Water heater to boiler configuration

Can you please explain why this gas-powered tank water heater is connected to a boiler system even though the water heater is independently heated by a burn chamber at the bottom?

The water heater is not labeled as an indirect water heater.

It appears that the cold water supply line for the water heater connects to the boiler system’s hydronic heating system near the hydronic-heater expansion tank.

Doesn’t the closest flame on the supply line in the burn chamber look like it’s leaking, causing the yellow flame?

I do not have your answer, but the flue connection is suspect to me as well. Just thought I would toss that in. :smile:

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Is the flue connection from the water heater exhaust flue to the wye right above it the part that looks suspect?

The supply line to the burner is leaking causing the yellow flame (the yellow flame is due to the leak not being the correct orifice size). Good call but probably not an issue.

The flue appears to be OK: the smaller (BTU) unit, (water heater) enters ABOVE the larger unit. As for the crazy plumbing arrangement I couldn’t say.

Yes, Oversized wye, bigger flue connecting to small etc. I would have to do some research.

It’s not connected to the boiler. You must understand the system if you feel compelled to report on configurations. This is a beautiful install with excellent workmanship!

I agree, that flame is outside the burner.


I think I see it. Blue is cold in, red is hot out.

You’re pretty close Brian but not quite there

What is make up water, exactly? The cold water supply line to the water heater appears to be tapped into by some line coming off of the boiler near that expansion tank. I don’t get it.

You need to understand the configuration. There is a cold water supply to the boiler before the valve for the water heater. This will fill the boiler system. The next component is a pressure reducing valve bringing the pressure down to 12 psi. The rest is boiler 101.

These are two separate systems with the cold water supply from the water heater supplying the make up water for the boiler.

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You can also see how the cold water supply line is coming out of the wall right behind the water heater.

Now I’m starting to understand, @mwilles. At first I thought that the water was moving from the boiler to the water heater, but it makes sense that it’s moving from the cold water supply line to the boiler. Thank you, good buddy.

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What about the drip leg? :partying_face:


Keep up the good questions and ask the right questions you’re getting it.:slightly_smiling_face:

I do now :+1: :+1:

Tony……that’s all I got my friend.

Drip legs were missing from the gas lines of both appliances. Furthermore, the local municipal inspectors could care less about drip legs on gas lines, which is why the contractors rarely install them. I call out the missing drip legs either way, though.

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Umm…Sediment trap dangit!!! :rofl: :rofl: :rofl:

Dirt legs dang it! Where’s the Drip Leg Kid!!!