Any idea why one air handler on our master stateroom would ice and not the other? Both are on the same compressor and seawater flow is good. I will mention that the last time we tried to use them as a heat pump the valve would not shuttle and it just cooled. The system was working well for weeks afterward, but the past few days I noticed that it was a little humid there.
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Thread: Air handler freezing up
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02-15-2020 12:02 PM #1Senior Member
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Air handler freezing up
Michael & Beth
Hull Number CV312
63’ Cockpit Motor Yacht
1986 model launched in August 1987
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02-15-2020 12:13 PM #2
Re: Air handler freezing up
What's the pressure on the low side (suction)
A single compressor to 2 air handles will not always provide equal pressure and air handles may not be providing the same pressure drop.Scott
41C117 "Hattatude"
Port Canaveral Florida.
Marine Electronics and Electrical Products Distributor.
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02-15-2020 12:19 PM #3
Re: Air handler freezing up
lmost likely low Freon. or restricted air flow across evaporator core .....Pat
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02-16-2020 08:31 AM #4Senior Member
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02-16-2020 10:29 AM #5Senior Member
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Re: Air handler freezing up
Thanks, I’ll see if I can find an a/c guy here in Georgetown Great Exuma to check it out. The filter screen was clean so I suspect low Freon pressure. I’m kicking myself for leaving my gauge set in the storeroom in JAX. If I had brought it along it would have magically ensured that I would have no a/c problems on the trip! Luckily the temps are cool enough to not need it.
Michael & Beth
Hull Number CV312
63’ Cockpit Motor Yacht
1986 model launched in August 1987
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Re: Air handler freezing up
It s definitely either low gas or low air flow.
Try running it at a higher Tstat setting so it cycles on and off, increase the blower setting or maybe run the other unit at a colder setting.Pascal
Miami, FL
1970 53 MY #325 Cummins 6CTAs
2014 26' gaff rigged sloop
2007 Sandbarhopper 13
12' Westphal Cat boat
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02-16-2020 11:09 AM #7Senior Member
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Re: Air handler freezing up
They are dometic/cruisaire units with the digital panel. I can’t run them separately, but I can change the blowers from intermittent to continuous to defrost any freeze up and also not run it so cold. If I can’t find an a/c guy, I’ll tempted to get a can of Freon for car systems and pump a bit in, this would be until I can get it serviced properly. I’ll call my service shop in JAX and find out what gas is in the system first though.
Michael & Beth
Hull Number CV312
63’ Cockpit Motor Yacht
1986 model launched in August 1987
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02-16-2020 01:04 PM #8
Re: Air handler freezing up
You can use the "Delta T" method. It's crude but not completely wrong. Measure the return air, measure the conditioned air. Slowly, little amounts at a time, add refrigerant until you have about a 15º difference. Ideally it should be closer 20º but staying well south of that will keep you from over filling and should get you close enough to stop the freezing. I kept a decades old slightly leaky R22 house system going like this for years.
(Standing by for the beating from the HVAC pros )1978 53' Motor Yacht "LADY KAY V"
Hull number 524
Chesapeake Bay
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02-17-2020 04:00 AM #9
Re: Air handler freezing up
You may find that the Run Capacitor has gone bad causing one of the fans to slow down. (Replaced the run capacitor on same condensor as yours and fans sped up 50% and stateroom cooled quicker.) My 1984 systems use R22. It may say what gas on the condensor label.
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1984 61MY #353 with 9' cockpit extension.
Sydney, Australia.
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Re: Air handler freezing up
I agree with delta T, I use it all the time and I have a complete set of AC equipment in my shop. I check the difference between the air temp into the evap coil and the air out at the closest vent and don't hook up gauges until it drops below 15-18F. The highest evap fan speed may help. Be careful with cans of auto refrigerant as most of them contain stop leak.
GeorgeFlorida
2002 Cabo 47
MAN mechanical 800/8's
"You can avoid reality, but you cannot avoid the consequences of avoiding reality"