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?
1. 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....
2. 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???
3. 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
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....