Replace one air conditioner in dual air conditioner setup with one water pump

[jlombardo]

I have a 1998 Mainship 31 Sedan Bridge. My forward air conditioner needs replacement. The boat is fitted with two units working off one raw water pump. Does anyone know where the relay is located on this boat and if it is terribly difficult to wire into a new unit.

The unit that I am replacing is a Marine Air 9K. I am replacing it with a Marine Air 11K, both are 115v. I don't believe that the current Marine Air is the same company from 20 years ago. I believe that the original Marine Air went out of business in 2006.

I assume that it should be a simple two/three wire hookup for power and probably another two wires for the water pump relay but have no experience with multi air conditioners working off a single pump.

Any advice would be greatly appreciated. (no hire a professional please) I try to do as much work on my boat as possible.

Thank you,
John

 

[rslifkin]

On shared pump setups that I'm familiar with, the relay connections hook up to the pump output terminals on each A/C control board. So to replace an A/C you just swap the power and pump connections over like you would for a normal install, the only difference is that the pump connections go to the relay box instead of directly to the pump.

 

[jlombardo]

Thanks for the input. I will get my manuals out and try to identify which connections are the pump connections.

 

[DennisB1]

Thanks for the input. I will get my manuals out and try to identify which connections are the pump connections.

I replaced a Marine Air unit and the wire connections are easy> As I remember the first three connectors wire green (ground body) white 120 v ground, Black 120 Hot. There were two additional connections for control of the water pump all on the same terminal board. On my boat a single water pump supports three AC units. The relays were bypassed and a single circuit breaker turns the pump on for all three and stays on until the circuit breaker is opened.
Dennis

 

[ranger58sb]

I have a 1998 Mainship 31 Sedan Bridge. My forward air conditioner needs replacement. The boat is fitted with two units working off one raw water pump.

The unit that I am replacing is a Marine Air 9K. I am replacing it with a Marine Air 11K, both are 115v. I don't believe that the current Marine Air is the same company from 20 years ago. I believe that the original Marine Air went out of business in 2006.

I assume that it should be a simple two/three wire hookup for power and probably another two wires for the water pump relay but have no experience with multi air conditioners working off a single pump.

It's quite common to service multiple ACs with a single water pump.

There was a Marine Airrrrrrr company that likely made your original ACs, and which might have been named Vector Compact models. Morphed to Vector Turbo models, and then Marine Airrrrrr was acquired by Dometic (as was Cruisair, and their Stowaway self-contained units). Vector Turbo models have since morphed to being named DTGs.

The other company called Marine Air -- or maybe it's Marine Aire -- is different. Seem to have a decent reputation.

FWIW, we've replaced Vector Compact and Stowaway units with Vector Turbo and DTG models; good improvements.

-Chris

 

[Turtle Blues]

With 2 units it is possible that the pump wires were "daisy chained" from one unit to the other and then to the pump. Under that setup either unit energized the pump. Preferred and necessary when stepping up to 3 units is a pump control box. If one exists it is about the size of the unit control box and has a bank of relays inside. Follow the pump wires to confirm what exists.
Not to be critical but description above just wasn't a proper repair.

 

[jlombardo]

With 2 units it is possible that the pump wires were "daisy chained" from one unit to the other and then to the pump. Under that setup either unit energized the pump. Preferred and necessary when stepping up to 3 units is a pump control box. If one exists it is about the size of the unit control box and has a bank of relays inside. Follow the pump wires to confirm what exists.
Not to be critical but description above just wasn't a proper repair.

Based on both responses, it sounds like, as long as I take the pump wires from the existing units pump connections and connect them to the new units pump connection, I should be okay.

 

[Turtle Blues]

If that what is existing yes it should work.