I think I have a pressure problem. My Expobar Pulser is about 5 years old. It has started hissing and had steam coming from the front two knobs - so I disassembled it and attempted to tighten the fittings - but they were plenty tight. I powered it up again and found that steam is also escaping from what looks like a relief valve on the boiler.

The unit has never been modified or adjusted by - all factory.

This may have been changing over the last 3 months since I know I used to have trouble with it pushing through a tightly packed, fine ground coffee and now it blasts through anything and is burning some shots.

My questions are:
*) Has something worn out if I have experienced this over time or do the heating / cooling cycles just throw off the PSTAT over time?
*) If it is the PSTAT adjustment (or can be reconciled using by it), I am not really setup to make calculated adjustments and would tend to just adjust it down until it stops steaming and maybe a little lower. Any advice for this method?

Thanks for any help,
D.

Hi Darren

It sounds like your pressure stat does not work at all and your element just keep on warming up the water - this sounds dangerous to me especially because your machine does not have a pressure gauge installed and you cant monitor the pressure.

If your pressure stat is still working and has just gone out there is no way for you to know how high to set it. One uses the pressure gauge to adjust the pstat to.

Rather take your machine in to your local supplier to test.

If it was my machine I would find a way to install a pressure gauge. Even if it is hidden inside the machine.

Kind Regards
Renier

Djsdjs wrote:I powered it up again and found that steam is also escaping from what looks like a relief valve on the boiler.

From your description, it's not clear what the problem is... sticky pressurestat maybe? That's my guess since the pressure relief valve is opening. Over time, pressurestats fail due to the diaphragm hardening, carbon building up on the contacts, or the contacts welding themselves together. Depending on how much use the machine saw, five years is a good run for the pressurestat in the Expobar; I recommend replacing it (search the forums, there are many threads discussing this procedure).

Djsdjs wrote:This may have been changing over the last 3 months since I know I used to have trouble with it pushing through a tightly packed, fine ground coffee and now it blasts through anything and is burning some shots.

This is a separate problem. It may be that the pump is failing too, but I would worry about the pressurestat first. Vibratory pumps also fail over time due to the small valve balls deforming (see repairing a ULKA vibe pump for photos of the internals).

Thanks for the pointers. Was a stuck pstat. Followed the second to last reply on this thread: http://www.home-barista.com/espresso-ma ... -t536.html for unsticking a Ceme pstat. We'll see how long it lasts.

It must have been adjusted incorrectly from the factory because it never used to push through anything more than two exact tablespoons of lightly tamped, not too fine, not too moist grounds - and the grounds were not dry after making espresso. Now it has no problem with 3 tablespoons of fairly moist, fine ground coffee and the grounds have to be tapped out (they aren't bone dry - but stick like I would expect).

Sure wish they hadn't left the stainless protection plastic coating on the back of the water reservoir area during manufacturing - it bubbled and touched a hot water pipe.

Must be machine fixing month for me - had to dig to the center of my HP laserjet 2200 printer to grease a micromotor and it's back and running! Seemed funny that even with it being full of electronics all it needed some old fashioned lubrication.

D.

Djsdjs wrote:It must have been adjusted incorrectly from the factory because it never used to push through anything more than two exact tablespoons of lightly tamped, not too fine, not too moist grounds - and the grounds were not dry after making espresso. Now it has no problem with 3 tablespoons of fairly moist, fine ground coffee and the grounds have to be tapped out (they aren't bone dry - but stick like I would expect).

I don't understand your point, but just to be clear, steam boiler pressure (pressurestat) and brew pressure (pump) are not related. I recommend reading some of the threads linked from this forum's FAQs and Favorites under Vibratory pumps. Since the Expobar Pulser doesn't have an onboard brew pressure gauge, the first step is confirming the actual brew pressure using a portafilter with gauge.