Sorry to drag up an old thread, but my furnace is having the exact same issue and i was wondering if you ever fixed it. Runs fine to start then after a few minutes it starts clicking like crazy then the flame shuts off and wont restart. Thanks for any info.

 

Beenthere; he would only do that once -using 24v for 120v. It would have a flashbulb effect. The older "glowplugs" on some gas fired water water heaters did glow orange, but the newer HSI's for furnaces seem to be much brighter -as in white hot. You might check your power .ie 120 vac and breakers -15-20 amps-. Do you have a lazy breaker? Are you sure that only the furnace is on the breaker as in a dedicated circuit ?? If your circuit is loaded to or over max and all the lights/appliances start simultainiously the overload condition could cause many strange things to happen. Pumps, furnaces, a/c compressers, Electric water heaters, microwaves, electric ranges, refrigerators, washer and dryers, and kitchen outlets among others should all be on dedicated circuits.

 

A. That jbox trouble with blowing fuses could be causing troubles with the furnace.

B. Are you sure your using the right voltage ignitors/HSI's(as in not using 24 volt ones on a 120 volt system).

 

not that i can remember. no electrical work has been done in anyway in some years. I put a jbox in to a hot water heater in 05 but that was it. Now that jbox has had some issues lately. I dont know why but it went through 2 fuses in 2 weeks. I had to keep flippin it off and flippin it back on becuase my hot water was not working. Thats the only noteable thing lately. I really should hard wire the tank in and remove the jbox since it does go to my breaker box in the house but its worked fine for 3+ yrs this way.

*note - my igniter still will not glow orange. Its receiving power but the the gas just comes on for a second and shuts off....3 times lock out failure 2 red flashes.

 

Was any electrical work done shortly before it started having trouble.
Including any electrical work that may have been done late spring or summer.
Weather it had to do with your heating or cooling system is not important.

 

wow this is all great information - i will have to check it out tonight for sure.

I guess I should verify that the unit doesnt always fire up the first time and run through a full cycle. Just sometimes it actually works. Most of the time it comes on and gives me the ready for heat flashing light and just fails to lockout code. No other code comes on unless I remove and replace the pc board with another like board. I than do not ever get the ready for heat light and instead only get the 5 flashing red lights...

 

ThomasV, Pay close attention to what Houston204 has said. The public in general has been duped into thinking if something doesn't work
then you have to replace a part, but it doesn't work that way any more particularly with all the hi-tech electronics in everything. When I
first read your thread, the very first thing that came to mind was "Did you check your system (in this case -furnace-) ground?" Not the
120 & nuetral coming to the unit, but the ground continuity between PC boards, the furnace cabinet, valves, blowers, everything. New
appliances directly from the manufacturer can have a ground continiuty problem just because of a little to much overspray when they paint
the parts or maybe there is a sheet metal screw that didn't cut through the paint to bare metal. The fact that the furnace seems to work
correctly for the first firing cycle BEFORE it displays some form of failure indicates to me that the problem is most likely heat related. Check
around the firebox area, the ground lead(s) from the PC board to the cabinet, check the burners themselves to make sure every place metal
touches metal it is clean and bright. 80 cents worth of sandcloth is worth more than a new furnace.

 

If you hear the gas valve clicking when it doesn't light. Then its probably not a pressure switch problem.

 

i second the pressure switch idea once it pulls in you could jump it to see if the flames stay on. or attach your meter to it with alligator clips while leaving thefurnace wireing in place and see if its dropping out

 

Turn off power to your furnace and remove and clean the control board connections to the furnace body (ground). Dirt can cause a faulty connection creating a flame sensor lockout.
Also verify that the field installed ground wire connection is clean and making agood connection.

If you reset power and watch the furnace untill lockout occurs, do any other error codes appear before your 2 flashes?

 

Bouwwhuis2000 - I will test that later on tonight to see what the meter reads - I know that if i touch the lead and ground myself out it kicks on the blower motor.

Tator1076 - where is this limit switch? are you referring to the HI and low? 145-40 or 45 or whatever... the texas instrument labeled P15? With 2 wires going into it? if so yes. If you're referring to something else the answer is likely no.

H. Phillips - Yes, the gas valve clicks. In fact, when it fails it starts clicking a bunch. I too suspected the pressure switch may be failing, that or it could simply be clogged. I want to replace it but cannot find anyone who will sell it to me. When I get home I will tap on it to see what it does.

 

Is the gas valve clicking? Did you tap the pressure switch to see if it would make the flame drop out for an instant? I had a similar problem and replacing the pressure switch did the trick. The Trane rep said they hardly ever break and suggested I replace the gas valve, but breethere put me on the right track.

 

Did you check limit switch? Note replacing the flame sensor is some what wrong. You just need to clean it every year with a dollar bill. I only change them when its never been clean and the furnace is over 6 years old.

 

I know how you feel with the intermittent furnace problem.
I have experienced the same frustration.

If you have a meter with a 50 micro-amp scale you can confirm if the flame sensor is delivering 1-2 uA of current with flame. If the sensor has just a single wire, you can hook up the meter in series with the feeder wire. Red meter lead to the sensor, black to the wire. No flame = no current.
If the board does not see the current within a short time, it will turn the gas off.

I'm no expert but I am learning.