AC water pump over running

[Wkuhilltopperfan]

When I winterized my boat this winter I accidentally let a air gap into the line, afterwards the AC pump now continues to run weather the heat/AC are running or not. Both Heat and AC both still work normally other than the water pump starts running when the AC breaker is turned on and continues to run until the switch is turned off. I'm guessing a stuck relay, so I took the cover off the relay board and lightly taps each relay hoping to release them if that was the problem ( didn't work) I have also tried to disconnect all power ( 12volt and 110volt ) for a while hoping for a reset (nothing) . Any suggestions would be appreciated and I have a electronics back ground and don't mind installing a external relay if need be.

Thank you

[Viper]

I think you're on the right track. The fault is likely the pump demand circuit in the control box. Does this happen even with power to the AC units shut off or just when they are powered up but not actually running and just on stand-by mode?

[Wkuhilltopperfan]

Source of the post I think you're on the right track. The fault is likely the pump demand circuit in the control box. Does this happen even with power to the AC units shut off or just when they are powered up but not actually running and just on stand-by mode?

If the breaker is on the pump is running, it don't maker if the AC panel is turned of or not

[Viper]

Just to eliminate anything in the AC units, disconnect one at a time in the control box and retry. If the same happens after all are disconnected then it's the control box. If it stops running after disconnecting one of the AC units, the problem is at that unit. If you're electronics savy, It shouldn't be too difficult to source a replacement relay as I suspect that's the issue, and solder it right into the board in place of the faulty one. Look for a schematic in one of the AC manuals or on-line or the inside of the control box cover.

Your winterizing has nothing to do with this.

[Wkuhilltopperfan]

You think much like I do, I'll give that a try

Thank you

[Viper]

My only concern is if the board incorporates an electronic driver circuit trigerring the relay. That may be a little more difficult to isolate. Would have to check the schematic.

[Viper]

Pull the board and see if you can do a continuity check across the relay's NO supply and load terminals. May not be an accurate reading while the unit is part of the circuit though but worth a try before pulling it off. Also, if it's going to be removed anyway, check (I can't remember) if it's possible to remove the relay cover for inspection.

[Wkuhilltopperfan]

I live about an hour away from where I keep my boat slipped, I'll be trying some of your recommendations for sure when I get back down.

Thank you

[SplashyLady]

Depending on which control board you've got - the on-off pump relay on the board may have failed. They do have a tendency to fail closed, so the water pump runs continuously. Do you have a schematic for the control board? The owners manual usually includes one, so you can check the relay and see if it is stuck. You can find a replacement relay and replace the relay on the board if you are good at electronics repair (parts ID, unsoldering, and resoldering). Otherwise a new control board might be the solution.

[Wkuhilltopperfan]

I have all paperwork /manuals/ and parts guide to go with the boat. You guys have had some great suggestions.

Thanks