Profitec Pro 700 - Steam bubbling in water tank

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

#1: Post by neutro »

I have a new problem with my 2014 Profitec Pro 700, and I'm seeking advice on how to diagnose and repair this peculiar issue.

Full context: my pump was seized and I just changed it. Turning the machine on for the first time with the new pump, the pump did not automatically activate to fill the boilers, but I could make it work using the group lever. After a bit of air got out, water came out of the group. I decided to wait for the machine to heat up completely before declaring victory though, just in case a leak would become apparent once operating temperature was reached.

I noticed the steam boiler raised its temperature somewhat slower than it used to, without the telltale sound of the vacuum breaker bubbling. Instead, I heard gurgling in the water tank. It looks like steam was escaping there -- not a huge quantity, but probably enough to prevent pressure from rising in the steam boiler. Putting my hand in the tank close to bubbles, they were indeed very hot, and both the intake line and the pump were extremely hot. Notably, at this point, the pump would not be able to provide water at the group.

My take on this is that the pump was probably filled with steam. The only way I see this happening is if the 2-way solenoid valve is not doing its job and is letting steam from the steam boiler down the fill line.

Now I don't think I've made any water line nor electrical wire connection errors, but I need to double-check this, as at one point in my previous investigation of the pump issue, I removed the power switch. I wonder if a wrong connection could mess with the operation of the valve and filling of the boilers, but I don't see how.

So here are some questions that I have on that topic:
  • Am I right to focus on the 2-way Solenoid valve?
  • Could the valve issue have been present before and wrecked my pump (e.g. causing cavitation as it sent steam down the line)?
  • Should I just replace the valve and ask questions later or is there something else to do? I see I could perhaps attempt to clean it? Or would it be a waste of time?
  • Could this be caused by any other defective part in the machine?
As always, thanks for any hint.

Team HB

#2: Post by JRising »

You have to look into this.
If that water is flowing back over your brand new pump, it will ruin the pump. The pump can't handle boiling water.

Look back at the plumbing from the pump outlet. The first Tee fitting has the capillary to the gauge. The second Tee splits the brew circuit from the steam circuit. Brew circuit's first component is the brew circuit's check valve. Steam Circuit has the boiler fill solenoid, then the steam circuit's check valve. The one that is painfully hot when this leakage back to reservoir is happening is the one that's leaking internally. You can try just descaling that circuit, but if it still leaks after descaling, you'll have to remove, open, examine and decide if you can fix it or replace it.

And yes. If it is the steam circuit (not the brew circuit), then you'll also want to be cleaning the solenoid valve.

neutro (original poster)

#3: Post by neutro (original poster) »

I shut down the machine before the steam boiler reached 100 deg C so I hope I prevented any damage to the pump.

The plumbing seems fine (I'll post a picture later when I'm back home) as I have not touched anything after the pump outlet's braided hose.

But thanks for providing a way to make sure which of the steam or brew circuit is the culprit. You made me realize it could also be the brew circuit.

The fact that the bubbling starts when the steam boiler gets hot and not before seems to point one direction more than the other though. Also, the water level in the tank was not rising, and the water did not get significantly hotter, so I guess only steam made its way back there.

I must also point out that when this machine is in normal operation, I use it plumbed-in, so if there was a "back-leak" to the pump, I probably wouldn't have had any indication. That being said, everything was working fine until the old pump seized. Now that I got it out, I am totally unable to make it turn using a screwdriver.

Again, this help is much appreciated.


#4: Post by kitt »

Definitely worth checking the 'no-return' or check valves, i had the steam boiler one fail on a new machine recently and it produced the same symptoms . Remove the no return valve and check to see if you can blow through it both ways, should be one way only. I simply dismantled it and cleaned out some debris and it was all fixed. Part number 29 on my exploded view, just above the boiler fill solenoid

neutro (original poster)

#5: Post by neutro (original poster) replying to kitt »

I'll definitely check out the no-return valves; I have the diagram, I see what you are talking about.

neutro (original poster)

#6: Post by neutro (original poster) »

The plot thickens -- I've run a quick test with the steam boiler shut off (so brew boiler only). Hot water definitely flows down to the pump -- after a while the whole brew circuit down to the pump becomes very hot. Furthermore, I noticed that the pump pressure ramps up quite high even with no portafilter on the group, so there might be a flow restriction somewhere.

I have an idea regarding what might have happened. After kitchen reno work, I failed to properly flush the new water line for the machine. I flushed it -- but apparently not long enough, as the inlet filter got clogged by what looks like sawdust. Some of the dust might have found its way to the anti-return valves (and possibly the 2-way solenoid as well) and jammed them.

So the safest path seems to take both lines out and clean them along with the valves and see if I can fix this. I might also take down the brew boiler just in case to clean it as well -- I just hope that the group itself is not clogged.

I'll report back in this thread but this might take a while... Wish me luck!

Team HB

#7: Post by JRising »

I wish you luck and I suggest doing the brew circuit's check valve first since you have proven it to be internally leaking.
Part # C229900548, if it comes down to replacing the check-valve.

neutro (original poster)

#8: Post by neutro (original poster) replying to JRising »

Do you think this part would be compatible? It's listed as ECM #C229900540... Close enough?

I'll see if there is any way to clean those first, and I hope I did not damage the new pump. Exposure to hot water is perhaps a few minutes at most, but having to buy a new pump as well as new valves would start to get expensive very quickly.

So guys, always flush your new water lines profusely before connecting your plumbed-in machine.

Team HB

#9: Post by JRising »

I see the 548 number in the parts lists for Technika, Mechanika, Synchronika, Pro 700 etc...
I think the 540 number on that site is a typo on that site. It is the correct valve for sure.

neutro (original poster)

#10: Post by neutro (original poster) »

So I'm currently in the process of dismantling the brew boiler and all the plumbing between the pump and the two boilers. I know have access to the no return valves. I'm about to descale everything but before I put it all together, I'd need a way to ensure all parts work well, in particular the valves. I followed the instructions here for the 2-way solenoid valve (everything seems fine to me), but the only hint I got for the check valves are from @kitt:
kitt wrote:Remove the no return valve and check to see if you can blow through it both ways, should be one way only.
I've got access to the steam circuit check valve now and honestly, I just can't blow through it at all, one way or the other. What is the "activation pressure" of a check valve? Is it at all possible to check without pressurizing the system? Should I really be able to blow through it in one direction?

Thanks again for any advice.