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plumbing hydrohearth to oil burner

HELP! Can someone supply a detailed explanation of how to plumb a hydrohearth (fireplace  boiler) to to oil burner. I want the hydrohearth to preheat the oil burner. We had one of these in the house I grew up in and I remember it greatly reduced oil usage. i found a used one on craigslist which I want to install in a house I just bought. Heat system is single zone. The person I bought it from said to hook it up as its own zone. The circulator pump for the hydrohearth zone should be on continously. An aquastat should be installed in the boiler (or plumb in a well) when boiler comes up to temperature zone circulator kicks on. As heat is sent through radiators boiler temp is reduced and circulator turns off and boiler temperature is increased by the hydrohearth. What prevents oil burner from kicking on when temperature goes down - a 2nd aquastat or relay ? Also how does the house thermostat come into play - is it overridden by the aquastat.

I want to use the hydrohearth as a primary heating source with the oil burner only coming on as needed. I will have a separate gas or electric water heater. In the summer I want to be able to shut off oil burner entirely.

Also I want to eventually convert to gas heat using a mod con boiler. anyone know if I can feed the output from the hydrohearth directly to the input of a mod con boiler. Will the hot water just pass through. Is there such a thing as too hot water in this instance. Would I be better sending the output from the hydrohearth through the radiators  first then to the mod con boiler. Wiil having the hydrohearth void the warranty of a mod con boiler? I know there are examples of solar heated water sent to a mod con boiler. I probably will need to know the output temp of the water from the hydrohearth.

Can a mod con boiler have its intake and vent run pvc through a chimney if there is a fireplace in a an adjacent internally separated chimney. could fireplace fumes enter intake for boiler. Is there a minimum separation distance.

I found the following piping diagram online but it doesn't show the hydrohearth set up as its own zone. I do not have the temp probe shown in the hydrohearth as shown in the diagram below.

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  • Bob Harper
    Bob Harper Member Posts: 1,040

    All bad ideas except getting the mod con. Skip to that and be done with it. Those fireplace boiler devices are illegal since they are unlisted, perform poorly and a few have failed so I recommend against them. Ask yourself this: if they are such a great idea, why isn't everyone else converting to them? As for reusing old equipment like that, I wouldn't recommend it. Radiators are not subjected to uneven heat stresses the way these things are so I don't have a problem reusing them.

    No, you can not run pvc up one flue with the adjacent one being used for heat or fireplace.

    Just put in the mod con and forget using a grossly inefficient unreliable uneven heating appliance such as an open hearth fireplace.
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