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CampingInADK · 05-01-2016, 03:19 PM

This is actually the beginning of the 3rd camping season. flushed everything out to get ready for our first trip this year and when I ran the furnace something just didn't seem just right. BUT....... we went anyway and after about the 3rd or 4th light off it wouldn't light off. I would turn the t-stat to off then back on and it would then sometimes light off.
I accessed the furnace area and removed the front cover to see what the flame looked like and had my wife turn the t-stat to on. What I saw was a "lazy flame" not a strong crisp flame that I remember.
I might make mention that I have a Suburban model NT-30SP.
Also, the reason I think that something was wrong was because it didn't seem like the blower was as strong as before.
Could it be the blower or the gas valve or both ?
Thanks in advance

palehorse89 · 05-01-2016, 03:26 PM

Are your battery(s) up to full charge? And in good condition?

CampingInADK · 05-01-2016, 04:47 PM

Yes. freshly charged but am plugged into 30 amp ac circuit. Do you think that a bad battery would make this happen even though I'm running on ac ?

Parrott_head · 05-01-2016, 05:55 PM

The lazy flame may be a symptom of restricted gas.
If your other gas appliances are working well, with proper flame height, I would check to see if there is a screen in the inlet of the gas valve that has gotten plugged off a bit.

If so do not try to operate with the screen removed or damaged. It keeps crud from getting into the internals of the gas valve and causing a valve to stick open.

If you are not familiar with this sort of operation have a service tech handle it. AC's that don't function correctly are an inconvenience, furnaces that cannot shut off are deadly.

If you Google Furnace Service Manual, Suburban NT-30 there are some excellent online resources.

Just us good judgement and caution. Saving a service call won't seem like such a good deal if you burn yourself or your equipment.

coldfusion · 05-01-2016, 06:22 PM

Dirty flame sensor? Try some fine sandpaper on it to take off the crud

IC2 · 05-02-2016, 05:24 AM

Mud daubers and some spiders like to nest in furnace, HW heater and fridge burner tubes - they seem to 'enjoy' the odor. It may be a simple disassembly, clean and restore. If not, then you need to dig deeper. What you see may only be a pilot flame based on your description. A new thermocouple then MAY fix the problem - and most replacements can be purchased at any big box store for ten bucks or less.

CampingInADK · 05-08-2016, 03:49 AM

Thanks to all that responded ! Finally was able to get back up there to do some more troubleshooting and had to remove the furnace and bring it home so I could go right through it. I checked all the safety switches and then the gas valve coils. That's where the problem is. One coil has 49 ohms and the other is open (0 ohms). I am ordering a new gas valve today.
Again, thanks for all your responses.

palehorse89 · 05-08-2016, 07:46 AM

Glad to read you have found your problem! Thanks for the update......

TheMatrix · 05-08-2016, 10:38 AM

Quote:

Originally Posted by CampingInADK

Thanks to all that responded ! Finally was able to get back up there to do some more troubleshooting and had to remove the furnace and bring it home so I could go right through it. I checked all the safety switches and then the gas valve coils. That's where the problem is. One coil has 49 ohms and the other is open (0 ohms). I am ordering a new gas valve today.
Again, thanks for all your responses.

You rock! Well done!. I would have taken a sledgehammer to it lol.