Atwood Furnace 7916-11 won't light

[ghatfield]

This furnace is in a 2006 Bambi 19. A video of the furnace can be seen here:

https://www.youtube.com/watch?v=nVNdcM81QmE

Also a photo of the furnace label is attached.

We have owned this trailer for about 3 years and the furnace has been unreliable since we bought. It is controlled by a thermostat and when turned on by the thermostat to provide heat it will try three times to light. If it does not light after the third try, it turns off and must be reset with a switch on the front of the furnace. I have had it serviced, but like many intermittent problems, it always works perfectly when the service guy is working on it.

We recently used the Bambi on a 7 day trip with nighttime temps in the low 30s. After the first night, when the furnace would no longer light at 1am, I filled the propane tank. Before filling it was about 1/3 full (6 gallon tank). After filling the furnace worked perfectly for the next 6 nights. Often it would light on the first try! Given the temps we were in, it would come on about every 15 minutes during the coldest part of the night.

So what does this tell me? Is there something wrong with the regulator or some other aspect of the propane supply?

Also, does anyone know where I can get a replacement Nylatch (see pics) that locks the bottom of the front grill? The one I have is broken.

Thanks in advance.

[ghatfield]

Available from Amazon.... of course! See attached.

[HowieE]

When you filled the tank were you relying on a gauge or weight to tell you it was 1/3 full. Weight is accurate.

If by gauge it sounds like the tank was empty.

There is a problem with heaters that is effected by the way the tanks are filled. You have to leave one tank on the system and have pressure on the system while filling the other tank. If the pressure is lost the line will have air in it and the orifice in the heater is too small to purge the air and it will go off on proof of flame.

If this happens loosen the gas line at the heater till you smell gas and tighten down and retry to light.

[ghatfield]

I actually weighed both tanks and subtracted the tare weight. Yesterday I refilled the tank that we used for 6 days, of which 3 nights were below freezing. Total used, 2.8 gallons.

The problem is probably not air in the line since most of the time it will light, but not on the first try (furnace tries 3 times). After filling the tanks, the furnace lit on the first try most of the time. Before filling, it was normally on the second or third try and with some failures.

I think I will replace the propane regulator and see if that has an effect. We have another trip planned for northern AZ later this month. That will be a test of the furnace for sure. I think I will try this regulator:

https://www.amazon.com/Cavagna-890-0...pane+regulator

It has been mentioned as a replacement for the original equipment regulator.

George

[MissingLink5]

When I was at Alumapalooza this summer the service dept came to my trailer and checked the oven propane pressure, because I was having similar problems but with the oven lighting after several tries. There is a regulator (on mine, near the propane tanks) that can be adjusted up or down depending on the pressure coming from the tanks. As I recall, my pressure before adjusting was around 11. The service manager adjusted it up to about 12 and it has worked fine ever since. They tested the pressure with a pressure gauge connected to the propane line coming into the oven. They tilted up the top of the range (lifts up from the front) and hooked the gauge on a gas connection located there. It requires two people to adjust, one to watch the pressure gauge and the other to turn the screw on the regulator up or down. They turned the pressure up as far as they could and indicated if I continue having problems I would have to get a new regulator because the pressure was still lower than it should have been.
I maybe wrong on the pressure numbers (11 and 12) but the owners manual should tell the correct settings.

[Chaplain Kent]

You did not say if you were off the grid or on a campsite with electricity.If you do have electricity I suggest a small electric heater. We use one exclusively here in the upper Midwest and rarely use the furnace for our 30 footer. When it really gets cold we supplement the space heater with the heat strip in the AC.

[ghatfield]

Thanks for the suggestions.

We were on 110v 30amp for all of the nights. We rarely boondock... almost always in an RV park. We do have an electric heater as a backup, but it is only about 5,000 btu (1500 watts) while the gas furnace is 15,000 btu plus. On a cold night the furnace will come on for about 10 min 3 to 4 times per hour. That makes me think that the electric heater would not be adequate. It would be nice not to use the furnace.... it is pretty noisy.

As for the heat strip in the AC, it is not controlled by the thermostat which means the fan is on 100% of the time. It is also noisy.

I will change out the regulator and report back.

George

[ghatfield]

After viewing several Youtube videos on RV propane regulators, I decided to change mine to see if that will improve the furnace performance (i.e., always light on the first try). These regulators have rubber parts that can become stiff over time and reduce the effectiveness of the regulator. These are the parts I bought from Amazon:

Regulator: The model 253 is an upgrade to the 250 that came on my trailer.

https://www.amazon.com/Exceisior-MEG.../dp/B00KPR9Q30

There are a couple of irritating differences. First the green/red window now only faces to the front which makes it impossible to see with the tank cover in place. I used a little mirror which helps (see pic). Second, the new one has bolt on the side of the secondary regulator which can hit the tank if care in not taken in installing the regulator. No big deal, but I didn't want it wearing on the tank over time.

Pigtail hoses: Mine were pretty stiff so I replaced them with 12" pigtails. These are about an inch too long, but worked out OK.

https://www.amazon.com/Camco-59053-P.../dp/B0014E3MSS

Teflon Tape: This yellow tape was recommended for the main line coming out of the regulator. The other fittings do not require tape.

https://www.amazon.com/Oatey-31403-Y.../dp/B000L8BHD0

Everything seems to work fine, but the tanks are full and the furnace works fine when they are. It will probably be next summer before I know if this repair made a difference.

I was able to get a Nylatch through Amazon, but the one that came is about 1/16" shorter than the original. It works, but I have to push the front of the grill in just a bit. Also, these latches require assembly. Not complicated, but a pain to get the two pieces together.

George

[ghatfield]

As mentioned above, I was able to get a new Nylatch from Amazon for the furnace cover. But it would not secure the cover without bending it in. The Nylatch seemed to be too short. But on further investigation, the problem was with the Nylatch receiver (i.e., the "female" half of the latch). The receiver is on the bottom of a circuit board for the furnace. The board is only secured with two screws and this does not secure the receiver.... so it is pushed in when one tries to insert the "male" part of the Nylatch. So I fashioned a spacer which holds the bottom of the board in place. It is secured with 3M double stick (gray) tape. That did the trick.

[ghatfield]

Just got back from a two-day trip to Payson, AZ. Nighttime lows were in the 40s and the furnace came on about twice an hour for 15 minutes. With the new regulator it lit on the first try every time I heard it. And it seemed to light faster. Although I won't know for sure until the propane tank gets lower, the replacement of the regular seems to have solved my problem.

[ghatfield]

Replacing the regulator seems to have solved my furnace problems. We just spent another 3 nights with temps in the 30-40 F range. The furnace worked perfectly.

George