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| Re: [GMCnet] 78 Royale Suburban furnace not lighting burner [message #265838 is a reply to message #265834] |
Tue, 11 November 2014 03:39   |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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Look at the sail switch first. I once moved a Royale in the middle of December and it had the same problem. I had no heat for 5 days. When I arrived at my destination a local guy said simply kick it. He did and the sail switch transferred causing the heat to turn on.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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| Re: [GMCnet] 78 Royale Suburban furnace not lighting burner [message #265840 is a reply to message #265834] |
Tue, 11 November 2014 07:04 |
77Royale
Messages: 461
Registered: June 2014
Location: Mid Michigan
Karma: 6
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Senior Member |
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Id also make sure you have the easy stuff covered. Propane in the tank, Both service valve and gas valve on the furnace are open. And you have enough power. I had low coach batteries which would make the blower run, but not enough juice to get the burner lit. I pluggged into shore power and it fired right up.
77 Royale, Rear Dry Bath. 403, 3.55 Final Drive, Lenzi goodies, Patterson carb and dizzy.
Mid Michigan
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| Re: [GMCnet] 78 Royale Suburban furnace not lighting burner [message #265866 is a reply to message #265845] |
Tue, 11 November 2014 15:33 |
Hal StClair
Messages: 971
Registered: March 2013
Location: Rio Rancho NM
Karma: -12
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Agree with Jim's response completely. I've had the same issue in SOB's before. On a particularly troublesome intermittent heater problem, I intercepted the sail switch and brought the leads out to a simple switch to test the theory (of a sail switch problem). I don't recommend keeping the switch as a permanent fix, but it can narrow the possibilities down for repairs.
Hal
"I enjoy talking to you. Your mind appeals to me. It resembles my own mind, except you happen to be insane."
1977 Royale 101348,
1977 Royale 101586, Diesel powered,
1974 Eagle Bus 45',w/slideout,
Rio Rancho, NM
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| Re: [GMCnet] 78 Royale Suburban furnace not lighting burner [message #265872 is a reply to message #265865] |
Tue, 11 November 2014 16:10 |
Bob de Kruyff
Messages: 4260
Registered: January 2004
Location: Chandler, AZ
Karma: 1
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BobDunahugh wrote on Tue, 11 November 2014 14:24
I used the stove top burners to purge the lines. Checked the voltage. That was good. The blower speed, and flow seemed normal. Let the blower run for some time. Didn't check the sail switch yet. Thanks for your help. Bob Dunahugh USMC
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It's also common for the burners to light monentarily and then shut off since the thermocouple above the flame is not sensing that it lit. They sometimes need to be cleaned and gapped so that the flame will stay on.
Bob de Kruyff
78 Eleganza
Chandler, AZ
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| Re: [GMCnet] 78 Royale Suburban furnace not lighting burner [message #265892 is a reply to message #265872] |
Tue, 11 November 2014 20:42 |
powerjon
Messages: 2446
Registered: January 2004
Karma: 5
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It is common for the ignitor plug and sail switch to be change at the same time, cost is reasonable at less than $40 for both.
JR Wright
78 Buskirk Stretch
75 Avion
Michigan
> On Nov 11, 2014, at 5:10 PM, Bob de Kruyff wrote:
>
> BobDunahugh wrote on Tue, 11 November 2014 14:24
>> I used the stove top burners to purge the lines. Checked the voltage. That was good. The blower speed, and flow seemed normal. Let the blower
>> run for some time. Didn't check the sail switch yet. Thanks for your help. Bob Dunahugh USMC
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
> It's also common for the burners to light monentarily and then shut off since the thermocouple above the flame is not sensing that it lit. They
> sometimes need to be cleaned and gapped so that the flame will stay on.
> --
> Bob de Kruyff
> 78 Eleganza
> Chandler, AZ
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J.R. Wright
GMC GreatLaker
GMC Eastern States
GMCMI
78 30' Buskirk Stretch
75 Avion Under Reconstruction
Michigan
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| Re: [GMCnet] 78 Royale Suburban furnace not lighting burner [message #265897 is a reply to message #265834] |
Tue, 11 November 2014 21:13 |
Steve
Messages: 506
Registered: September 2013
Location: East Greenville, Pa
Karma: 1
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Bob. I spent bunch of time trouble shooting the suburban furnace in my 78 Royale last year. I had concluded that the gas valve was not opening and found that tapping on the gas supply pipe would get it to light. It was reliable last winter. Recently it would not light again and the tapping did not work. This time I removed the electronic board and unpluggeged the wire harnace several times to clean the electrical contacts. Finished it off with some dielectric Greene and she fired right up.
My lessons learned on the furnace
1. Must have good voltage
2. All connections must be clean and free of any corrosion
3. My fan cage was clogged up with carpet and other fibers from Mr. Mouse. This prevented enough speed and air movement to move the sail switch
4 there is a good troubleshooting guide in the furnace maintenance manual
If you would like to talk through it with someone I would be happy to do that. Just pm me and I will get you my phone number.
1978 GMC Royal
Eastern Pennslyvania
1968 Chevrolet C20 396 Camper Special
1969 Chevrolet C20 Camper Special
1985 Buick Electra Park Avenue
1992 Camaro 25th Anniversary Heretage Edition Black
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| Re: [GMCnet] 78 Royale Suburban furnace not lighting burner [message #265914 is a reply to message #265908] |
Wed, 12 November 2014 07:57 |
sgltrac
Messages: 2797
Registered: April 2011
Karma: 1
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I believe the model info is inside the burner cover plate on the small end of the furnace facing the interior of the coach.
Todd Sullivan
Sully
77 royale
Seattle
> On Nov 11, 2014, at 10:41 PM, Bob Dunahugh wrote:
>
> Went out to the GMC tonight to attack the Suburban furnace. Purged the gas line at the gas shut off valve. Taped the gas pipe next to that gas valve as the unit was being turned on. Checked the voltage and ground connection. Labeled the wires, and pulled the furnace out. Checked the intake, and exhaust tubes. Blower was clean. I'll check the sail switch tomorrow. Now my questions. Were is the model number plate? And were do I get the control board, and other parts I need? May need it working next week on the trip to Chicago. It is just butt cold here tonight. OH. It's so nice to have the GMC in it's own heated indoor spot. Thanks for your help. Bob Dunahugh USMC
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Sully
77 Royale basket case.
Future motorhome land speed record holder(bucket list)
Seattle, Wa.
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| Re: [GMCnet] 78 Royale Suburban furnace not lighting burner [message #265945 is a reply to message #265834] |
Wed, 12 November 2014 19:51 |
Steve
Messages: 506
Registered: September 2013
Location: East Greenville, Pa
Karma: 1
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Senior Member |
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I got a new sail switch on line from PPL Motorhomes. My furnace in my 78 Royale is a Suburban NT30. It is not the original furnace. The original was replaced in 1980 due to a recall on the original furnace. So be careful about the model as you could have the original, or it could have been replaced.
1978 GMC Royal
Eastern Pennslyvania
1968 Chevrolet C20 396 Camper Special
1969 Chevrolet C20 Camper Special
1985 Buick Electra Park Avenue
1992 Camaro 25th Anniversary Heretage Edition Black
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| Re: [GMCnet] 78 Royale Suburban furnace. Need parts info [message #266010 is a reply to message #266003] |
Thu, 13 November 2014 15:33 |
bdub
Messages: 1578
Registered: February 2004
Location: Central Texas
Karma: 5
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Senior Member |
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Bob
If you'll share the details, it might help the next guy that needs it.
Vendor:
Contact Info:
Part #s:
Cost: CB $92, Sail Switch $8
Recomendations:
-----Original Message-----
From: On Behalf Of Bob Dunahugh
Sent: Thursday, November 13, 2014 2:58 PM
Found the parts I needed. Be here Tuesday. The control board $92, and sail
switch $8 , with shipping came to $108.
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bdub
'76 Palm Beach/Central Texas
www.bdub.net
www.gmcmhphotos.com
www.gmcmotorhomemarketplace.com
www.gmcmhregistry.com
www.facebook.com/groups/classicgmcmotorhomes
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