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tennisSB · Nov 13, 2007, 12:53 PM

Hi,

I recently moved in to a condo with a Fraser Johnson Model V1000 HVAC system. It's probably over 20 years old. The cold air works great but the heat doesn't.

The pilot is lit, the fan works, vents are clean, but the burner is not kicking on so only cold air is coming out.

Also when I set the thermostat to turn on auto it never kicks on the fan I have to manually set the fan to on.

I went through the instructions to turn the burner on but though the pilot is on when I move the dial to furnace control dial from "PILOT" to "ON" it doesn't kick on the burners.

Any ideas/suggestions? Thanks.

KISS · Nov 13, 2007, 01:21 PM

Fan operation is a separate entity.

When there is a call for heat, the fan and burner usually come on. The limit switch usually provides some delay for the fan to initially turn on with a call for heat and it also provides some delay so that the fan runs for a while after the burners shut down. This can also be done with timers.

Your burner control usually has three positions: OFF (the pilot goes out), Piltot (Only the pilot stays lit and the position is used to re-light the pilot). ON - The gas valve is controlled by the thermostat.

You do have the furnace in the "HEAT" mode with the setpoint higher than the temperature at the stat?

eschuen · Nov 13, 2007, 04:30 PM

Since your a/s is working we can rule out the transformer since it is working the fan relay. This is an old unit and my first step would be check the wiring and connections especially at the limit switch. If you have a VOM (volt ohm meter) see if you have voltage present through the limit. The limit will stop the gas valve from activating. That's the box with a wheel inside of it with temps stamped on it. If there is no voltage there disconect the white wire coming from the thermostat and see if you have 24 volts there. If no voltage there you have a wire problem or a bad t-stat. Remove the thermostat from the sub base and jump a wire between the white and red wire. If the unit fires you have a bad t-stat. Hope this helps.