Cruisair reverse cycle...

[Phildorset]

Forgive my ignorance - I'm starting from more of a sailing boat background (+a couple of 20 odd foot Karnic/Boston boats more recently, but have just taken the plunge into motor boats proper.)

Do these heater/air-conditioning units need regular servicing? Or just attending to when they don't appear to be behaving? I'm due to take ownership in 3 weeks of a boat with a Cruisair system fitted, the fans run and it seems to blow hot & cold, but I've no idea if it's performing at it's best or if/when it was last looked at. I guess there's no harm in getting someone to take a look, but maybe they're supposed to be serviced regularly anyway?
The boat will be in Poole and I have found mention of Seacraft in Poole on some older posts on here, but any current advice from you chaps would be very welcome.

 

[pan]

The air filters need cleaning regularly !

 

[superheat6k]

A common fault on any reverse cycle AC unit is the tendency for the reversing valve, a solenoid controlled shuttle valve, to stick in the cooling or heating position after a long time operating in one mode or the other.

Therefore it is worth a periodic change in temperature demand to force a move from one mode to the other. If the reversing valve does stick a sharp rap with a soft face mallet will often free it off.

Otherwise in addition to air filters check the compressor inlet is cold and the outlet hot, with a thorough check for any signs of oil weeps because these indicate refrigerant leaks. If you do suspect a leak then a strong solution of washing up liquid in water with a small paintbrush to apply to all system joints if the most effective way of finding them, but do not use this around electrical components.

If the unit has a water cooled condenser periodically check the strainer is clean and exercise the seacocks.

 

[SpottyDog5]

Evening Trevor, please can you tell me where there shuttle valve is ? My unit has stopped heating,it might need a small word....

 

[Phildorset]

thanks superheat - that's really useful stuff, I'll certainly do the hot cold demand thing and make sure the shuttle valve is switching. Would you say that so long as these checks are not highlighting any issue then it's as well to just let it do it's thing and call in an engineer only when it starts misbehaving? One less annual bill maybe?

 

[superheat6k]

Sealed system fridge systems are one of the few devices that can be left alone and indeed are best off the way, so yes - if it ain't broke don't fix it.

Roy

The reversing valve sits directly on the two pipes from the compressor and changes the gas flow in / out from the condenser / evaporator. They use a small solenoid as a servo, operating a larger shuttle piston in the main valve. Smaller valves may not have a separate servo.

Will look something like this ...



Their off position is normally to cooling so if they are going to stick more likely to be in cooling. Check also the solenoid is energising when in heating mode.

These show quite well how they work ...

 

[SpottyDog5]

Thanks Trevor, just had a quick look the soledoid is operating, but maybe the valve is stuck, will have a proper go in the morning.

 

[Phildorset]

Thanks Trevor - that pic says it all, one less item on the 'annual service' list - will check the bits you previously mentioned, much appreciated. Phil