malc60
Well-Known Member
on my rodman38,the air con works well for about an hour them stops.The fan motor is free running but the actual motor gets very hot, is this normal? give it half an hour then all is well again, Any ideas forum friends?
air con cutting out,why?
- Thread starter malc60
- Start date
malc60
Well-Known Member
p.s. the rodman is in the med and it is very hot at the moment
Robin
Well-Known Member
we hd this in the USA on our liveaboard mobo and it was because the air inlet filter was clogged with dust and the thermostat, mounted in this location to measure incoming air/return air temp was freezing up so quite reasonably didn't switch the unit on, it thought it was cold enough already, our aircon guy gave me a lesson on cleaning filters regularly and charged his usual $85 service call fee.
Rodeo
New Member
Also check the seawater inlet and/or pump. We had a separate controller card (for the sea water pump) that packed up, the Aircon would work for a bit then stop.
Just check that sea water is getting to the aircon unit.
Cheers
Just check that sea water is getting to the aircon unit.
Cheers
superheat6k
Well-Known Member
I would suspect be internal motor thermal protector klixon is tripping the compressor, or a self resetting HP trip is operating.
It is normal for the compressor discharge to get very hot, but not the entire compressor, but depending on what type the top my get hot. If its a tall narrow cylinder with discharge pipe to one side of the top, this is a scroll compressor and the top will get hot, but the lower end should be cooler, with the suction pipe cold. If it is a short dumpy cylinder it should all remain warm, but not hot, apart from the hot discharge pipe and cold suction pipe.
If you have an infrared thermometer check the suction pipe temp, as this should be at least several degrees below the air outlet temp from the cooler matrix (evaporator). If this temp has risen to lukewarm then the unit is likely to be short of gas and this leads to a hot discharge, and hot motor temp, which is where the klixon thermal overload is fitted.
Also check the filters to the evaporator (cooler matrix), condenser clean, or if seawater cooled that the strainer is clean and water is flowing properly, although normally this would cause a high pressure trip.
Assuming it is humid it might be possible to see if it is short of gas by looking at the cooler with the filter cover removed. Follow the pipe back from the compressor suction (cold) pipe, and then follow it back and forth across the grid to see where the sweating starts. This should be within one or two passes of the final outlet to the compressor.
The further back the sweating stops the shorter the gas charge.
Nb this only an idea of checking the charge, ideally you should measure the condenser pipe outlet temp and discharge pressure, for which a special fridge gauge suited to the gas in use is required, especially if you are using R410A. If you can get the discharge pressure, condenser outlet pipe temp and gas type I can tell you if you are likely to be short of gas.
If you are near Majorca I can recommend a good man - Keith Pinder at Balaire.
It is normal for the compressor discharge to get very hot, but not the entire compressor, but depending on what type the top my get hot. If its a tall narrow cylinder with discharge pipe to one side of the top, this is a scroll compressor and the top will get hot, but the lower end should be cooler, with the suction pipe cold. If it is a short dumpy cylinder it should all remain warm, but not hot, apart from the hot discharge pipe and cold suction pipe.
If you have an infrared thermometer check the suction pipe temp, as this should be at least several degrees below the air outlet temp from the cooler matrix (evaporator). If this temp has risen to lukewarm then the unit is likely to be short of gas and this leads to a hot discharge, and hot motor temp, which is where the klixon thermal overload is fitted.
Also check the filters to the evaporator (cooler matrix), condenser clean, or if seawater cooled that the strainer is clean and water is flowing properly, although normally this would cause a high pressure trip.
Assuming it is humid it might be possible to see if it is short of gas by looking at the cooler with the filter cover removed. Follow the pipe back from the compressor suction (cold) pipe, and then follow it back and forth across the grid to see where the sweating starts. This should be within one or two passes of the final outlet to the compressor.
The further back the sweating stops the shorter the gas charge.
Nb this only an idea of checking the charge, ideally you should measure the condenser pipe outlet temp and discharge pressure, for which a special fridge gauge suited to the gas in use is required, especially if you are using R410A. If you can get the discharge pressure, condenser outlet pipe temp and gas type I can tell you if you are likely to be short of gas.
If you are near Majorca I can recommend a good man - Keith Pinder at Balaire.
jimmy_the_builder
Well-Known Member
I had this exact same problem with my air con when it was first installed 18 months ago. It was a defective raw water circulation pump. The installers didn't believe me so they came and sat on the boat for an hour and hey presto! it stopped. It was red hot. They went back to their supplier who confirmed they'd had a batch of faulty pumps. I'm afraid I don't know what make the pump is, it has a dark red body, if that's any help?
Cheers
Jimmy
Hurricane
Well-Known Member
I'm with Jimmy on this one
Poor water flow
All our A/C units failed on HP cutout when we were in Valencia last year.
I opened the sea water strainer and found a plastic disposable glove inside the strainer.
Confident that I had found the problem, I restarted the system
Still a problem - No 1 son insisted that he should look under the boat - "waste of time I said"
He still insisted on diving under and when he emerged he produced a supermarket shopping bag that had been blocking the A/C raw water inlet.
Not had a problem since - in fact I'm sitting inside a nice cool boat in the Med typing this
Poor water flow
All our A/C units failed on HP cutout when we were in Valencia last year.
I opened the sea water strainer and found a plastic disposable glove inside the strainer.
Confident that I had found the problem, I restarted the system
Still a problem - No 1 son insisted that he should look under the boat - "waste of time I said"
He still insisted on diving under and when he emerged he produced a supermarket shopping bag that had been blocking the A/C raw water inlet.
Not had a problem since - in fact I'm sitting inside a nice cool boat in the Med typing this
jrudge
Well-Known Member
The op really needs to say ac make and what is getting hot. Also how old is the kit. I have dometic marineair units. Both 7 years old and I have just replaced both fans with new. One was noisy and the other would sometimes fail to start.
The fan motor did get very hot. I don't know if this is normal as the new ones are a different design (axial). New ones push a lot more air.
The fan motor did get very hot. I don't know if this is normal as the new ones are a different design (axial). New ones push a lot more air.
D
Deleted User YDKXO
Guest
I had a similar problem a few days ago. Check the inlet and outlet flow to/from the seawater pump by removing the inlet/outlet pipes. If the flow to the pump from the seacock seems poor, then you possibly have some debris blocking the seacock inlet (which proved to be my problem). If the flow from the pump to the compressor unit is poor or non-existent, then you probably have a failing seawater pump
Portofino
Well-Known Member
You may be able sight the sea water outlet as well to check flow.
Aside from the tech / gas pressure/ leak.?theory Clean all the air filters ,vents etc
Aside from the tech / gas pressure/ leak.?theory Clean all the air filters ,vents etc
Robin
Well-Known Member
In our marina the water is so silty and full of marin growth that people add bromide tablets to the inlet filters to prevent mollusk build up, plus most big boats have monthly diver cleans to check anodes and clear any through hull fittings of crud. We had to have ours backflushed a couple of times and in the end they ran a descaler fluid (muriatic acid?) through on a continuous loop to/from a 5 gallon tub for an hour or so, that was very effective. You could walk the docks and see that flow from some boats aircon outlets was down to a mere trickle because everybody has their aircon running 24/7 even if they are not on board, just to control humidity and mould growth. Now we are no longer living aboard and now have a smller sailboat with just two aircon units WE switch ours off when we are not on board, that also saves us $40/month in leccy fees.