Boiler operating temperature

Old 03-19-12, 10:21 PM
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Boiler operating temperature

I'm using the NG boiler to support an IWH and radiant heat (primary/secondary via a mixing valve). Suppose I want to run the IWH at 160F. Where should the boiler be set for max efficiency?
Old 03-20-12, 03:00 PM
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I don't know about 'efficiency'... that's not really what you are asking I don't think.

May I ask why you want to run an indirect at 160 ?

I would think that the boiler water needs to be at LEAST 20 hotter than the desired WH temp.
Old 03-21-12, 06:16 PM
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All indirect outputs are rated at 180 - 200f boiler water input. If you lower the boiler water temp your recovery will be slower. If you raise the tank temperature you will use more fuel and chance someone will get scolded due to increased DHW temp. I would not raise the temp that high unless there is need for it. If you raise the temp and add a mixing valve you will extend the draw time on the tank.

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