Wiring Diagram for Gas Hung Heater

I've got a Dayton gas heater. I had the repair guy come out last night
to light the pilot light (well, to figure out _why_ the pilot light
wasn't coming on).
After we got the pilot light sorted (it was clogged) we fired the thing
up and determined that the fan switch isn't working. So, I went out
today and got a new fan switch, and replaced the old one.
It _still_ doesn't work, but I can hear a distinct "click" from the
heater when the fan switch _should_ be working. But the fan doesn't come
on until the limit switch engages and turns the gas off. So I suspect
that my new fan switch is working just fine, but there's something else
wrong with the unit.
Given that the former owner of the property would have enthusiastically
torn into this thing either to fix it or "improve" it, I can't count on
things just being broken -- I have to accept the fact that things may be
put together wrong, etc.
So -- my Google Fu completely failed me in turning up a service manual or
schematic for this thing. Can anyone point me to a wiring diagram?
Failing that, can anyone give me a rundown on how these things go
together, where to find the limit switch, and that sort of nifty stuff?
Am I correct in assuming that if I identify the 120V wires across the fan
switch and simply short them out, that the fan should come on? For that
matter, I assume that with the fan _off_ I should see 120V across the
appropriate terminals of the fan switch? (I'm suspecting broken or
incorrect wiring here, which is why I'm asking these questions).
Thanks in advance.
Reply to
Tim Wescott
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Does the limit switch have open terminal? Sounds like the fan is wired to high cut off, rather than wired to fan.
Christopher A. Young Learn more about Jesus
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I've got a Dayton gas heater. I had the repair guy come out last night to light the pilot light (well, to figure out _why_ the pilot light wasn't coming on).
After we got the pilot light sorted (it was clogged) we fired the thing up and determined that the fan switch isn't working. So, I went out today and got a new fan switch, and replaced the old one.
It _still_ doesn't work, but I can hear a distinct "click" from the heater when the fan switch _should_ be working. But the fan doesn't come on until the limit switch engages and turns the gas off. So I suspect that my new fan switch is working just fine, but there's something else wrong with the unit.
Given that the former owner of the property would have enthusiastically torn into this thing either to fix it or "improve" it, I can't count on things just being broken -- I have to accept the fact that things may be put together wrong, etc.
So -- my Google Fu completely failed me in turning up a service manual or schematic for this thing. Can anyone point me to a wiring diagram? Failing that, can anyone give me a rundown on how these things go together, where to find the limit switch, and that sort of nifty stuff?
Am I correct in assuming that if I identify the 120V wires across the fan switch and simply short them out, that the fan should come on? For that matter, I assume that with the fan _off_ I should see 120V across the appropriate terminals of the fan switch? (I'm suspecting broken or incorrect wiring here, which is why I'm asking these questions).
Thanks in advance.
Reply to
Stormin Mormon
Dayton is a house brand for Grainger's. See if they still have the manual on file.
Reply to
Michael A. Terrell
enthusiastically
Check the flame sensor.
Reply to
PrecisionmachinisT
enthusiastically
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Reply to
PrecisionmachinisT
enthusiastically
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Sounds like you have stabding pilot system.
Reply to
PrecisionmachinisT
The fan is SUPPOSED to come on if the high limit cut off activates.
enthusiastically
Reply to
PrecisionmachinisT
Calls for heat flame comes on high limit turns flame off fan comes on
And you suggest to check the flame sensor? I think we view things differently.
Christopher A. Young Learn more about Jesus
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Check the flame sensor.
Reply to
Stormin Mormon
Sound like you gad a code id yor dose? Stabding pilot?
Hmm. What makes you think his device has a standing pilot? Same thing told you to check the flame sensor? Which I doubt it has one, other than a thermocouple.
Christopher A. Young Learn more about Jesus
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Sounds like you have stabding pilot system.
Reply to
Stormin Mormon
High limit cut off is supposed to turn off the burner. This is a safety design. Normally, a high limit cut off will never get used. Only if the fan is not running for some reason.
Fan comes on, at a lower setting. This is how the furnace operates, normally.
We sure learned different information. Me, I think you're mistaken.
Christopher A. Young Learn more about Jesus
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The fan is SUPPOSED to come on if the high limit cut off activates.
Reply to
Stormin Mormon
The limit switch also turns the fan on , and it's temperature-adjustable . Look for little adjustable pointers on the face that rotates ... one's for the fan , one's for gas valve hi temp cutoff . It could also be the relay that powers the fan , which is energized by the limit switch .
Reply to
Snag
The author of this web page has not inspired my confidence.
Christopher A. Young Learn more about Jesus
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Sounds like you have stabding pilot system.
Reply to
Stormin Mormon
(top posting fixed)
The service guy told me that the limit switch both turns the burner off, and forces the fan to turn on, so that the heat exchanger gets some cooling if the fan switch is broken.
So the behavior is normal for a broken fan switch -- it's just that fixing the fan switch doesn't fix the @$#% behavior.
Reply to
Tim Wescott
I couldn't find it on their web page. Suggestions?
Reply to
Tim Wescott
I dunno if there is one -- I'm told the fan switch is a time delay gizmo.
Reply to
Tim Wescott
Email? Snail mail? Phone call? They have very little tech data on their website.
Reply to
Michael A. Terrell
That would mean it gets power when the flame comes on The delay is so that it warms up some and doesn't blow cold air.
There can't be a lot involved in wiring the switch to fan. Check for continuity and power.
-jim
Reply to
jim
Yea, I think it's down to that. I really prefer to have a schematic. Even if it's wrong, if it's Official it makes me feel better -- kind of like having my favorite blanky, I guess.
Reply to
Tim Wescott
Ha. That got me going. At least it showed me the general direction of where to look for the limit switch (the wiring of which was hidden).
It must have been a loose connection, because after I went into Full Engineer Mode and measured everything every which way with my voltmeter, then took a couple of connections apart to visually inspect them (without finding problems), it worked fine when I turned it on again to look for problems.
So -- a qualified yippie. I never like problems that go away by themselves; I'm always afraid they're just sleeping and not dead.
Reply to
Tim Wescott
enthusiastically
If the flame stays lit till the exchanger overheats then the flame sensor is okay.
There may be a second Klixon to delay the fan till the exchanger warms up.
As long as your high limit is killing the gas like it should then you should be able to get by until you properly troubleshoot the unit by forcing the fan to operate by jumpering connecting G to W
Just beware that if you do this, the burner will also operate if you turn the thermostat to "fan only"
Reply to
PrecisionmachinisT

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