Heater not working and no water flowing out

[Rohan]

Is this normal?

I'm de-winterizing my sailboat for the first time, after having winterized it for the first time back in November. At that time, the reverse cycle heating system worked just fine. Now when I turn on the heat, it sounds normal, I get no error message on the control panel, the fan is going, but no heat comes out. Also the coils are severely icing over, and no water is flowing through the outtake (both the in and out valves are open and the strainer has been cleaned).

So I look up the problem and one problem may be that the coils ice up because the water temperature is under 40 degrees F. That is possible, because it's still cold outside here. But what worries me more is that water isn't flowing through. The strainer did fill with water so it's coming in, it just isn't going out. So my question is, is that normal for the water to stop flowing when the coils are icing up like that, or am I looking at a separate problem? I would try the AC to see if that works, but it won't even turn on when the temperature is below 65F.

Of course, even with water coming in there is still the possibility that the intake is blocked. I'm not really wild about jumping into freezing cold polluted water to check, so that's why I'm asking here first. But I will if I have to. But if the intake was blocked, then since some water is coming it, I would at least expect to see a trickle of water going out.

[slug]

cooling water flow

Many systems have a thermostatically controlled valve on the sea water supply

[Coolerking]

the pump is airlocked.
or it has failed
bleed it first, then check flow/operation.

[Rohan]

Originally Posted by slug

cooling water flow

Many systems have a thermostatically controlled valve on the sea water supply

I hope that is the case here.

[Rohan]

Originally Posted by Coolerking

the pump is airlocked.
or it has failed
bleed it first, then check flow/operation.

I tried that. I opened up the strainer, did hear a slight hiss of air, but no change. I even tried filling the outflow hose with water, hoping that might help prime the system. Still wouldn't work correctly.

[KadeyKrogen38]

Opening the strainer will not prime the pump. You need to take hose loose from discharge side of pump to bleed air. These pumps do not move air in the line just water.

[guyrj33]

How can you tell the coils are icing up?
Can you hook up city water to the intake and reverse flush the intake?

[Cpt Mark]

STOP!!!!!!!

DO NOT RUN YOUR SYSTEM.

I have the exact same problem even down to the the time of year lol. I have a Marine Aire reverse cycle unit and cannot run it below 40 degrees and I don't try until the water gets to 42.

What happens is when the water goes through the unit it reduces the water temp by 7 degrees F or so. Going through the system you have a bunch of copper tubing etc. What is happening is it is frezing to ice inside. If you run it, you could theoretically freeze the tubing, expand it, rupture and have a non repairable unit.

I went through this with the manufacturer. My water exits a reinforced vinyl hose to my PEX and goes overboard. I can watch the vinyl hose inside turn to ice. It happens so fast it's quite amazing.

I've checked with government source regarding current water temps in the river I live on and have found them to not be accurate. I use a thermometer and check to see when the water is warm enough. I suggest you do the same.

Long story short. Left the boat for 1 week in late November and was injured severely. Came back to the boat 7 weeks later. Had friends watching it for me and all was fine. Had a friend wrap the incoming water in heat tape hoping it would take care of this problem, it doesn't. Walked on board on Monday and noticed what you did, noise, fan, no heat. Immediately checked water output, none. It had been running fine just the day before. How long had it been frozen? No idea. I let it sit for a few days and tried it again briefly and it still works. Yay! I got lucky

[Rohan]

Originally Posted by guyrj33

How can you tell the coils are icing up?
Can you hook up city water to the intake and reverse flush the intake?

By looking at the unit. Within a few minutes you see heavy frost on the outside of the coils. They are black but turn white with a layer of ice.

Due to the layout, it would be very difficult for me to hook up a water hose to the intake, or even just put the intake hose in a bucket of water

[Rohan]

Originally Posted by Cpt Mark

STOP!!!!!!!

DO NOT RUN YOUR SYSTEM.

I have the exact same problem even down to the the time of year lol. I have a Marine Aire reverse cycle unit and cannot run it below 40 degrees and I don't try until the water gets to 42.

Thanks for the advice! I'll wait until it gets warmer. This is my first boat as an owner, and these systems are all new to me. It just blows my mind that the heater won't work when it's really cold outside - just at the time you need it the most! At least I have a space heater...

[Cpt Mark]

You're welcome . I just installed mine a year ago and was really enjoying a warm catamaran throughout. Then it got cold. Cant use it until wx warms up sigh. Lol. I'll be off the river and back onto a as it water in a few months. Lesson learned

[Denallan]

Same happened to me last week .Rear unit ,smaller,worked fine .Front system came on but would not pump water.Seacock open, pump running ,no water out the exit.last year had air in system after launch,had to bleed it out.Thought that was what the problem was,took out hose off ac water coil,still wouldn’t pump through. Took water hose off intake side of ac coil,water pumped through.Water coil on ac was blocked.Went to hardware store to get a piece of hose to blow into the water coil.By the time I got back ,no blockage....ice??? Hooked up all the hoses,water pumped all the way through,system works fine on heat or ac.Maybe once the water is flowing it won’t freeze?

[Cpt Mark]

Originally Posted by Denallan

Same happened to me last week .Rear unit ,smaller,worked fine .Front system came on but would not pump water.Seacock open, pump running ,no water out the exit.last year had air in system after launch,had to bleed it out.Thought that was what the problem was,took out hose off ac water coil,still wouldn’t pump through. Took water hose off intake side of ac coil,water pumped through.Water coil on ac was blocked.Went to hardware store to get a piece of hose to blow into the water coil.By the time I got back ,no blockage....ice??? Hooked up all the hoses,water pumped all the way through,system works fine on heat or ac.Maybe once the water is flowing it won’t freeze?

No. Water running through the system is the culprit. Well, that and physics.

[cal40john]

Originally Posted by Rohan

Thanks for the advice! I'll wait until it gets warmer. This is my first boat as an owner, and these systems are all new to me. It just blows my mind that the heater won't work when it's really cold outside - just at the time you need it the most! At least I have a space heater...

They're really flogging heat pumps for houses in our area because they use less energy. I looked into it for my house. To get the government incentive you are required to have a backup heat source for when it gets too cold for the heat pump to work. Some work down to colder temperatures, but more commonly stop working around 30 degrees F.

[Coolerking]

I must apologise, for some reason i missed the part about the water temp that you are working with...that is your problem, they gradually stop working when the water temp drops.
Some of the newer ones use a hot gas bypass valve to help keep the suction pressure up in cold temps.

Interesting the psi switch didn't cut out.