We have an intermittent problem where the furnace blower blows cold air, the pilot light igniter and pilot light are on, and the thermostat is calling for heat. The problem is the same with a new thermostat. The thermostat wiring resistance is OK. The furnace is a 5-year old Comfortmaker GNE100F14A1 (Honeywell control board and SV9500 gas valve). In an effort to localize the problem between the gas valve or control board, I am currently observing voltages on the gas valve wires (the pressure valve and switch are OK as is the voltage .. unplug this and both pilot and main burner go off), so I am watching the orange signal wire voltage when the problem recurs (every 3-4 days). Thanks in advance for your help. Also, do you know how I can obtain a detailed circuit diagram of the control board? 5/6/04

-- Tom Plath (tgplath@yahoo.com), May 06, 2004

Answers

Tom! When this is happenin try disconnectin the RED wire from the circuit board. This wire carrys 24 volts to the t-stat. If the problem is solved then--check the t-stat wirin. Especially the RED and WHITE wires. [White is the heatin circuit, Green is Fan and yellow is a/c]

If it doesn't change anything you have problems in the puter and probably will need a new one. Obtainin a schmetic of the board will probably be very difficult if not impossible. I never could get on-- new boards are for sale--. Greed is the name of the game. Let me know how tings turns out. old hoot. Matt. 24:44

-- oldhootgibson (oldhoot@shawneelink.net), May 06, 2004.