Gruenert fridge problem out in the boonies

[Calypso52]

Cruising the St. John River, virtually no marine services here.
Symptoms:
System has a separate box for fridge and freezer.
If I run freezer box with the thermostat in the fridge off, it chills normally, down to zero if I want. No clicking sound
If I run both, neither chills. Clicking sound
If I run fridge alone, it does not chill. Well the plates get just a little cold, but basically that box could be a freezer too if I let the system run. Clicking sound.
Clicking sound coming from the T fitting which I assume is the low pressure return for both fridge and freezer. Has larger tubing going into it, much larger than the high pressure tubing coming out of the two solenoids.
I spoke by phone to my fridge tech, he thought it might be a sticky solenoid and suggested a little percussive maintenance. No joy. Clicking is not coming from the solenoid anyway. I tried tapping on the T fitting too.
Is there some kind of one way valve in that T fitting that is not allowing coolant to flow on the fridge side?
System worked at the beginning of this trip and has worked flawlessly for years, other than consuming beaucoup amps.
Any other suggestions I can try myself? Have no refrigeration tools on board.
Thanks!

[botanybay]

Originally Posted by Calypso52

Cruising the St. John River, virtually no marine services here.
Symptoms:
System has a separate box for fridge and freezer.
If I run freezer box with the thermostat in the fridge off, it chills normally, down to zero if I want. No clicking sound
If I run both, neither chills. Clicking sound
If I run fridge alone, it does not chill. Well the plates get just a little cold, but basically that box could be a freezer too if I let the system run. Clicking sound.
Clicking sound coming from the T fitting which I assume is the low pressure return for both fridge and freezer. Has larger tubing going into it, much larger than the high pressure tubing coming out of the two solenoids.
I spoke by phone to my fridge tech, he thought it might be a sticky solenoid and suggested a little percussive maintenance. No joy. Clicking is not coming from the solenoid anyway. I tried tapping on the T fitting too.
Is there some kind of one way valve in that T fitting that is not allowing coolant to flow on the fridge side?
System worked at the beginning of this trip and has worked flawlessly for years, other than consuming beaucoup amps.
Any other suggestions I can try myself? Have no refrigeration tools on board.
Thanks!

I am definitely not an expert. My system is similar, just before the t are two cylinders. These are check valves and you may find one of them chattering.

Might be an indication of liquid refrigerant getting past the check valve and flashing. I can see oscillating suction pressure on the low side.

I did have one plate fail with refrigerant leaking into the holding plate and possibly moisture into the gas circuit but perhaps not the later.

Some indication of a bad expansion valve. Stuck or plugged with debris.

[Calypso52]

Thanks all for your suggestions.

Turned out it was low on refrigerant. Took 20 oz. out of an estimated total of 32 oz. Hasn't been re-charged since 2008, so I guess we'll keep it for a few more years.

[botanybay]

Originally Posted by Calypso52

Thanks all for your suggestions.

Turned out it was low on refrigerant. Took 20 oz. out of an estimated total of 32 oz. Hasn't been re-charged since 2008, so I guess we'll keep it for a few more years.

Did you evacuate and recharge or just add refrigerant?

Any idea why low refrigerant would cause that kind of noise?

Thanks for the feedback.

[Calypso52]

The clicking on the check valve may have been an independent symptom. I'll let you know if it returns.
Detected a small leak at one of the expansion valves. My tech tightened it as much as he dared given the age of the fitting. I'll monitor it for leakage, but if it took six years to leak enough to become a problem, it must be a small leak.
Did not evacuate, just added.

[hellosailor]

If it lost 20 oz. on six years, it isn't a small leak. Not a gross leak, but not really small, since there are sniffers and microphone detectors that can and will detect leaks that are way smaller than that. Of course the art of using them, like poker, golf, and sail trimming, is a somewhat difficult art to master.

If the tech thinks the leak was coming from a threaded joint that was o-ring sealed? There are sealants sold by Loctite for just that purpose. They wick in and seal, and lock, the joint. With varying success but they sell the stuff to seal pinhole leaks in nuclear plants too. So, you might ask them about the best product and try adding it to any suspect threaded joints you have.

[bstreep]

Sorry, but in my opinion, 6 years between charges isn't THAT big a deal, except that it's likely a newish problem.

In the event your solenoids are old, be aware that there's no need to replace them with Dometic's parts. They wanted almost $300 for ours, and I bought replacements (valve plus coil) for a grand total of $34. Exactly the same parts, just missing the Grunert paint.

These are fairly complex systems to work on. If your tech is not a refrigeration tech, it may be above them. That being said, I've done a LOT of work on our Grunert Passagemaker.

BTW, sniffers didn't work on ours AT ALL. Seems the insulation foam poured into our boxes set them off. Crazy. Big Blu spray works GREAT for finding leaks. Wish I'd found that stuff years ago.

P.S. No need to evacuate and refill if you didn't lose it all.

[Calypso52]

Update on Calypso. Fridge/freezer is working like a champ again! Now I need to establish a new baseline on my amp hours/day with a full charge. Thanks for the suggestions.