Grunert Refrigeration leaking seawater

Tony B

.
Oct 21, 2019
4
Freedom F 40/40 Richmond, CA
Hi folks I have a Grunert motor driven refrigeration system and the condenser unit is leaking seawater. It does this at both places where the copper tubing goes into the white casing of the condenser units. My assumption it that both of the nuts where the copper tubing goes in are just compression fittings to hold the sea water in and have nothing to do with the coolant (Freon). I assume that I can loosen these, apply some plumbers tape and screw them back on. But never having worked on a refrigeration unit I don’t want to make any stupid (expensive) mistakes. Can any one confirm my assumptions? Any “gotchas” I should be aware of?
Thanks,
Tony
 
Jan 11, 2014
11,323
Sabre 362 113 Fair Haven, NY
If the fittings are compression fittings tape won't solve the problem. I'd be more concerned about corrosion. If the refrigeration is still working, i.e., keeping things cold, then the refrigerant is not leaking yet.
 
Feb 14, 2014
7,400
Hunter 430 Waveland, MS
My Grunert model has no copper fittings on the seawater. All copper nuts are on the "Freon" side.

Do you have your Grunert model number?
There are factory Grunert Technician available to talk with.

The schematic, model number and phone number are on the inside of the power panel cover.
Jim...
 

Tony B

.
Oct 21, 2019
4
Freedom F 40/40 Richmond, CA
It is similar to this model. Grunert Caribbean Engine Drive/Belt Driven Models | Ocean Options, Inc.

I talking about where the copper tubes enter the casing of the condenser (the white canister). This is where sea water surrounds the copper condenser coils and cools the refrigerant. I think these nuts just hold the sea water in and keep them it leaking out where the copper tubes go in. It appears to be leaking on the threaded side. Not in the compression side.

Thanks,
Tony
 
Jan 11, 2014
11,323
Sabre 362 113 Fair Haven, NY
The condenser is basically a heat exchanger. The refrigerant is pumped through a small copper tube and compressed back into a liquid. Seawater surrounds the tube and removes the heat generated from compressing the refrigerant gas back into a liquid. From the manual, it looks like the seawater is injected by fairly large ¾" ? hoses that are secured with clamps.

Seawater leaking around the compression fittings suggests to me, that the housing is failing not the joint. A picture of your installation would be really helpful.

I have a Grunnert, but the other model, the Mariner Belt Driven model.
 
Feb 14, 2014
7,400
Hunter 430 Waveland, MS
Seawater leaking around the compression fittings suggests to me, that the housing is failing not the joint
:plus::plus:
Not a compression fitting tho.
_______
I guessed that was your model. Thanks for the link.

My guess at what is happening....
1) The condenser housing material and the Fittings are not compatible.
2) Perhaps someone replace the elbows with copper?
3) Seawater [salty] will corrode copper.

If my Guess is right, what I would do
1) Get a PVC or Bronze elbows and match them for barbed hose fittings and screwed threads.
2) Before replacing, I would clean my exchanger by soaking in a solution that removes fouling on the Refrigerant tubbing exterior.
3) Make sure and double clamp the sea water hoses [shown in diagram too]. If one comes loose, you can fill your boat with sea water quickly.

Your sea water pump is low pressure, so if the condenser tank threads are still good, you shouldn't need more than teflon tape to make a good seal.

Jim...
 

Tony B

.
Oct 21, 2019
4
Freedom F 40/40 Richmond, CA
Sorry guys. Maybe I am not explaining it well. I get what the condenser is and how it works. It is NOT leaking from where sea water enters and exits. But from where the refrigerant tubes enter and exit. If you follow the link I posted, and look at the photo, you will see the cylindrical condenser on the right. There are two fittings sticking up in the air. Where those fittings tread onto the housing is where it is leaking. They certainly appear to be original equipment. They appear to be compression fittings around the tubing where it enters the housing. Screwing onto to the housing to keep the sea water from leaking out around the refrigerant tubes. From the threaded side. I am just trying to make sure that if I unscrew them I am not going to cause a refrigerant leak.
 
Feb 14, 2014
7,400
Hunter 430 Waveland, MS
I am just trying to make sure that if I unscrew them I am not going to cause a refrigerant leak.
GrunertPassage.jpeg


I did this from that manual you linked.
The skinny lines are refrigerant lines.

I would take a close up picture of the culprit connections to the "Cooling Tank" leaking seawater and call Dometic in Pompano FL.

You will get an operator and ask to talk to a Grunert Technical Service. I have done this.
I got a fellow named Barry [memory recall] who had 28 years as a Grunert technician.
Tell the Tech what you see and he may ask for the picture by email.

Otherwise, my guess is you may leak refrigerant, which is guess what.... R-22. [not easy to get for recharging]
_______
That condenser tank, per manual, comes in different sizes and sold as a unit.

Good Luck and keep this thread posted with your findings.
Jim...
 
  • Like
Likes: Tony B

Tony B

.
Oct 21, 2019
4
Freedom F 40/40 Richmond, CA
Thanks Jim I will try calling them. Reached out to a couple of reseller’s support centers but got no response.