstat you should turn on the machine and let it get up to pressure before putting on the case again to check if the pstat is attached without leaking. Otherwise you have to retighten the nuts or maybe use some teflon tape.

And of course make sure the machine is turned off when opening the case and do not touch any cables when it is turned on ;)

Versalab: maker and supplier of finest espresso equipment
Sponsored by Versalab
pcdawson (original poster)

#3: Post by pcdawson (original poster) »

Thanks so much! Might be good to do this myself so I know how to do it if there is ever a next time. Good point about asking the vendor to send the pstat set to the correct pressure. If they don't , do you know what they are usually set to? I have this image of the boiler pressure madly taking off to 1.8 before I get a chance to make the adjustment.

Marmot

#4: Post by Marmot »

Pressure on the Cremina SL seems to be set to about 1.2 bars. I think pstats should usually be set to a reasonable pressure. If this should not be the case there is always the safety pressure release which will open if pressure gets too high in the boiler.
I think it's a good idea to get to know your machine better. The Cremina SL is pretty simple with little parts but of a very high quality.
You can change pressure in the boiler on the pstat yourself. If you set the pressure higher, you will have hotter water for brewing and more power for steaming milk. If you lower it brewing temperature will drop which could be beneficial for dark roasts.

pcdawson (original poster)

#5: Post by pcdawson (original poster) »

I've got it set right now to cycle from 1.0 to 1.3 after lowering it from 1.2 to 1.4. Of course, with the runaway pstat the cycle occasionally goes well past 1.5.

zan

#6: Post by zan »

In a classic Cremina without spring, before changing the pressurestat if this is a MATER, I would change the microswitch which is very easy to change and should not change the pressure regulation.



The pressurestat has the hydraulic connection with "compression ferrule" very delicate to tighten, 1 3/4 if new or 3/4 "repeated fitting of the union", from SERTO Instalation Instructions.


I hope it will help. Regards

pcdawson (original poster)

#7: Post by pcdawson (original poster) »

Thanks for this. I received the new pressure stat and micro switch yesterday and will likely do the install later this week. One question: the current pstat seems to have settled down somewhat. The deadband seems consistent running from 1.0 to 1.3. However it will occasionally go as high as 1.4 and 1.5. I'm beginning to wonder if this is normal behaviour for this machine. If you're not obsessively watching your pressure gauge over a long period of time, the average user might not spot these occasional fluctuations. No idea what might cause them though.

Weber Workshops: tools for building better coffee
Sponsored by Weber Workshops
zan

#8: Post by zan »

pcdawson wrote: However it will occasionally go as high as 1.4 and 1.5. I'm beginning to wonder if this is normal behaviour for this machine.
I think it may be due to false pressure. Sometimes happens to me.
When the pressure starts to rise, I open the steam wand a little.

After descaling I leave the boiler cup to clean the vacuum breaker in the water of descaling.
Have a good job!

cpreston

#9: Post by cpreston »

In my 2009 Cremina it's definitely not false pressure. I've had two of those Mater pressurestats and both had big dead bands and were erratic. I think that pressurestat is the weakest link in the Cremina.

pcdawson (original poster)

#10: Post by pcdawson (original poster) »

Thanks - those are interesting observations. I was wondering if the deadband and occasional over runs were because the SL is set to a higher pressure. However, it seems as though it's just something that is characteristic of the Mater.