Suburban Furnace Problem, Please Help

[Pallansch]

Having problems with my Suburban NT-30SP

Input 30,000

It will run fine for 12 hours or so then all of the sudden shut off and try to start up again. It will run the starting cycle a couple times and not light then nothing. If i turn the thermostat off for a couple hours it sometimes comes back on. Also, sometimes if i just leave the thermo on it sometimes start back up after 6ish hours. Regulator problem? PLEASE HELP Thanks! Would like to try to fix it myself before taking to the local RV shop.

[harvey lee]

Does this heater set any codes or does it not have a code to tell you the issue?

My Attwood heater needs 12volts to operate. If my battery gets to low, the furnace will run, stop, reignite and then drop out again as there is not a full 12volts to keep it running. If I get that low, I start the generator and charge the battery in the house for awhile.

If the temps have been very cold, you could be out of pressure in your lp tank and if it sets in the sunshine for awhile, the tank can build more pressure and it would run again.

Does the furnace has electronic ignition or a pilot? There could be issues with a sail switch, limit switch, lp pressure, 12volt current supply and or a regulator. I would guess you have a electronic issue with the heater and if it has a control board to tell you, then you can see how the lights turn on and off or how many times they flash to resolve this issue.

[Pallansch]

Its happens when its 0 out and went its 30 out. I read about the half full tanks and what not. I had 2 full 30lb tanks and it still did it

[harvey lee]

Could be a 12v curerent supply, sail switch, limit witch and on and on.

Most of these heaters have to have a minimum of 11.5 volts to operate.

Try this link or an online search to resolve your issues.

http://www.ehow.com/how_7729808_troubleshooting-rv-suburban-furnace.html

You may need to start at the top, like checkinbg voltage and going on from there unless this frunace sets a code and you can see how it blinks to get you to your issue.

It may show in your owners manuel where to look for the codes on the furnace, if there is a issue, it should be flashing lights. I know on my Attwood, if it blinks 3 times, then stops, then blinks three times again I more than likely have a 12v supply issue with not enough volts to keep it running. Should be numerous other codes to tell you what to look for.

[Pallansch]

No codes that i know of, I run a generator 100% of the time. I thought about getting a separate battery for the furnace. It has electronic ignition. Thanks for the help

[fishingstar]

You should read some of the posts about regulators and lp tanks freezing up. If you are using a 20# tank at the temps we have they freeze up and can not vaporize fast enough.

Dan

[harvey lee]

No codes that i know of, I run a generator 100% of the time. I thought about getting a separate battery for the furnace. It has electronic ignition. Thanks for the help

Could be an ignitor also.

If it has no codes showing, then I would look to your lp supply and if you have enough pressure to supply the heater.

Lets say it is 15 out and your heater is running fine, then at night it gets to -15, your heater could quit if the tank is low or due to the colder temps, the pressure drops and no heat. Then say 5 hours later, the air temps warm and the sun is out, more pressure in the tank and wella, the heater works as it has enough pressure.

Air temps and how much propane in the tank can also be a huge factor.

I have had issue with a new house running 20#ers.

Hooked up a 100#er and all my issues went away even at -18.

I believe most of the fish house heaters need a lp supply of 11WC, one needs a gauge to check that. It's the supply of gas to your furnace. I would guess you may have a low tank on colder temps and not enough pressure to feed the furnace so the system shuts the furnace down.

[B-man715]

It runs 12 hours straight without shutting off?? That sounds like a problem right there.

Is it blowing hot air the whole time?

[Pallansch]

I guess I need to word it different, It runs fine for 12 hours! The thermostat works fine, Everything works like it should for about 12 hours.

[harvey lee]

When it will not run as in correectly and heats, does the fan blower turn on when you go to start the furnace? Or, does it simply do nothing?

[Pallansch]

The blower comes on

[outkast7222]

Could be a bad or mis-adjusted sail switch. That would be the first thing I would check. With out that working the gas valve will not open.

[jeff127]

I have a suburban furnace also and the first winter I used it I had a very similar issue and the sensor that shuts it off automatically when it gets too hot was faulty(kicking lp supply off at a temp below what it was supposed to be). It was an easy fix and has run fine for the last 4 seasons.