It's dated 1987. I took it out of it's original unopened box. Getting 12 V to it. It's the same as the one that it replaced. Both have the same electrical plug. That wiring ran the furnace that I removed. I'm thinking that the problem is the control board. What else could it be? Bob Dunahugh
New Old Stock Suburban furnace will not run at all
- Thread starter Bob Dunahugh
- Start date
Bob,
I'm thinking a capacitor in on the control board is bad. Likely in a delay ON timing circuit, but I don't have a schematic for it. Electrolytic
capacitors are akin to wet cell batteries, the electrolyte dries out over the years. If you have a local electronics shop you can have them replace
all the capacitors, or maybe you are handy with a soldering iron yourself... capacitors are not expensive.
Otherwise order a replacement board. Dinosaur Electronics is likely your best bet for a replacement.
--
Bruce Hislop
ON Canada
77PB, 455 Dick P. rebuilt, DynamicEFI EBL EFI & ESC.1 ton front end
http://www.gmcmhphotos.com/photos/showphoto.php?photo=29001
My Staff says I never listen to them, or something like that
I'm thinking a capacitor in on the control board is bad. Likely in a delay ON timing circuit, but I don't have a schematic for it. Electrolytic
capacitors are akin to wet cell batteries, the electrolyte dries out over the years. If you have a local electronics shop you can have them replace
all the capacitors, or maybe you are handy with a soldering iron yourself... capacitors are not expensive.
Otherwise order a replacement board. Dinosaur Electronics is likely your best bet for a replacement.
--
Bruce Hislop
ON Canada
77PB, 455 Dick P. rebuilt, DynamicEFI EBL EFI & ESC.1 ton front end
http://www.gmcmhphotos.com/photos/showphoto.php?photo=29001
My Staff says I never listen to them, or something like that
If the furnace fan runs when the thermostat calls for heat, but the burner
fails to light, a few things might be wrong.
FIRST, check voltage of your power source.
if it is low, fan speed will be low and sail switch in the housing
will not close, resulting in no voltage to the ignition.
SECOND, check propane supply, hoses, shut off valves, regulator, and
pressure end to end.
THIRD, check flame presence sensor. It senses presence of propane flame
(ionized particles that conduct electricity) It will close propane
regulator valve(s) if no flame present.
Jim Hupy
> Bob,
>
> I'm thinking a capacitor in on the control board is bad. Likely in a delay
> ON timing circuit, but I don't have a schematic for it. Electrolytic
> capacitors are akin to wet cell batteries, the electrolyte dries out over
> the years. If you have a local electronics shop you can have them replace
> all the capacitors, or maybe you are handy with a soldering iron
> yourself... capacitors are not expensive.
>
> Otherwise order a replacement board. Dinosaur Electronics is likely your
> best bet for a replacement.
> --
> Bruce Hislop
> ON Canada
> 77PB, 455 Dick P. rebuilt, DynamicEFI EBL EFI & ESC.1 ton front end
> http://www.gmcmhphotos.com/photos/showphoto.php?photo=29001
> My Staff says I never listen to them, or something like that
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
fails to light, a few things might be wrong.
FIRST, check voltage of your power source.
if it is low, fan speed will be low and sail switch in the housing
will not close, resulting in no voltage to the ignition.
SECOND, check propane supply, hoses, shut off valves, regulator, and
pressure end to end.
THIRD, check flame presence sensor. It senses presence of propane flame
(ionized particles that conduct electricity) It will close propane
regulator valve(s) if no flame present.
Jim Hupy
> Bob,
>
> I'm thinking a capacitor in on the control board is bad. Likely in a delay
> ON timing circuit, but I don't have a schematic for it. Electrolytic
> capacitors are akin to wet cell batteries, the electrolyte dries out over
> the years. If you have a local electronics shop you can have them replace
> all the capacitors, or maybe you are handy with a soldering iron
> yourself... capacitors are not expensive.
>
> Otherwise order a replacement board. Dinosaur Electronics is likely your
> best bet for a replacement.
> --
> Bruce Hislop
> ON Canada
> 77PB, 455 Dick P. rebuilt, DynamicEFI EBL EFI & ESC.1 ton front end
> http://www.gmcmhphotos.com/photos/showphoto.php?photo=29001
> My Staff says I never listen to them, or something like that
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
I just bought a Suburban control board on Amazon for Bill Bramlett. They have a universal board made by Suburban which was about $15 less than the Dinosaur board. It worked well but he had to drill one new mounting hole. It fits about a dozen different Suburbans.
Emery Stora
77 Kingsley
Frederick, CO
>
> Bob,
>
> I'm thinking a capacitor in on the control board is bad. Likely in a delay ON timing circuit, but I don't have a schematic for it. Electrolytic
> capacitors are akin to wet cell batteries, the electrolyte dries out over the years. If you have a local electronics shop you can have them replace
> all the capacitors, or maybe you are handy with a soldering iron yourself... capacitors are not expensive.
>
> Otherwise order a replacement board. Dinosaur Electronics is likely your best bet for a replacement.
> --
> Bruce Hislop
> ON Canada
> 77PB, 455 Dick P. rebuilt, DynamicEFI EBL EFI & ESC.1 ton front end
> http://www.gmcmhphotos.com/photos/showphoto.php?photo=29001
> My Staff says I never listen to them, or something like that
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
Emery Stora
77 Kingsley
Frederick, CO
>
> Bob,
>
> I'm thinking a capacitor in on the control board is bad. Likely in a delay ON timing circuit, but I don't have a schematic for it. Electrolytic
> capacitors are akin to wet cell batteries, the electrolyte dries out over the years. If you have a local electronics shop you can have them replace
> all the capacitors, or maybe you are handy with a soldering iron yourself... capacitors are not expensive.
>
> Otherwise order a replacement board. Dinosaur Electronics is likely your best bet for a replacement.
> --
> Bruce Hislop
> ON Canada
> 77PB, 455 Dick P. rebuilt, DynamicEFI EBL EFI & ESC.1 ton front end
> http://www.gmcmhphotos.com/photos/showphoto.php?photo=29001
> My Staff says I never listen to them, or something like that
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
As stated. No fan, nothing. As an over the top person on maintenance. I had replace the working board in the GMC that burned about 9 years ago. I kept that used board for that. Just in case situation. Now I'm at that . Just in case. So since nothing is turning on. There's a delay relay that must energize before the fan can come on. That's starting to look like the problem. ? Bob Dunahugh
________________________________
From: Bob Dunahugh
Sent: Tuesday, September 18, 2018 2:19 AM
To: gmclist
Subject: New Old Stock Suburban furnace will not run at all
It's dated 1987. I took it out of it's original unopened box. Getting 12 V to it. It's the same as the one that it replaced. Both have the same electrical plug. That wiring ran the furnace that I removed. I'm thinking that the problem is the control board. What else could it be? Bob Dunahugh
________________________________
From: Bob Dunahugh
Sent: Tuesday, September 18, 2018 2:19 AM
To: gmclist
Subject: New Old Stock Suburban furnace will not run at all
It's dated 1987. I took it out of it's original unopened box. Getting 12 V to it. It's the same as the one that it replaced. Both have the same electrical plug. That wiring ran the furnace that I removed. I'm thinking that the problem is the control board. What else could it be? Bob Dunahugh
I'm with Jim. I'm thinking low voltage and sail switch. I would start the engine which should bring the charging voltage up to around 14.0 volts.
Then try starting the furnace and see if the extra voltage makes any difference.
Also read the voltage right at the furnace and get your ground right at the furnace. Now what voltage do you have? If it does not match closely the
voltage at the house battery then you have some loss on either the hot or ground side. Go find it.
After that I am with Bruce. Start replacing electrolytic capacitors.
--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
Then try starting the furnace and see if the extra voltage makes any difference.
Also read the voltage right at the furnace and get your ground right at the furnace. Now what voltage do you have? If it does not match closely the
voltage at the house battery then you have some loss on either the hot or ground side. Go find it.
After that I am with Bruce. Start replacing electrolytic capacitors.
--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
When you start the furnace. The blower comes on first. As I said. Nothing. No fan operation. Voltage at the furnace is at 13.1 volts. There's a delay relay that the thermostat turns on. That relay then turns the fan on first. And energizes he control board. The sail switch senses fan operation. So it can't be the sail switch. As the fan never turns on for the sail switch to sense. Bob Dunahugh
________________________________
From: Bob Dunahugh
Sent: Tuesday, September 18, 2018 5:09 PM
To: gmclist
Subject: RE: New Old Stock Suburban furnace will not run at all
As stated. No fan, nothing. As an over the top person on maintenance. I had replace the working board in the GMC that burned about 9 years ago. I kept that used board for that. Just in case situation. Now I'm at that . Just in case. So since nothing is turning on. There's a delay relay that must energize before the fan can come on. That's starting to look like the problem. ? Bob Dunahugh
________________________________
From: Bob Dunahugh
Sent: Tuesday, September 18, 2018 2:19 AM
To: gmclist
Subject: New Old Stock Suburban furnace will not run at all
It's dated 1987. I took it out of it's original unopened box. Getting 12 V to it. It's the same as the one that it replaced. Both have the same electrical plug. That wiring ran the furnace that I removed. I'm thinking that the problem is the control board. What else could it be? Bob Dunahugh
________________________________
From: Bob Dunahugh
Sent: Tuesday, September 18, 2018 5:09 PM
To: gmclist
Subject: RE: New Old Stock Suburban furnace will not run at all
As stated. No fan, nothing. As an over the top person on maintenance. I had replace the working board in the GMC that burned about 9 years ago. I kept that used board for that. Just in case situation. Now I'm at that . Just in case. So since nothing is turning on. There's a delay relay that must energize before the fan can come on. That's starting to look like the problem. ? Bob Dunahugh
________________________________
From: Bob Dunahugh
Sent: Tuesday, September 18, 2018 2:19 AM
To: gmclist
Subject: New Old Stock Suburban furnace will not run at all
It's dated 1987. I took it out of it's original unopened box. Getting 12 V to it. It's the same as the one that it replaced. Both have the same electrical plug. That wiring ran the furnace that I removed. I'm thinking that the problem is the control board. What else could it be? Bob Dunahugh
Bob,
If the fan won't even run and you've installed your spare board with the same result, I'd test the fan motor next. Disconnect the fan wires and
connect battery voltage to it and see if it runs. If it doesn't run, spin the fan a few times as the commutator may have oxidized from sitting for
many years.
If it does run, then you are back to a board problem. You should hear the motor relay "Click" after the startup delay.
Also, if you have been testing it with the coach wiring, check to be sure the thermostat is actually switching. Try connecting the thermostat wires
together right at the furnace to bypass the thermostat.
If you have power at the furnace and the thermostat wires connected together and still get no action from the board (relay click) then you must have 2
bad boards.
Just what I would do to troubleshoot.
--
Bruce Hislop
ON Canada
77PB, 455 Dick P. rebuilt, DynamicEFI EBL EFI & ESC.1 ton front end
http://www.gmcmhphotos.com/photos/showphoto.php?photo=29001
My Staff says I never listen to them, or something like that
If the fan won't even run and you've installed your spare board with the same result, I'd test the fan motor next. Disconnect the fan wires and
connect battery voltage to it and see if it runs. If it doesn't run, spin the fan a few times as the commutator may have oxidized from sitting for
many years.
If it does run, then you are back to a board problem. You should hear the motor relay "Click" after the startup delay.
Also, if you have been testing it with the coach wiring, check to be sure the thermostat is actually switching. Try connecting the thermostat wires
together right at the furnace to bypass the thermostat.
If you have power at the furnace and the thermostat wires connected together and still get no action from the board (relay click) then you must have 2
bad boards.
Just what I would do to troubleshoot.
--
Bruce Hislop
ON Canada
77PB, 455 Dick P. rebuilt, DynamicEFI EBL EFI & ESC.1 ton front end
http://www.gmcmhphotos.com/photos/showphoto.php?photo=29001
My Staff says I never listen to them, or something like that
Check the thermostat and it’s wiring.
Rick “ask me how I know” Denney
> As stated. No fan, nothing. As an over the top person on maintenance. I
> had replace the working board in the GMC that burned about 9 years ago. I
> kept that used board for that. Just in case situation. Now I'm at that .
> Just in case. So since nothing is turning on. There's a delay relay that
> must energize before the fan can come on. That's starting to look like the
> problem. ? Bob Dunahugh
>
> --
Rick Denney
73 x-Glacier 230 "Jaws"
Off-list email to rick at rickdenney dot com
Rick “ask me how I know” Denney
> As stated. No fan, nothing. As an over the top person on maintenance. I
> had replace the working board in the GMC that burned about 9 years ago. I
> kept that used board for that. Just in case situation. Now I'm at that .
> Just in case. So since nothing is turning on. There's a delay relay that
> must energize before the fan can come on. That's starting to look like the
> problem. ? Bob Dunahugh
>
> --
Rick Denney
73 x-Glacier 230 "Jaws"
Off-list email to rick at rickdenney dot com
I had used my OHM meter at the furnace to test the thermostat/wire. That was fine. Had done the spin the motor trick. I'm not hearing the relay click. So I thinking it's the delay relay. Heading to Amana today. A long 1 hour drive. If I replace the relay. I'll replace the board at the same time. I do want to know what's wrong. It's not much money to replace both. Then I'll end up with a good used board or relay for someone. We'll talk on this when we get back. Bob Dunahugh
________________________________
From: Bob Dunahugh
Sent: Wednesday, September 19, 2018 1:42 AM
To: gmclist
Subject: RE: New Old Stock Suburban furnace will not run at all
When you start the furnace. The blower comes on first. As I said. Nothing. No fan operation. Voltage at the furnace is at 13.1 volts. There's a delay relay that the thermostat turns on. That relay then turns the fan on first. And energizes he control board. The sail switch senses fan operation. So it can't be the sail switch. As the fan never turns on for the sail switch to sense. Bob Dunahugh
________________________________
From: Bob Dunahugh
Sent: Tuesday, September 18, 2018 5:09 PM
To: gmclist
Subject: RE: New Old Stock Suburban furnace will not run at all
As stated. No fan, nothing. As an over the top person on maintenance. I had replace the working board in the GMC that burned about 9 years ago. I kept that used board for that. Just in case situation. Now I'm at that . Just in case. So since nothing is turning on. There's a delay relay that must energize before the fan can come on. That's starting to look like the problem. ? Bob Dunahugh
________________________________
From: Bob Dunahugh
Sent: Tuesday, September 18, 2018 2:19 AM
To: gmclist
Subject: New Old Stock Suburban furnace will not run at all
It's dated 1987. I took it out of it's original unopened box. Getting 12 V to it. It's the same as the one that it replaced. Both have the same electrical plug. That wiring ran the furnace that I removed. I'm thinking that the problem is the control board. What else could it be? Bob Dunahugh
________________________________
From: Bob Dunahugh
Sent: Wednesday, September 19, 2018 1:42 AM
To: gmclist
Subject: RE: New Old Stock Suburban furnace will not run at all
When you start the furnace. The blower comes on first. As I said. Nothing. No fan operation. Voltage at the furnace is at 13.1 volts. There's a delay relay that the thermostat turns on. That relay then turns the fan on first. And energizes he control board. The sail switch senses fan operation. So it can't be the sail switch. As the fan never turns on for the sail switch to sense. Bob Dunahugh
________________________________
From: Bob Dunahugh
Sent: Tuesday, September 18, 2018 5:09 PM
To: gmclist
Subject: RE: New Old Stock Suburban furnace will not run at all
As stated. No fan, nothing. As an over the top person on maintenance. I had replace the working board in the GMC that burned about 9 years ago. I kept that used board for that. Just in case situation. Now I'm at that . Just in case. So since nothing is turning on. There's a delay relay that must energize before the fan can come on. That's starting to look like the problem. ? Bob Dunahugh
________________________________
From: Bob Dunahugh
Sent: Tuesday, September 18, 2018 2:19 AM
To: gmclist
Subject: New Old Stock Suburban furnace will not run at all
It's dated 1987. I took it out of it's original unopened box. Getting 12 V to it. It's the same as the one that it replaced. Both have the same electrical plug. That wiring ran the furnace that I removed. I'm thinking that the problem is the control board. What else could it be? Bob Dunahugh
