Convert Sears Roebuck Millivolt gas to 24 volt valve

Old 02-09-10, 08:55 PM
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Convert Sears Roebuck Millivolt gas to 24 volt valve

I am trying to convert my ancient Sears Roebuck gas furnace that has a millivolt gas valve with a new honeywell vr8300a dual gas valve standing pilot. So I picked it up at Home Depot ... and failed at hooking it up wiring wise.
Currently the system has a taco 3 zone switching relay operating only 2 zones, an aquastat, and millivolt gas valve.
How the heck do I wire this 24v valve to work right ?
The millivolt is dying and needs to be "kicked around" a bit to get the sucker to go ... I need advise quickly if possible
Old 02-09-10, 11:42 PM
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Personally, I wouldn't change it.

If the main burner isn't lighting reliably, the usual reason is a pilot orifice and pilot burner that need to be cleaned.
Old 02-11-10, 08:34 PM
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A millivolt valve uses a pilot generator for electricity (self generating system) A 24 volt valve needs a transformer to reduce line voltage to the needed 24 volts. Also a new pilot to accept a thermocouple. And of course it needs to be wired into a safety circuit as your old valve was, should have been. Seems like a lot of expense for no real reason. Listen to S/P and clean the pilot first. Does your utility co make service calls? If yes, give them a call and ask them to take appropriate voltage reads.
Tell us the make and mod # of the old valve.

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