GRUNERt - Frig and Freezer

[drtsr1]

I just bought this boat a (2000 Hunter 460). Well the Frig / Freezer work just fine for the week I spent in SC in preparation for delivery, it also worked great for the 3 day trip back to South Florida.

Well this is when the trouble starts, got back to the dock and helped someone with their bag which hurt my back and put me in the hospital (fun stuff).

When I got back to the boat the Frig / Freezer were not working even though the sea water pump continued to run. Needless to say all the food went bad (what a smell).

Note: the thermostat dial in the frig is frozen in the high position and the freezer was left on high when I got taken to the hospital.
I know I will need to replace these dials, do you know of a good place to purchase them.

The big question I have is how do I test the compressor and what should I be looking for?

Does anyone have the spec's on this unit?

 

[kloudie1]

Mr. Kollmann is on this site occasionally.. He is a go-to guy that probably can help. Here is his web site:
http://www.kollmann-marine.com/

 

[Rick486]

Just for information, a friend of mine had one of these Grunert things in his 45 footer and spent a FORTUNE trying to get it to work reliably over about 5 years. Each spring he would have some fridge guy come down and sprinkle magic powder on the thing to get it ready for the season. By Fall his beer was warm. My advice would be to cut your losses, junk it, and buy a new system.

 

[Richard Kollmann]

Grunert has designed and sold 5 to 10 different refrigeration units for pleasure boats in the last 15 years and several more before that. There were two systems that did not last in service their 90 volt DC belt drive and a small 12 volt off brand Spanish made compressor that looks like a Danfoss BD compressor.

Because there are so many different configurations a set of pictures will help. You can email them direct to me. richard@kollmann-marine.com.

 

[Richard Kollmann]

It appears to be a Grunert 110 volt ½ Horse Power Holding plate system in their Passagemaker line.

I need a few more pictures of the complete unit showing solenoid valves and pressure switches. With AC power off remove cover from large refrigerator electrical box and take picture of what is inside.

Is there just one thermostat?

You only said unit did not cool what happens when power is turned on?
Does circuit breaker trip?
If you turn off circuit breaker will water pump stop?
Does the water flow out the through look good?
Does compressor try to run even for one second?

There are safety devices that stop compressor normally these need to be evaluated first.

 

[drtsr1]

It appears to be a Grunert 110 volt ½ Horse Power Holding plate system in their Passagemaker line.

I need a few more pictures of the complete unit showing solenoid valves and pressure switches. With AC power off remove cover from large refrigerator electrical box and take picture of what is inside. WILL SEND IN ANOTHER EMAIL.. NOT VERY GOOD. WILL TAKE MORE TOMORROW

Is there just one thermostat? YES

You only said unit did not cool what happens when power is turned on? WATER PUMP COMES ON ONLY
Does circuit breaker trip? IF YOU MEAN AT PANEL THEN NO
If you turn off circuit breaker will water pump stop? YES
Does the water flow out the through look good? YES
Does compressor try to run even for one second? NO

There are safety devices that stop compressor normally these need to be evaluated first.


Thanks

Rick

 

[Richard Kollmann]

The pictures are a great help. If you look at the bottom right corner of electrical drawing you will see that both the water pump and compressor are powered from the same power terminal source. Your answer that the circuit breaker stops and starts water pump and nothing happens at compressor points to an open circuit at compressor. If there was a mechanical or electrical problem inside compressor generally the circuit breaker would trip.

The problem seems to be with wire connection at compressor or the snap action thermo overload $5 switch at compressor. WARNING I do not know how much experience you have with AC voltages so it must be your decision as to having work done by a qualified person.

In picture showing top of compressor there is a flat spring holding a plastic cover over compressor wire connecters and the round snap action heat and amperage safety switch. After insuring that all electrical power is off remove cover spring and plastic cover. First look for discolored or lose wire connections at compressor. The thermo switch has two wires connected to it. If its cheap contacts become dirty from operating which is common on water cooled units in marine use this switch will fail. If you are in a place where you can get a new switch I would recommend it even if this is not the problem. I have installed a good size jumper wire across this switch for a 10 second run to confirm its condition. ANOTHER WARNING do not operate compressor with switch by passed...Most cities have appliance parts stores that handle the correct switch so take the old one with you.

 

[drtsr1]

Thanks again. I learned a lot now I have to put back together.

The black wire was broken. Replaced and it is running now.

I do have another question?
The looking glass that you can see the fluid run trough, is it suppose to have bubbles in the fluid?

The other question is where can I get the dials that control the temperature in the frig & freezer, also are there anythings I need to know when replacing?

 

[Richard Kollmann]

From the excessive oxidation present where the wire burnt off compressor terminal I would think boat was damp inside for a long time. I would try to free up thermostat with penitent oil like WD40.
Because of low voltage and amperage in that control circuit any standard refrigerator thermostat will work. I am confused I think one picture shows two solenoids one for freezer and the other for refrigerator if this is true there will be two thermostats. Also the control box has diodes to operate compressor if either box requires refrigerant flow. This would also mean that thermostats will have separate temperature ranges freezer and refrigerator models. Two thermostat systems provide great box temperature control when connected to shore power but not as efficient when power is only available an hour or two a day, unless compressor running is controlled manually.

Refrigerant sight glasses used for holding plate systems must be viewed differently and each style of sight glass must be viewed differently. If glass on your system is horizontal facing up with a window larger than ¼ inch, say the size of a quarter. I want to see a river of refrigerant filling ½ that assembly until plate has frost on them. When plate is almost frozen river of pure liquid should rise to above 5/8 level below glass. I would rather have system a little low on refrigerant than too much. Picture #3 shows an oversized receiver that might hold 5 pounds of refrigerant when 2 pounds is more than enough. There are no hermetically sealed compressors that do well when water cooled and especially in boats when overcharged with refrigerant. Amperage on that compressor without the water pump should be slightly less than 7 amps. I am sorry I can not give you a good straight answer to sight glass indication but each holding plate system is different. Do not pay a lot of attention to glass on the first days run. After a dew days running plates should be refrozen in one hour of running time. How long will it be before it is necessary to run compressor again will depend on box’s daily heat load. Many of these plate systems in hot climates require compressor running twice a day.

 

[drtsr1]

Richard, I am trying to wire in a replacement water pump for the unit and I have one more question for you.
I have 3 wires from the pump black, white and green and the wires from the unit are green, brown and light blue.
Question is how do they matchup?

Thanks for any input

 

[Richard Kollmann]

Richard, I am trying to wire in a replacement water pump for the unit and I have one more question for you.
I have 3 wires from the pump black, white and green and the wires from the unit are green, brown and light blue.
Question is how do they matchup?

Thanks for any input

I am not sure either how it is wired. Green would be the earth ground that is left end terminal in grunert box. At the other end of terminal bar are where the other wires that power pump and they are not labled as to collor on this drawing. Match wire colors to right two terminals.