I have a older robertshaw vh 700 furnace in the basement. I can light the pilot and it stays on I turn the valve to the on position. Turn up the thermostat and nothing happens. There is no copper thermo coupling, but there are wires running from the pilot light to the gas valve, I believe it's a millivolt pilot sensor, I've tried bypassing the thermostat basically jumping the two wires,(nothing) there is a wire coming out of the electrical box that's probably from a transformer, I will be investigating a little later today. How much voltage should there be going to the thermastat and then back to the gas valve in order to open the gas valve? Is there anyway of testing the gas valve? And lastly if it seems to be the likely cause where would I be able to purchase a tranformer?
Thanks in advance

Sat. Jan 12th 2012 07:10

Robertshaw doesn't make furnaces. You have a partial model number for the furnace gas valve.

There should be an additional three digits to the model number that are needed to identify the voltage the gas valve uses. See if you can get the complete model number.