Any HVAC guys?? | GTAMotorcycle.com

Any HVAC guys??

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timtune

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I have a wall mounted direct vent gas heater in my garage. It's about 2 years old. Maybe a month ago it wasn't responding to the thermostat. Pilot on but the heater didn't kick in. Shut it down and started it up again and it worked fine . Yesterday same thing no heat but the pilot is lit. This time shutting down completely and doing the reboot did not work. Suspected the programmable thermostat so I replaced it with the dumb 2 wire bimetal unit that came with the heater. Still nothing.

Thoughts?
 
Is there gas flow to the burner? here is a thermo switch beside the pilot that needs to open when the pilot is lit... so it doesn't just vent gas when the pilot is un-lit.
 
bitzz said:
Is there gas flow to the burner? here is a thermo switch beside the pilot that needs to open when the pilot is lit... so it doesn't just vent gas when the pilot is un-lit.
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I don't know. I can only see through the glass that the pilot is on.
 
How smart is the heater? Does it have a circuit board that flashes trouble codes at you? My guess is it is locking you out due to a sensor issue which is why power cycle temporarily fixed it. It could be pilot Thermopile (creates voltage when hot and that voltage is needed to trigger main gas valve) or it could be flame sensor that wants to sense main fire lit and shuts off gas if it doesn't. The main fire sensor has a bad habit of getting dirty and needing a quick polish (or replacement if a tech wants to pad the bill). I'd be surprised if it was that dirty after such a short time though. When it was installed did tech use a combustion analyzer to confirm proper operation?
 
Is it a Bluetooth thermostat?

We had issues with ours pretty consistently about a year ago. We had to dismount it from where it was and bring it closer to the furnace for it to work.

If you have introduced something into your house that may interrupt the signal that’s likely the cause. You can change channels on some of these things to get around it but we couldn’t seem to get a decent constant signal that way.
 
@jc100 Thermostat was a programable. Changed to a simple mechanical bimetal thermo and that made no difference. @GreyGhost Heater is pretty basic. I do not believe it has any PCBs. Installed about 2 years ago. No idea if they did the combustion analysis. @raginduck Pilot light comes on but the heater doesn't kick in. Nothing pilot just purrs along, no reponse to the thermo set on high. I don't smell gas.

How can I check the pilot thermocouple? I going within some simple for 10 points.
 
GreyGhost said:
How smart is the heater? Does it have a circuit board that flashes trouble codes at you? My guess is it is locking you out due to a sensor issue which is why power cycle temporarily fixed it. It could be pilot Thermopile (creates voltage when hot and that voltage is needed to trigger main gas valve) or it could be flame sensor that wants to sense main fire lit and shuts off gas if it doesn't. The main fire sensor has a bad habit of getting dirty and needing a quick polish (or replacement if a tech wants to pad the bill). I'd be surprised if it was that dirty after such a short time though. When it was installed did tech use a combustion analyzer to confirm proper operation?
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If the pilot stays lit it’s not likely the thermopile, gas valves usually cut all gas including pilot when the thermo fails.

You can test by wit a meter. Set to millivolts dc, one less to the button on below the screw in coupling, thd other on the copper sheath. Use a lighter or torch to excite the thermopile, 15-35mv is good. Check for corrosion on the contact point, they should be shiny clean.

If it fires than shuts off for a few minutes, that’s usually a dirty flame sensor. Find it, wipe the glass with a damp cloth. If it doesn’t fire at all, this is not likely the problem.
 
Mad Mike said:
If it doesn’t fire at all, this is not likely the problem.
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I hear nothing. I don't think it's firing at all. I'll see if I can test that TC.
 
Next is to check the limit switch. It keeps the fan and stat timing for the blower, it also acts a a safety if the furnace gets too hot. If it’s failed open, the furnace will not start.
 
@timtune cam you post a pick of wiring diagram? Normally inside a cover (or post make and model number). We are all shooting in the dark here (although some decent ideas). It could be many things including a blown rollout fuse if wind pushed the flame back into the cabinet.
 
Heres some pics. I can't find a thermodisc. Jumping those two wires to the tstat should kick on the burner if the problem was the tstat Correct?
IMG_1105.JPGIMG_1116.JPG
 
White wire is probably thermopile for pilot sensing. Black wire is flame sensor for main burner. Is red wire power? Crap installation if so. Is fat black wire going to thermostat? I don't see a transformer. Is this a line voltage thermostat?

Does this thing have power? No power could give you pilot but nothing else.
 
timtune said:
Heres some pics. I can't find a thermodisc. Jumping those two wires to the tstat should kick on the burner if the problem was the tstat Correct?
View attachment 66890View attachment 66891
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First make sure all connections are tight, If you
remove the blue marrets and twist the black wires together, that will bypas the TStat. If burner lights you have a bad TStat or TStat wire issue.(loose connection, broken wire)

I would also just wire TStat wires right to gas valve, not sure why they added those little black pieces and marrets.
 
Have you checked youtube at all. It's amazing what informative stuff you can find there.
What kind of maintenance does this require, maybe a sensor needs to be cleaned, or if it exhaust some water, needs to be cleared.
 
Also Timtune, both your photos show gas valve off or in pilot only mode..

Once you light pilot, and pilot is holding you have to rotate black knob to “on”for unit to work.
 
Plugs into 110V but thats mainly for the fan I thought.

If jumping the Tstat doesn't work, then call the The Guy???
 
Kawyman said:
Also Timtune, both your photos show gas valve off or in pilot only mode..

Once you light pilot, and pilot is holding you have to rotate black knob to open for unit to work.
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Yes. I did have it on ON and nothing. I've turned it OFF since it's not working.
 
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