Grunert Passagemaker Refrigeration Problem

[Bowedtoothdoc]

Hello all,
My Passage 450 has the original Grunert 110v cold plate system using a single compressor and water pump for both a fridge and freezer. Several years back I replaced the two manual thermostat controls with digital/chinese controls and everything has been working properly until just recently. What has now happened is that the freezer is still cooling properly, but the fridge is not cooling. When the fridge kicks on the compressor and water pump both run, but the plate does not cool? I know that these units are old, but hopefully this is a small repair? Any help or input is greatly appreciated?

 

[JamesG161]

You should have 2 refrigeration expansion valves near your cold plates and 2 solenoid return valves.

One solenoid is connected to the freezer and one to the refrigerator cold plate.

Sound like the refrig thermostat is bad or the return solenoid is stuck CLOSED [ not open as was my original post].
Jim...

 

[JamesG161]

Here a faded graphic to help, I hope.

S1 solenoid is controlled by the thermostat in refrigerator.

Test...
1) Turn both thermostats OFF.
2) Wait about 10 minutes.
3) Turn refrigerator thermostat to coldest spot.

If that starts your compressor then the thermostat is good. If the single refrigerator cold plate does NOT get cold, then it is probably your solenoid.
Jim...

 

[Bowedtoothdoc]

Jim,
Thanks for the information and I apologize for not getting back here sooner.
It looks like from your diagram that the solenoid needing to be replaced is in the same compartment with the compressor and the control unit. Does anyone know if this can be replaced without having to recharge the system? I am trying to figure out if this is something I can do on my own or if I need to call a refrigeration technician?

 

[JamesG161]

Does anyone know if this can be replaced without having to recharge the system?

It is most likely the 12VDC activator and not the valve body itself. So no refrigerant lost.

I talked with a Grunert technician about even the check valves. If you call Dometic and ask for Grunert service tech with your model number he can probably get you the part number.
I found my model info on the inside of the Power box cover and their phone number in Pompano FL.

Did you try my suggested test [post#3] which should pinpoint the thermostat or solenoid?
Jim...

PS: Full replacement for mine was estimated at $5000. I replaced my unit compressor, which is the main working part, for ≈$1000 complete. Works great again.

 

[Bowedtoothdoc]

Update as I have additional info....Unfortunately yesterday I was able to remove the Solenoid body and confirm with a metal screwdriver that the magnetic field activates with the 12v dc current. So it appears that my problem may lie in the valve body itself?
In answer to your above question, yes I was able to eliminate the thermostat as the issue. So I have contacted a local technician to have a look as the system may have to be depressurized?

 

[JamesG161]

my problem may lie in the valve body itself?

Ok, good trouble shooting.
But you can confirm the valve is working manually too.

Lets make sure we have our terms right or you can call me by phone.
1) Solenoid is the 12 VDC actuator you tested
2) Valve is the "valve body"

The solenoid get power from the Power BOX
The Power Box circuits gets information from the thermostat.

So with the Solenoid off the Valve but still connected to the Power box you should see the solenoid activate when the compressor starts up.

I seriously doubt you need to call a refrigeration tech yet.
Jim...

 

[Steve760]

JamesG161 You mentioned that you found a replacement compressor for your unit. Where did you find it? im having the same issue and i've already had the expansion valves and the solenoids replaced but its still having the same issue (intermittently) that Bowedtothedoc was having. I'm just having a hell of a time finding parts online for these units.

 

[JamesG161]

JamesG161 You mentioned that you found a replacement compressor for your unit.

yes I did but it took R-22 , which is hard to find and costly.
So i am going to call Dometic again to find the newest version using R-402a and new expansion valve to match.
The rest of my unit is in great shape.

I will let you know my findings when i get it.
My last years replacement from Tecumseh cost me $600 [wholesale from my AC guy] plus install of $300 + $100 R-22 from an leak after install. Not sure why it leaked after about a year. I had hoped it would last longer than me.

I was warned about R-22 but wanted it fixed fast.
Jim...