Propane system mystery

[Keystone]

I hope there is someone out there who can diagnose my latest B190 failure. On my last winter camping trip, the furnace quit working, after cycling properly for a few hours, even though the monitor panel indicated lots of propane remaining. Battery voltage was fine. The fan gleefully screeched along, but burner would not light, though it tried. Also, the stove did not work. It was cold (0 deg +or-) outside) but we've used the furnace in even colder temps. Yes, the gas valve was completely open.

Now that it's finally warmer (40 deg), and I'm not camping, I investigated further. The monitor panel still shows lots of propane, and, of course, now the furnace and stove are working perfectly. In the driveway.

What might have gone wrong? How can I avoid this problem next time? I'm fast losing my camping credibility--seems to happen when it's freezing out and the heat quits... These intermittent problems are hard for me. Does the regulator need to be replaced? Or, could I have just tried something like tapping on it or closing-re opening the valve? Did some intake thing freeze up? Also, if I need repair, what kind of trade can fix this problem? Neither my mechanic nor the Propane company in town want to touch it. It's 65 miles to Camping World, and not in a good direction. Please help!

[skater]

My guess is something went awry with the regulator; they do wear out over time. In particular, one of the jobs of a regulator is to cut the flow if there's a major leak, so my guess is something went wrong with that functionality. To replace it, you have to burn off all of the propane, then open the system and replace the regulator, followed by checking the connections for leaks. For obvious explosive reasons, this is best done by a shop.

[Kentuckian]

Keystone,
I don't have a suggestion on the propane issue. But as for the screeching, the fan motor bearing seems to burn off its oil due to the nearby heat. A few drops of oil to the bearings at each end of the motor housing cured the screeching in my unit.

[kitemanks]

I'm a recent owner of a 1994 B190 however after buying the RV I noticed the radio didn't work, and the speakers were rotted. I did some door ketch repair as well, and replaced the aged 3rd brake light whose lens was just sitting in the housing. My point being things wear out. Now even on you house furnace the gas line is left open by a thermocouple that is in the fire chamber and as long as that senses heat the flow of gas is allowed to continue, when the thermocouple doesn't sense heat the flow of gas is shut off as a safety precaution. I would guess there is a similar set up on the LP fixtures on these RVs with the small size. I would go for the $5.00 answer open that bad boy up locate this thermocouple, and if there take a wire brush to it and get the corrosion off as best you can.
That might fix the problem totally, but it would be nice to know it worked in super cold conditions before your in them again. The condition you find that thermocouple in might give you an indication of that.

[Keystone]

Thanks, all of you, for the helpful posts on this propane issue. I'm headed out on a multi-day trip this afternoon and have not taken any action to solve my problem, except to verify that the propane system (furnace and stove, anyway) still works in the driveway. I hope to burn through all the remaining propane on this trip, and then make an appointment for repairs.

I'll definitely ask for the screech-mitigating fan lubricant, the thermocouple scraping, and a new regulator. However, I'm getting a lot of pressure on the home-front to spring for a new furnace instead of a repair, but I think (or hope) the old one just needs rehabbing. If anyone has replaced their furnace and experienced a life-changing event with it, please post on that.

Anyway, I'll post again after the trip to the RV shop to report in.

[Keystone]

Hi Kentuckian,
Would you kindly post a photo of the furnace lubrication locations that solved the screech? And maybe a little tutorial about how to get at them? I finally pulled off the furnace supply vent cover, but it was not obvious to me what to do next.

Thanks,
Keystone

[Kentuckian]

Hi Keystone,
I can't produce that tutorial for you without removing my furnace and disassembling it. If I have to get in there again, I'll be glad to do so at that time. But, for now let me give you a rough step by step from memory.

1. Turn off your propane tank.
2. Turn off the breaker to kill power to the furnace.
3. From inside the B190, remove the faceplate of the furnace and the screws that secure the furnace to the closet wall.
4. Remove the closet floor so you can get at the wiring.
5. Disconnect the wires to the furnace (under wires nuts near the furnace).
6. Disconnect the gas line.
7. Disconnect the air duct that runs from the furnace towards the front of the B.
8. Slide the furnace out onto the floor of the B.
9. Remove the round blower cover towards the back right side of the furnace.
10. Remove the motor/blower assembly from the furnace.
11. On my motor there was a metal oil pipe coming from the front bearing of the motor. I added a few drops of non-detergent 30 weight oil into this tube. I also placed oil around the bearing at the rear of the motor. Spin the motor by hand to help work the oil into the bearings. I let the assembly sit overnight and added more oil the next day. My motor quit making the screeching noise after letting it sit overnight. I added a few more drops, spun the motor to work the oil in then reassembled the furnace.
12. Reassemble following the reverse of these instructions and test.

The dis-assembly is a pain but fairly obvious how everything comes apart and goes back together.

As I remember you need to take care with two specific re-assembly steps. a. Sliding the furnace back into the wall. Make sure to line up the furnace exhaust port with the exhaust port mounted to the wall of the B190. This can be tricky. You don't want to exhaust into the cabin of the B190! b. Be careful when reconnecting the propane line to not twist the valve assembly and to make sure to have a secure seal on the gas line.

Hope the above helps.

Regards, Kentuckian

[Keystone]

Wow! Awesome tutorial! Thanks for taking the time to describe the procedure in such detail. Knowing that this worked for your furnace, I'll give it a try.

[Keystone]

I decided to replace my entire furnace rather than try to rehab the blower motor. It was about $500, plus another $50 for the right vent kit (the kit included in the furnace was too short). Kentuckian's tutorial was really helpful in working through the steps of pulling out the old one. Finally finished it this week. See my gallery for photo documentation: http://b190.com/gallery2.php?g2_itemId=2805. Atwood claims there have been improvements in the operation and control strategy over the past 20 years in this furnace, and I hope that's true, but it sure looks similar to the one I replaced.

And, I finally had the regulator replaced. I watched the technician at the propane supply shop perform the installation, and it looks like a straightforward job--for someone who has done it 100's of times . Very glad I had the expert do it, and he adjusted it for altitude, and leak-checked every propane fitting in the entire van (including my new furnace installation). All that, and a half tank of propane, for just $35! Wish I had done it sooner. By the way, replacing the regulator does not require emptying the tank--just close the valve.

It is awfully nice to have not only a quiet fan motor, but also a trusty new heater unit and an up-to-date regulator for the upcoming winter camping season. Thanks again everyone for all the help.

[Kentuckian]

Hey Keystone! Great news that you finished installing the new furnace! An wow! $35 is pretty reasonable for the propane and regulator service that you had done. It looks like your ready to take on winter now!

[Keystone]

Hi all. Here's an update on my propane system's cold weather operation. I've continued to have problems in near- and sub-zero temps with propane not flowing. Maddening! I finally found a propane technician who diagnosed the problem: water in my propane tank. He added methanol to the tank by first purging his fill line and then pouring in about 2-3 cups of methanol while carefully holding the line upright to avoid spilling. Keeping an angle on his fill hose he attached the fitting to my tank. Then he turned on the propane and the pressure forced in the methanol along with enough propane for an 80% fill.
I am just back from an extended ski trip to Idaho and Utah in really cold temps and the system has not hiccuped even once. I've included a pic of the filling procedure for anyone who might have the same problem. I'd suggest going to a real propane dealer and not a hardware store for this. The tank does not have to be empty to add methanol.
Rereading the old original b190 manual, I see that moisture in the tank was even mentioned as a possibility, but now we know what to do about it. Happy winter travels!


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