Xmas in March..Kinda/Grunert Refrigerator

[JamesG161]

I thought I had done a "dumb" thing during the Winter Freeze, which I assumed caused the loss of my Refrigeration Condensing Unit. [18 yrs of service, Grunert]. After much troubleshooting and testing [even have a Capacitance Meter]. I found the compressor pulling too much Amps. So it is boat $pending time again. Good it wasn't our freezing weather preparation.

But...
In plowing through the hatches and stowage to get to all the testing areas I found some previous unknown treasures, left by the Previous Owner. All in mint condition.
1) Uniscope Binoculars 7x50 in hard leather case.
2) Pair of Head Set ,hands free, Walkie Talkies
3) New Volvo Penta 50 hp sea water pump
4) Kohler 9KW parts , belts, air filter, water pump, 4 engine zinc, 2 oil filters, one fuel filter.
5) Penant clips, sail sewing kit, hot knife for cutting nylon ropes, sun glasses neck ties
6) Full set of bedding sheets and pillow cases, but RED, not the Admiral's color.
7) One pair of deck shoes, new, but not our size. Good for guests tho.

And this strange object, which puzzled me at first. Then remembering a video of how to set the tension of you standing rigging from a SBO contributor.

It may not offset my $$$ for a new Condenser unit, but at least something to smile about. Plus the weather was perfect today and sailing fever is rising.

Talk about the Luck of the Scottish errrr I mean near Ireland.
Jim...

PS: The new Grunert is a bit bigger in capacity too.

 

[SFS]

A Loos gauge! Wish I found one lying around on my boat.

 

[Justin_NSA]

That Loos gauge is worth about $100. I have to have 2 to cover all of my wire sizes.
Search the forum on the fridge unit. It may be smarter to upgrade to a new more efficient system. I'm in the same predicament.

 

[jssailem]

Wow @JamesG161 a true Christmas miracle. Only question? Why have you forsaken your Navy training. Usually the Captain of a plane or vessel (especially a sea going vessel) inspects all of the voids before signing for the billion dollar vessel.
You just never know what you are getting into with a new to you vessel. In your case it appears a void of roses.

 

[JamesG161]

inspects all of the voids

Well...
At least on out boat, there are so many "unexpected" void storages spots. Where we had not looked, was the space under the Port side Cockpit Lazarettes. Not inside them, but under them. There was an area about 4" gap that allowed for the Propane line, Refig lines, power lines. etc.
Only 2 points of access. One through the Propane Locker, two tank rack, epoxied down and through Capt cabin, which I had sealed shut with Duct board and metal tape, to prevent sucking Outside air into the AC return. Since my AC guy did the sealing, I never peeked.

Also the Port Side Main Cabin, storage. Evidently the Admiral had inventoried it, but stuffed stuff [ for English majors]. She didn't like the RED bedding from the PO, and on Her side of the bed, plus she hid the "Vox Headset" since it will mess windblown Hair. She has the anchor duty and insists on "hand signals".

I did find, a few years back, 3 fishing rods and 3 water "noodles" stuffed in a almost hidden spot from the PO.

Who knows what more "treasures" are still buried.
Jim...

PS: Have you ever Fished Fish? Or observed that last night it had Snowed Snow?

 

[JamesG161]

I'm in the same predicament.

I did search SBO and Did find a member who "debugged" his Grunert. I sent him a PM too.

After doing a very good troubleshooting job, we found it was the R-22 compressor. Talked Directly with the Dometic [Grunert] technician, who has 25 yrs of Grunert experience. His first response was it is the "Starting Capacitor". But then I explained we have a Capacitance Meter, took it out of circuit, measured 1.75 µF and the range capacitor was 1.2-1.9 microFarads [µF]. Step by step we finally isolated the Compressor going to 40 AC amps for one second before tripping the good 20 amp breaker.

Decision time...
Replace the Tecumseh Compressor, or a New Grunert AC450, with R404 refrigerant and 2 new expansion valves.

The really Cool, thing [pun intended]...
The local Marine Refrigeration shop, owner, has a 50' sailboat in the Long Beach MS marina.

I guess we know why it cost $$ to do marine repairs.

BION, the Admiral wants the New One, her treat.

But I have to admit the Quality from Dometic is top notch.
Jim...

 

[BugOutBoat]

There are basically two capacitors and a relay that control the compressor motor and the sea water pump. If you are seeing a large arc or are tripping the refrigerator breaker it is very likely the Startup Capacitor going out or the start relay is going out. You can order the parts on line and will run you about 35 dollars. The start relay will put the start capacitor in parallel to the compressor motor and the sea water pump, so if both aren't running, it's very likely either the start capacitor or the relay. It's way cheaper than replacing the AC unit. The high current is the Rotor Lock Amps on either the Compressor or the Sea Water pump. The fact that you have it says your compressor and sea water pump are likely ok. If you didn't then they are likely blown. The Start Capacitor suppresses the startup current slightly to allow the AC motors to start. Without the start up capacitor the rotor may lock up and draw a large amount of current and trip breakers. The other capacitor is the run capacitor its used to suppress line current draws while the pump is running. It sits right next to the start capacitor. All of these parts are fairly inexpensive so you could just buy them from vendors directly online. The capacitor may be going out still and may only show signs with enough heating while energized. A capacitance meter may not stress the capacitor in circuit will get stressed by startup currents, which can be up to 60 amps.

 

[BugOutBoat]

When looking down on your Grunert compressor station you will find a clear looking glass type indicator. It will have I believe Red, Yellow and Green. make sure it reads green, that means you have coolant and the only issue is getting the refrigerator compressor and sea water pump working and you should have refrigeration.

 

[BugOutBoat]

you probably don't have to replace the unit. Even if it is 18 years old. Mine is 17 years old.

 

[JamesG161]

A capacitance meter may not stress the capacitor in circuit will get stressed by startup currents, which can be up to 60 amps.

Great tips!
We disconnected the Water Pump, ran Compressor... Trip at 40 amps [2 separate meters confirmed]
We disconnected the Compressor, ran the water pump... good and steady 4 amp. No 20 amp breaker trip.
We disconnected the Capacitor, measured with Capacitance meter. Good mid range of Label on Capacitor.
We can hear the Compressor Start each time, before trip.
We checked each thermostat. Both worked, thus verifying the Dual Holdover plate solenoids and check valves worked.
We checked the High and Low Pressure switches at the power box, but since the compressor never really ran long enough, no luck there.

We will check the sight glass.

We know the Unit worked, after purging the water line [disconnected and drain for freeze protection]. Holdover plates frosted up. It was running well, sea water stream observed normal over board flow.

We left boat for 1 week, came back and 20 amp Refrig, breaker was tripped. No Luck since then. Finally did the trouble shooting, but since I must remove the 2 Propane Tanks and their Epoxied Rack... waiting on Grunert to reply next week. I have to remove the unit, no mater what course we take, but we will check R-22 then.
_____
When I remove the Condenser Unit, the Local Dometic repairman can bench test it. We will do that for sure. That will eliminate the Relay/Capacitor/R-22/Pressure switches for dang sure. I will not remove the power box, yet.

Dual Holdover Plates..

I even asked both Techs...
Any possibility that one of the Check valves were leaking Discharge to Suction?
Ans: Never had that happen... from both.
Jim...

PS: Modifying the Title of this post now.

 

[BugOutBoat]

Mine failed intermittently as well. The typical capacitor failure modes did not occur. Or refrigerator would work one time fine then fail tripping the breaker. The only visible sign on the start capacitor was a very slight residue at the inside of the capacitor top. It was so slight I didn’t think anything of it. Some of the other indications we had is that the compressor ran sickly like it was trying to run but sort of ran poorly. Sometime the sea water pump ran fine and other time it wouldn’t run at all.

 

[BugOutBoat]

Then the 20 amp breaker would trip. I believe this resulted in blowing my AC transfer relay in my Magnasine inverter. What is likely tripping the breaker is the Locked Rotor Amps. The compressor and sea water pump are paralleled in the domestic control panel.

 

[BugOutBoat]

Another way to test your start capacitor is to use a multimeter on the resistance setting. Use a setting like 10 k ohms. Then measure the resistance across the two terminals. You should see the capacitor charge indicated by the resistance reading changing until the reading maxes out. On a digital multimeter this is indicated by the display of the capital letter L. If it never reaches L then replace the Cap. It’s bad. If it takes a long time more than 3 to 5 seconds and still can’t get to L it’s likely bad.

 

[BugOutBoat]

If the cap is good then you should check the start relay. I have a post on my thread on how to check the start relay.