Can I bypass heater?

[tuanp]

I have an '85 SeaRay with a 170MR model engine (alpha I gen one Mercruiser). This boat is equipped with a heater that consists of a small radiator with a blower fan behind it. There's a tee on the hose that runs from the thermostat housing to the heat exchanger (port side); a smaller hose runs from the tee to one end of the heater radiator, and another hose runs from the other end back to another hose on the starboard side of the engine, again joined with a tee.<br /><br />Now there's a leak in the radiator, I believe, as water/coolant is dripping from the it. I don't need to use the heater, so instead of replacing the radiator, I want to just remove the heater from the system. I plan to disconnect the tee's from the hoses on the engine and replace them with copper couplers.<br /><br />My question is whether this is ok to do. I think with the heater attached, the coolant is just being routed in a loop, and I'm just taking that loop out. Basically, I just want to work-around the leak and get the engine running. Please advise if this sounds ok. Thanks in advance.<br /><br />tuan

 

[snapperbait]

Re: Can I bypass heater?

Yep.. it's a loop.. Disconnect it like you stated and you'll be fine..

 

[yoced]

Re: Can I bypass heater?

like snapper said, you have it exactly right.

 

[tuanp]

Re: Can I bypass heater?

Thanks for the replies. I'll go ahead as planned.<br /><br />There's something about the original setup that I wonder about though. The water that's diverted to the radiator, which is hot, goes out of the radiator and back to the hose that goes into the water pump, which is supposed to feed cooled water into the engine block (as I understand it). I assume that when the blower fan is on, the hot water will be cooled as it travels through the radiator. But what about when the heater fan isn't on, is it still being cooled? If not, then isn't all that water going back into the water pump and engine block still hot?

 

[18rabbit]

Re: Can I bypass heater?

My setup has a solenoid valve that shuts off all water flow into the heater when “off”. This keeps all hot water out of the heater when not in use, and thus nothing hot flows back into the engine. I might be wrong but I don’t think the heater’s radiator is making much of an impact on the temp of the water flowing thru it.<br /><br />Your problem has caused me to think about our setup. When offshore we cannot sustain a catastrophic failure in the heater’s heat exchange radiator. We have a closed cooling system for the engine (keel cooler) and any loss of coolant would be serious…sensors in the coolant reservoir would shut the engine down. I’m thinking of a ball valve installed before and after the heat exchanger system to allow quick isolation of it if ever needed.

 

[tuanp]

Re: Can I bypass heater?

Sounds like I'd be better off without the heater, if it's not cooling that water any and the still-hot water is going back into the block. My setup doesn't have any valve; the on/off switch simply turns the blower fan on/off.<br /><br />It seems like a bad design if all this is true; and it's so obvious I don't think SeaRay would implement it like that. I wonder if I'm missing something.

 

[John Carpenter]

Re: Can I bypass heater?

I'm wondering too...is this a heater with duct work that is blowing warm air into the cabin of the boat....or is it a closed cooling system for the boats engine?

 

[tuanp]

Re: Can I bypass heater?

The boat has closed cooling. I think the heater is for passenger warming, although it's mounted under one of the transom seats and blows air into the open, not into the cabin; so I don't think it's very effective for heating.