Air Con

jcwads

jcwads

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Hello

First time I’ve encountered a problem with the air conditioning on my T40.

Its a Cruisair unit. The control panel was set to cool. Then it changed and started counting down from 90 or something of that sorts. As it counted down the air was warm coming out. Then at the end of the countdown it went to cool again?

Any suggestions on a fix / solution highly appreciated. This is new unknown territory for me.

Thank you.
 
How long had it been on before it went into this mode ?

Probably simply puts the system into heat pump mode to defrost the evaporator (indoor) coil.

DavidJ idea is good, but a low gas charge can also cause ice build up, what is your ambient temperature ? Ice should never build up above say 18oC outdoor temperature on a direct expansion system.
 
5 mins I’d say. We had it running all last night in port and was ok. Then switched on at anchor this afternoon and the issue occurred. Based in med so it’s circa 25 degrees
 
jcwads said:
5 mins I’d say. We had it running all last night in port and was ok. Then switched on at anchor this afternoon and the issue occurred. Based in med so it’s circa 25 degrees
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I would suggest you have the gas charge checked. Your evaporator coil should never form ice if you are blowing air at 25oC over it.
 
IIRC My system does that normally when staring, it allows time for the sea water pump to start to move water through the condenser, before starting the refrigeration cycle to avoid it going out on high pressure when cooling.....
 
Mind you 90s does sound excessive, I wonder if you can adjust the timer, my manuals are on the boat so cannot check.

As SH6 has said: The evaporator or indoor section can freeze if low on gas, but the unit should go out on LP and it would certainly defrost over night, in heating mode, its the condenser/outdoor section that can freeze and then the unit may reverse cycle to defrost for a few moments. If its cooling and not tripping, I would leave it alone.
 
This might be a quick temporary fix.
Next to the compressor, you should find a solenoid valve that switches the A/C system from cooling to heating.
These valves sometime stick or oscillate.
By default, the system is in cooling mode so simply remove the wire (spade terminals) from the solenoid valve and you might get your system working again as a cooling system only.

Hope that helps.
 
If it’s been extraordinary humid despite what SH6 says for U.K. AC ( there’s shower or cooking steam swirling about in the saloon ?? ) then as JRudge says they sometimes need a quick defrost .Or it’s detected a high H and thinks it needs a quick heat dry before cooling off the fins .

If it works albeit after its 90 sor so delay cooling leave well alone .
The Fr in Antibes will up sell you a whole new unit beware .

As said ^^^ check the dust filters and check the drain on the pan .Make sure the fin pack is clean , shift all the dust with a hover .
I wouldn’t disconnect anything as per Hurricanes suggestion how ever helpful intended .

Just pull the shore power while investigating and cleaning as damp/ water / condensation and AC , as in the 220 V can be lethal .

How’s it been the next day (s) ? Btw
 
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jcwads said:
5 mins I’d say. We had it running all last night in port and was ok. Then switched on at anchor this afternoon and the issue occurred. Based in med so it’s circa 25 degrees
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That’s the clue ……@ anchor !

Question the power of the geny to feed it esp at its compressor start up .
Thats what the 90 s delay is telling you it’s having to manage the geny supply .
 
Been through this countless times possible more than EGT s :).

Conventional AC compressors at start spike up and the supply be it the shore trips or something else in the boat trips or the geny struggles .It’s not just the amps with the geny it’s also the Fq , hertz thingy related to the revolutions of the thing .

Frigomar a brushless D.C. motor powered compressor air con system .

Without boring the t*ts of everyone I run 42 000 btu Aircon from a tiny 3.5 Kv geny ……+ some headroom for other stuff even the cook top .The current draw never spikes being DC the motor speeds of the comp are variable .So no hissy fits , cut outs , shore power going click when every one returns and plugs in .
Talking tiny 3 A to give relatively massive 42 K BTU of cooling something like that with conventional would be teens amps and more at the spike risking a trip .

Sure there are nowadays with AC motors with supposed slow ramp ups but even so they are high by comparison to brushless D.C. motors .

Todays sermon over :)
 
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Portofino said:
….. then as JRudge says they sometimes need a quick defrost .Or it’s detected a high H and thinks it needs a quick heat dry before cooling off the fins ….
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A reverse cycle heat pump only goes into defrost when in the heating, not cooling mode.

Defrost may be timed or temperature terminated when in heating mode, sensing the outdoor coil section which freezes, not the indoor coil.

If in cooling mode, as suggested, when operating it would naturally remove moisture (dehum) from the air.

If the cooling coil is freezing, it’s likely what SH6 suggests, low on gas, or low airflow across the evaporator coil as others have suggested.

This would drop the evaporator pressure (LP) some may be interested to know what SH6 name means. The coil then starts to freeze, causing less airflow, freezes more, until it drops out on LP. Which may have an auto-reset time sequence. It may then work OK next time, until the LP drops again.

Get it serviced by an AC engineer..!
 
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