Inducer Motor won't Start

[Jeff B]

I have a Comfortmaker Furnace (guessing 10 years old) with a Honeywell SV 9541 Smart Valve. Furnace would not turn on in Heat mode. Ruled out thermostat and inducer fan so changed out the Honeywell unit with another one. Previous Honeywell Unit hand solid Green indicator which does not match ANY error code. New valve has 3 Flash Error. As experiment, I powered the Inducer fan directly, forcing it on. After 20-30 seconds the furnace fires up, main fan comes on and furnace heats as normal - indicator light at that time has the constant flash indicating normal operation. After Wiring back to normal same result - no cycle, no vent fan, 3 flash error.

[heatseeker]

sounds like a loose connection or open switch assuming you have the correct circuit board,

[Jeff B]

Its been working for a decade prior so everything is correct. I replaced the Honeywell SV9541 with an identical unit. I have 120 going into the smart valve for the Inducer, The valve is supposed to switch on the inducer through the 4-pin connector, but it is not (2 different Honeywell units with the same result). Pressure switch functions if I force power to the Inducer (bypassing the smart valve) and the furnace "comes to life". Just can't get the smart valve to send the power to the inducer.

[Freon]

In the installation instructions (*.*/techlit/pdf/69-0000s/69-1059.pdf), what figure describes how you have the valve wired... Fig. 7, Fig.8, or Fig.* How do you have the Ignition System Control Switch set (page 9)*

[Jeff B]

Thanks for your help! Setup is represented by Figure 7. Ignition Control Switch is set to On position.

[Freon]

If you look at the flow chart on pg 11, you'll see the first test is to see if the pressure switch is open. If it's closed, for whatever reason, the inducer will not come on. Try disconnecting the pressure switch so it's forced open and see if the inducer comes on.

Check that all plugs between the valve and fan control board are well-seated.