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-   -   Greenbrier Friedrich GUB100NDCI (http://www.diychatroom.com/f17/greenbrier-friedrich-gub100ndci-83081/)

artbuc 10-04-2010 10:14 PM

Greenbrier Friedrich GUB100NDCI
 
I could not find a Serial Number. This is an old NG two burner furnace - 100,000BTU. Pilot light comes on but main burners do not. Does anyone know what type of pilot sensing device this unit has? It looks like a thermocouple. Is there a way to check it with a VOM? I didn't have my VOM with me so I couldn't check to see if the main burner was getting 24V but I will check that later this week. I don't want to buy a new pilot sensor unless I can prove it is the culprit.

I wonder if I can even get parts for this unit? Thanks for your help.

kenmac 10-04-2010 10:29 PM

Did you push down a knob on the gv to light the oilot ?? If so. make sure you turned the valve / knob to the on position.. I would have that furnace inspected b-4 use it it's that old

artbuc 10-05-2010 06:16 AM

Quote:

Originally Posted by kenmac (Post 511604)
Did you push down a knob on the gv to light the oilot ?? If so. make sure you turned the valve / knob to the on position.. I would have that furnace inspected b-4 use it it's that old

This is my nephew's furnace. I was there helping his daughter with her algebra homework. I didn't have any tools with me but my nephew asked me to take a look. The pilot comes on the way it should on a call for heat. This was the first time this season he called for heat. There is a black box which sits on top of the GV. I assume there is a control board in there.

Do you know how old this unit is? Can you answer my original questions about the pilot sensing device? Thanks.

PS Because this unit has electronic (vs standing) pilot, does that mean the pilot sensing probe is a flame sensor and not a thermocouple?

kenmac 10-05-2010 11:25 AM

Quote:

Originally Posted by artbuc (Post 511755)

PS Because this unit has electronic (vs standing) pilot, does that mean the pilot sensing probe is a flame sensor and not a thermocouple?



Yes..... since you don't know mod.# you may have to post a pic of the valve. Not sure what valve you have

artbuc 10-05-2010 02:08 PM

Quote:

Originally Posted by kenmac (Post 511854)
Yes..... since you don't know mod.# you may have to post a pic of the valve. Not sure what valve you have

Thanks. You mean model # of the GV or the control unit or both?

kenmac 10-05-2010 02:18 PM

Quote:

Originally Posted by artbuc (Post 511924)
Thanks. You mean model # of the GV or the control unit or both?



Unit or furnace. correction I see the furnace mod # May be able to tell by the valve # Make sure you have a good strong pilot.. Weak pilot & they won't sense flame.. Looking at that mod # this is an old furnace.. May cost more to repair than a new unit.. I would also have the heat exchanger checked for cracks

artbuc 10-05-2010 02:55 PM

Quote:

Originally Posted by kenmac (Post 511932)
Unit or furnace. correction I see the furnace mod # May be able to tell by the valve # Make sure you have a good strong pilot.. Weak pilot & they won't sense flame.. Looking at that mod # this is an old furnace.. May cost more to repair than a new unit.. I would also have the heat exchanger checked for cracks

Nephew bought the house last year and the heater was inspected and heat exchanger was specifically cited as being ok. I have read that 9/10 times you can fix flame sensor by cleaning with fine emery cloth or a scotchbrite pad. We may try this. The pilot looks fine although I do not know what it should look like. I have seen many different pilot lights over the years in various aplliances and they all look a little different. On my furnaces you can adjust the gas flow to the pilot. I assume you can do that with the Friedrich unit too. I really don't want to do too much for safety reasons but I can clean the flame sensor and make sure the main GV is working. Do you know how many microamps I should see from the flame sensor?

kenmac 10-05-2010 06:08 PM

Different manfacures used several methods of proving pilot b-4 opening the gv. Some used a bulb that looks somewhat like a t.couple. the pilot flame would heat the bulb. liquid in the bulb would expand & make the circuit & open gv.


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