Author Topic: Large Pleasure Boat Refrigeration System  (Read 92 times)

Richard

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Large Pleasure Boat Refrigeration System
« on: April 26, 2019, 04:56:01 pm »
Just a further bit of information.  When the refrigeration man looked at the system last year he removed the Ranco O10-1416 thermostat and fitted a locally available one with only a single control knob, no proper calibration and no hysteresis adjustment.  Id like to replace it with something like the Ranco but cant find one any more.  What can you recommend?
 
Thanks again for your help and I look forward to your comments.  Ill be back to you with info on the insulation as soon as I can defrost the freezer.
 
ANSWER


Now to your questions and my answers:
 
1.   Yes but the compressor, condenser etc are fitted in a very confined space with little or no ventilation when the boat is in the water.  When we are living aboard on the hard we open up the compartment to let the air in and out and switch off the water pump.  Refrigeration performance is much reduced but we still can freeze the plates.  Should I provide permanent ventilation?
Answer 1.  The more cooling of compressor the longer life for the compressor.
 
2. Unfortunately I have left my contact thermometer at home in Spain so I have had to use an IR gun type thermometer.  The results I have are 31 deg C and 40 deg C.

3. Never to my knowledge. A previous owner may have done so but based on the maintenance done during the 10 years or so prior to my ownership I would say not.
Answer 3.  The water condenser needs water tube cleaned once a year.
 
4.   There was when I first had the boat but one of the so-called technicians said it was a waste of time and removed it.  I still have it so it could be replaced but I have to find someone to do it!
   Answer 4. You dont have to have sight glass to determine correct refrigerant when you can read amperage and see where frost cover is present.

5.   All of the vertical plate (first after the expansion valve) is covered in frost and all of the second plate is covered with a thin film of ice.  Frost builds up quite quickly and can reach 3/4 in about a week.  I cant find a major air leak though.
   Answer 5.  inch frost in a week is caused by air infiltration normally caused lid or door seal leaks. Checking these seals with a ribbon closed in various location around seal should not be easy to pull out with lid or door closed.
 
6.  No accumulator is visible.  (see photos).  The suction line is cold with condensation despite being insulated.
 
7.  8 9 amps approx. based on reading the distribution panel meter.
     
8.  All of the first plate and (I think) all of the second plate is solid.
 
9.  Frost is on both plates and the expansion valve.  The suction line seems wet but not frosted but the insulation on it is not good and is saturated with condensation.  Time for replacement?
     Answer 9. If moisture on refrigerant return line is not a problem for you do not worry about it.

10. R12 and an R12 substitute mix.  The system was topped up with R12 last year having been vented a couple of years back and refilled with the substitute.  If the technician has no more R12 then I am not sure what can be done as he assures me no R12 substitute is now available here in Greece.  I dont have any servicing equipment but would be prepared to buy some if I had some instructions on how to use it.  I now have little faith in local technicians but would need some hand holding to undertake any alterations myself.  Also how I would obtain R12 substitute gas I am not sure but could probably talk to a local a/c man in Spain where I spend my winters.

Answer on refrigerant. Running three hours to freeze plates solid and cool box down the first day is OK, but too long a running time every day there after.
Amperage if it includes the water cooling pump is about one amp low.
All plates would normally have equal frost cover unless the two with less frost are far away from leaking air seal.
I am surprised after 3 hours running time that frost is not present on line leaving refrigerated area.