Size of AC seawater pump.

[grandbanksbayfield]

Just installed a new 16000 BTU Webasto AC this last fall. The current pump did a good job on the previous AC, a 16000, but I want to replace it. A new AC will do no good with a dead pump. I cannot see any info on the pump body that tells me the gph or anything - too worn off. Anybody know what I need? It seems like most of them are about 300 or 500.

 

[O C Diver]

Maybe post a picture that someone can identify your pump. Within reason, bigger is always better. For air conditioning, when the ocean gets warm, more flow can be the difference between air conditioning and the unit shutting down. Same for heating when the ocean gets cold.

Ted

 

[Iggy]

If it was me. I would look at the specs of the new AC unit. To see what it calls for. They may want less or more GPH.

In some cases too much flow is no good. I think it depends on the brand. A friend had to much and the unit kept shutting down. It was going into a low pressure warning. The thought was the water was cooling the refrigerant too much. He closed down the sea cock a little and the problem went away.

 

[tiltrider1]

If it was me. I would look at the specs of the new AC unit. To see what it calls for. They may want less or more GPH.

In some cases too much flow is no good. I think it depends on the brand. A friend had to much and the unit kept shutting down. It was going into a low pressure warning. The thought was the water was cooling the refrigerant too much. He closed down the sea cock a little and the problem went away.

+1

Webasto calls for some serious flow. It’s all in the installation manual.

 

[slowgoesit]

At least as important as the size/flow rate of the raw water pump, is to use adequately sized tubing/hose, short hose runs, eliminate 90 deg elbows, etc.

On pump sizing, definitely call the HVAC manufacturer and ask them for a pump recommendation. Even if you don't purchase that exact pump, at least you will have the specs that you need to conform to.