need dual heat source thermostat


Old 09-21-12, 07:34 PM
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Lightbulb need dual heat source thermostat

hi i'm trying to find a thermostat to run my two heat sources. i have a boiler with 24v controls and a pellet stove with 12v controls. i would like to have my pellet stove be primary heat and if it can't make demand the boiler would run. i have looked for t-stats that fit this idea. my goal is one t-stat, with two heat stages, that are stagered.
please advise.
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Old 09-21-12, 09:06 PM
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Only way we can get around this if you add another relay to keep the 12v away from the 24v that that t-stat needs to run on.
Old 09-21-12, 09:07 PM
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You will have trouble finding a two stage thermostat that will switch two different control voltages without adding relays.

What works well for me with electric forced air heat in series with a wood burning furnace is two identical Honeywell TH5220D thermostats that are set a degree or two apart.

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