my 10 year old gas fireplace has recently given me trouble with turning on and off. when I moved here, the house had a simple wall switch that turned the fireplace on and off. I subsequently wired an inexpensive manual thermostat in series with the switch. Thus, the switch was the master control - ON had the tstat controlling the fireplace. OFF was off ;) it has worked well for 1.5 years.....
anyway, problem with intermittent no-start. I take my first look under the fireplace and the wiring was a joke. It is some kind of braided/insulated single strand copper stuff running all over the place. a basic on/off switch in the middle with a bunch of stuff taped and jigged up....not good. I noticed that jiggling the wires from the hi-limit switch caused the fire to jump. In the end I got brave and removed much of the old, brittle wiring and am left with a bare gas valve and two wires from what I think to be a dead hi-limit switch. I removed all of the excess wire that was wrapped around the gas lines and in behind the blower for no reason....
right now I've got the pair of tstat/switch wires (from the wall) directly jumpered to the two terminals on the gas valve, and the unit works perfectly. switches on and off instantly.....having traced the wiring diagram several times, all I can see is they had the hi-limit switch and a microsswitch inline....am I missing something here?
questions:
- the high limit switch shows continuity, yet when wired in series with the gas valve, will not allow the fire to start. huh? Should I not be able to run the high limit switch in series with one side of the tstat control wires (say the white one) and have it work? because it doesn't - yet shows continuity....and then will "sometimes" allow the fire to start....
- the cheep wall thermostat - shows continuity when triggered, and open when not (as you might expect). however, it will NOT turn on the fireplace. If I manually short the leads and get the fire going, it will hold the fire on and turn it off..... again, huh? it workd for over a year perfect...clearly it has failed. didn't know they failed???
- wiring - does any code or anything apply here (Ontario, Canada)? does there have to be a certain style or type of electrical wiring underneath the fireplace? or can I use the simple 16 awg. insulated primary wire (used in car audio) for this app? I'm using it right now for testing with no problems, but don't want to get into a code issue should a problem arise in the future....
I've tried the tstat right at the gas valve (bypassing the wiring in the wall) and it behaves the same. I'm going to get a new digital unit tomorrow, this I know....but does anybody out there have any thoughts on questions 1 and 3? My thinking is bad tstat, and bad hi limit switch mixed with crusty old wiring....
thanks! b