Water heater connections for Yanmar 2GM20F

[denhams]

I am connecting a water heater with an internal heat exchanger to my Yanmar 2GM20F. I've located the two plugs on the engine for the supply to the heater.

However, I don't know which is the output (from the engine) and which is the return. Also, what are the thread sizes of the plugs?

Regards,

Stephen.

 

[vyv_cox]

On my 3GM30F the calorifier coil is connected in series with the heat exchanger by adding appropriate lengths of hose. Put the calorifier between the pump and the exchanger.

 

[steve_cronin]

My last boat had this engine with water heating but asadly I let the full Yanmar Workshop manual go with the engine. However I have stayed in contact with the new owner and I'm sure that he will photocopy the relevant pages for you.
Please send a private message to me with contact detaila and I'll put you both in touch.

Steve Cronin

 

[paulrossall]

I have a 2GM20 and even though I do have the Service Manual (which covers your model) I cannot find the answer to your question. I would phone E.P.Barrus, who are the UK importer and distributor, and ask for their technical department. I have found them very helpfull and you will probably find they can tell you the answers without having to refer to any manual. Phone 01869 363636.

 

[vyv_cox]

I looked at mine last night. The fittings look like 1/2 inch BSP, usually the common size sold in chandlers. One each side of the water pump. The one coming out of the hot side goes to the top of the calorifier coil,