a/c water pump

99270fv

i took the boat out for the first cruise of the year. all systems go,, except the new a/c. over the winter I installed a new a/c system, the boat never had one. the a/c will come on and pump cold air until it gets hot and then it shuts down with a E1 error code. the a/c is a webasto with a march pump. I have power to the circuit board and a green com light. it acts as if it will not command the pump to come on.   since I have never owned a boat with a/c should the pump come on when the compressor does or does it command the pump only when it needs it. I have water to the strainer before the pump. could I have plumbed the strainer or pump backwards and misdiagnosed the power supply issue?  

Black_Diamond

The pump must run when the compressor is on. It is shutting down due to an over temp at the compressor.

DanD2

Crack open the line on the other side of the pump after it starts until it spits water.....it may need to be primed.

99270fv

thanks for the replies I will try that maybe today hooked up to the water hose. Is the march pump 110v or 12v? which side of the pump is the inlet the bottom or the side?  

MarkB

The water should start flowing as soon as you turn on the ac. If you don't see water, something is wrong, either seacock is not open or pump is not primed.

99270fv

ok guys I figured it out with your help!! it was not primed. I have learned that the march pump is 110v. I also learned that the a/c will not command the pump to come on until the compressor comes on. so my problem was the compressor would come on send a command for water and would not get any so the over heat protection would shut it all down. the solution today was to hook the flush adapter to the thru hull with the garden hose and hot wire the pump until it circulated thru the a/c w/o the a/c on.

now that I have it primed will it hold this prime while sitting on the trailer and or trailering to the lake?

Black_Diamond

If you close the seacock it will hold its prime. 

99270fv

thanks black diamond.   since I didn't close it then I will have to prime it again?

DanD2

More than likely you will not. The water level outside the boat should be high enough to force the water to the pump. I've had 3 different boats with AC in the last 10 years and have never had to prime once in the water. If you turn it on and water does not feed through, just crack open the line to remove air on the other side of the pump an you'll be all set.

99270fv

well if I do at least I know how now

MarkB

You should not have to reprime. The pump sits below the waterline.

howardrams

99270fv,  Since it sounds like yours needed primed to make it work, its easier to pour some water in through the water outlet port on the side of the boat than from underneath. That's how I get antifreeze in there in winter.  I agree with everyone who said they never need to prime their pumps.  Mine always picks up from the lake even if it had been on trailer.

Ian

The March pump info is quite clear in saying it needs to be installed below the waterline so water always enters the pump without power or priming. Being water cooled this also means there is cooling water there at all times the seacock is open