Heater Question

[fourteener]

I own a 2007 2720. We had an issue that surprised us and I would like to know if anyone else has experienced this. We went dry-camping for a week and our battery was running low (now we know it needed water), but turned the heater on and went to sleep. At 2am I woke to the smell of smoke (burning dust and spider webs) shortly followed by the smoke & CO alarms. The furnace burner had ignited but there wasn't enough power to turn the blower. The heater is a Suburban Brand, Model # NT20SE.
Questions:
1) Has this happened to anyone else?, and
2) Shouldn't there be a safety feature that shuts the heater down when it overheats or the blower won't turn?
After fixing the battery issue the heater seems to work fine, I simply don't want to chance burning up my TM. Please let me know what you think!

[ZekenSpider]

There were a few answers posted to this same question that you posted yesterday under the Appliances/Heater Problems thread. Go back to that thread. If you can't find it, let me know.

Jerry

[fourteener]

ZekenSpider,
Could you please help me locate my previous post. I did a search, and the only one I can find is my second post. That is why I re-posted it, as I couldn't locate the Appliance Thread Link Immediately after I posted.
Thanks,
Fourteener

[ShrimpBurrito]

It's here:
http://www.trailmanorowners.com/foru...ad.php?t=10904

Dave

[fourteener]

ZekenSpider or ShrimpBurrito,
For some reason I keep getting an error that says I don't have access to that site, would one of you be able to cut and paste it to this thread, so that I can see it.
Thanks,
Fourteener

[Keith Wire]

Fourteener,

The reason you can't get to that thread is probably that your free access to the full site expires after a month. You need to be a Site Sponsor. It only costs $12 a year and it was the best and cheapest thing I ever did.

Here is a link to the "Becoming a member of the Forum".

Keith

P.S. Here is the text of ZekenSpider's message.

We have had a problem or two, but nothing like your experience. Glad your OK and that all the backup alarms worked.

We have a 2010 3326 with an NT-20SE furnace. We had to work on ours so I know quite a bit about the 2010 version. (the factory forgot to connect the air inlet and exhaust outlet pipes on ours so we had fumes and smarting eyes until I figured out the problem).

The control circuit in our NT-20SE has two safety shut-offs that will close the gas valve. The first is a "sail switch" in the combustion blower fan air stream. If this switch does not detect sufficient combustion air flow, it will not allow the gas valve to open (or will close it again if the air flow drops off). The second is an over temperature switch that will close the gas valve if the recirculating fan air internal temperature gets too high.

If either of these safety features activate, the control board locks out the gas valve until the thermostat is cycled off then on.

It sounds like all your safety features worked properly but that still scares the heck out of you when things go to the limits of safe operation.

I know of no way to protect against this problem. As they say, "do not run out of electrical power". May be a low voltage alarm on the battery system?

Hope this helps,

Jerry

[fourteener]

Well, you know how they say, "Better Late than Never", I'm finally posting my solution over 2-yrs later (I did find the solution in June '11). Also, this is the second time I've posted this, so hopefully the server doesn't lose my post this time.

First, after sending Ed Lytle of Trailmanor my questions, he had me contact Ronnie Ellison the Service Manager of Airxcel/Suburban Products. He stated that the furnace should not have started without 10.5 DC Volts, and recommended to have the heater checked by a service center representative, which can be found by visiting their website www.rvcomfort.com.

I then contacted Dick Vogel, of RV Mobile Service in Brighton Colorado. I would highly recommend Mr. Vogel to anyone in the Denver vicinity as he was great (I believe he shifts his business to Phoenix in the winter, so you may have to wait for him to migrate back North). He tested the heater sail switch, high temperature limit switch, and the trailers propane system for possible leaks. Both limit switches tested out (OK), and the propane system pressure tested with no leaks at 11.5". For inquiring minds he tested the heat limit switch by blocking the heater with a small sheet of plywood, and stated that it went into shutdown just as it has been designed. His theory is that the battery must have been very close to the limiting voltage as stated above and that it most likely hit its temp limit and was in the shutdown stage when my alarms (CO & smoke) started going off. He stated that the Suburban factory coats the burners with a light grease to keep them from rusting, and that this grease (which is usually removed with limited use) started burning off, and that is what actually set off the alarms. He thinks that this was simply perfect timing (or imperfect timing as I look at it), and that we probably couldn't make this happen even if we had a voltage meter hooked-up in an attempt to recreate the calamity of errors.

We've been using the heater ever since he checked it out, and so far, so good. It does give us some peace of mind that it has been checked out. Hopefully some of you forum readers will find this helpful.