Blockage in condenser coil

[Mike Oatsvall]

Turned on the heater this weekend and discovered that water was not coming out of the thru hull fitting. Checked the obvious, valve was open, cleaned the grass out of the strainer and put it back on and the pump seemed to be pumping. I removed the out flow side of the condensor coil and made sure it was clear to the outside fitting. Finally figured out that water was going into the coil but not out. This took about a hour to do all this. Probably could have done it faster without my wife standing over me shivering and asking "is it fixed yet?" Ran the unit in AC mode for a couple of minutes and reversed it back to heat and it started flowing. It's not been cold enough to get ice in the coil and it had not run long enough to "freeze up". I have no clue what was in there other than something organic that finally softened up and was spit out.
Finally , my question is this: can one snake the coil? I was reluctant to run a wire or something in the coil not knowing if there are valves or perhaps damaging the freon jacket.
Any suggestion on how to unclog the condenser coil?
Thanks,
Mike Oatsvall
Four Winds
H33

 

[kloudie1]

Mike, you probably did have ice in the "condenser" which is the cold evaporator when in heat mode. With low or no water flow from the previous blockage the heat exchanger probably froze pretty hard .. When you put it back in AC mode, the heat exchanger got hot because it was back to being a hot side condenser, which melted the ice plug. With good water flow reestablished, the exchanger should be fine.

 

[kloudie1]

Ohhh I didn't answer your other question.. It is possible to snake out the heat exchanger coil but you'd want to be very careful to not puncture the inner tube. The seawater side typically has corrigations (wrinkles) in it to aid heat transfer. Those could catch the cleaning rod. I would think something like an old piece of coated life line wire with some tape on the tip could be used to rod the exchanger out, but like I noted, you've most likely fixed the problem when you cleared the strainer and established good water flow. The heater works by pumping the cold out of the boat air and into the water. If the water isn't flowing from a clog or a plugged strainer or bad pump or whatever, the water in the heat exchanger will quickly freeze..

 

[John T1594]

The owners manual for the AC unit on my boat recommends cleaning and flushing the coil with an acid solution to get rid of organic material. Sort of like acid washing the hull. I'm sure you can find the manual online for your unit and get the procedure and acid strength formula.

 

[Alan]

Use Tracs Barnacle Buster to flush out any water cooling system. It removes all marine growth as well as calcium, rust, lime and most other mineral deposits. It aint cheap but it works and is biodegradable.