Hot water heater bypass question?

[Zorba]

Take a look at the attached photo. Does the valve circled serve as a bypass?

 

[Sous]

I've got a similar set up and was wondering the same thing. I just got the boat a few months ago and haven't had time to run down all the "little stuff" so I just pulled the lines and did my usual bypass when i winterized last weekend... better safe than sorry!

 

[twomad]

It looks like a shutoff for that manifold. It looks like the hot water heater is being fed off the pump

 

[Zorba]

The hot water heater is fed off of the cold line with the shutoff coming out of the manifold. The pump is fed directly from the tank. The picture cuts that off.

 

[Sous]

Ok, so not to steal Alex's thread, but what is the other line in the bottom of the pic. Looks like a loop going cold in to the hot out side (blue line looped between the two with the arc cut off the bottom of the pic).

 

[Zorba]

Not a steal. I'd like to know myself. All i can come up with its some sort of mixing line to prevent scalding.

 

[Sous]

Not a steal. I'd like to know myself. All i can come up with its some sort of mixing line to prevent scalding.

Ah yea that would make sense... even though my hot water is still pretty freaking hot!

 

[dpmulvey]

Ah yea that would make sense... even though my hot water is still pretty freaking hot!

That's what that black handled valve at the bottom left is for. They often fail. You can get them at an RV place cheaper than a boat place and depending on the heater, at HD or Lowes, cheaper than both.

the newer ones have a return line to mix cold with the hot which if you crank the heater up, theortically doubles the actual capacity.

 

[Sous]

Thanks David, I'll have to check that out next season.

 

[Ray Ray]

Take a look at the attached photo. Does the valve circled serve as a bypass?

Zorba,

You correctly identified that valve as the shut off for the cold water feed into the HWH. Closing it only shuts off the flow from the cold manifold, but doesn't completely by-pass the heater, I believe. I just went through the same thought process while winterizing myself, and determined a full by-pass was needed in order to complete the loop.

You'll note that the cold water feeds in, gets heated, and then exits the HWH in that hot line at the bottom left, which then enters the hot water manifold, feeding hot lines throughout the boat. In order to drain the HWH, and still be able to flush all the lines and push antifreeze, you'll need to fully by-pass the HWH by joining those two lines/points.

I simply added a line, with 1/2 inch male connectors on each end, to the ends of both the cold water line entering the HWH and the hot water line exiting the HWH headed for the hot manifold. That allows the heater to be drained separately, while all fresh water lines (cold and hot) to be purged and flushed as needed.

Hope that helps.

 

[Zorba]

Zorba,

You correctly identified that valve as the shut off for the cold water feed into the HWH. Closing it only shuts off the flow from the cold manifold, but doesn't completely by-pass the heater, I believe. I just went through the same thought process while winterizing myself, and determined a full by-pass was needed in order to complete the loop.

You'll note that the cold water feeds in, gets heated, and then exits the HWH in that hot line at the bottom left, which then enters the hot water manifold, feeding hot lines throughout the boat. In order to drain the HWH, and still be able to flush all the lines and push antifreeze, you'll need to fully by-pass the HWH by joining those two lines/points.

I simply added a line, with 1/2 inch male connectors on each end, to the ends of both the cold water line entering the HWH and the hot water line exiting the HWH headed for the hot manifold. That allows the heater to be drained separately, while all fresh water lines (cold and hot) to be purged and flushed as needed.

Hope that helps.

Thanks Reg,

THats what i was thinking as well. Clearly it's factory since others have it. I just wonder what purpose it serves? Fail-safe if the HWH goes bad, you can still pressurize the system?