Propane line problem?

2018 Winnebago View 24J with a full tank of propane. This is sort of a weird problem. Actually, several problems all at once. Looking for a few pearls of wisdom.

We turned on the furnace a couple of days ago and it has apparently died. Air is blowing hard and it actually ignites but goes out in less than a minute. It will repeat this several times and then it won't even try again until we turn it off and then back on. If I restrict the air flow a little from the outside exhaust it will stay lit and heat my hands (a little) for as long as I hold my hands in the way of the exhaust but it's not enough to heat the air going to the floor vents. Seems like it's really weak when it lights off. So, thinking that maybe we have a propane flow problem I cycled the outside and inside propane cut-out switches and no change in symptoms. I then tested the fridge and it will not run on propane either. Hmmm... I then tested the cook top and the hot water heater and they are strong as ever. Is there anything in common with the lines going to the fridge and furnace? Also, I never could get the thermostat to behave. Sometimes it gives me the option of gas or electric heat and other times it forces me to select gas/elec together. I am aware of how the gas will supplement the heat pump if there is too much of a difference between desired temp and actual. But it didn't seem to matter if I had the thermostat one or ten degrees above the interior temp. Really random.

On a completely unrelated note, we turned on the heat pump and it won't heat either. Are you kidding? These are all brand new problems. I found some pretty well done videos on it so I need to troubleshoot it. The three year warranty was up in July. Thankfully we were plugged in and have always used a small electric space heater but man it was super cold out so I was just trying to knock the initial chill off. We fired up the chassis and oh boy, that Mercedes heater will run you out of the camper.

Thanks in advance!
 

outbound

06/2500/140
are any of the furnace output vents blocked? (carpet, misc clutter etc)
these things are 'try 3 ignition' and will lock out if no go after 3x
and have you run out the tank/empty lately?
the refrig sounds like an air bubble in the line - try crack the nut and bleed until you can smell propane.
oh... and 'heat pumps' - like a rooftop RV a/c unit will only heat in warmer than 40degF air temps,
UNLESS they have an electric element... so if it's colder than 40 or so and no electric element = NO HEAT
 
Thanks Outbound. All vents are clear. We have never run the tank empty at any point since we've owned the rig. Maybe I'll bleed the lines on both the furnace and fridge and see what happens.

I never knew that about a heat pump. What the hell good is a heater if it won't work when the weather gets down to a temperature that you actually need it? I'll try it today once it warms up. It supposed to be around 44 here in Virginia Beach today.
 

TJLee089

2013 Itasca Reyo 25R
It's not that a heat pump suddenly stops producing heat at a specific temp. It simply produces less heat as the temp decreases. My heat pump works fine at 40F. RVs are not well insulated as compared to a house. Thus, heat pump capability in an RV would be expected to be less. If your furnace kicks on while the heat pump is running, that means the heat pump has not yet, or cannot, reach the temp you have selected. Assuming all the equipment is working properly, it's simple enough to see what the capabilities of your heat pump are in lower temps.
 
Heat pump tested out great today in 50 degree weather. Fridge is working fine as well although I did nothing to it. The furnace will stay lit but simply will not warm the air in the vents. Blows hot air out of the exterior pipes but cool air on the inside. It seems as though the furnace is simply not getting hot enough to warm the air. How can the furnace be lit but not warming the air? There are no obstructions.
 

OrioN

2008 2500 170" EXT
Heat pump tested out great today in 50 degree weather. Fridge is working fine as well although I did nothing to it. The furnace will stay lit but simply will not warm the air in the vents. Blows hot air out of the exterior pipes but cool air on the inside. It seems as though the furnace is simply not getting hot enough to warm the air. How can the furnace be lit but not warming the air? There are no obstructions.
Have you recently filled the tanks, and at a station that you don't normally use? There are places or cases where 'inferior' or low quality is sold.

Secondly, the regulator may be toast, or malfunctioning from getting contaminated with the 'skunk oil' used in propane which got into the regulator from overfilling.
 
I second OrioN. Like your diesel, get your propane from a source with constant turnover. If you get some with oil in it it will foul the regulator.
The last few years WBGO has been installing Camco and Fairfield regulators. They are not reliable, have a limited life and WBGO knows it. Order a Marshal Excellsior Regulator. I'm not sure which model for your year View. There has been a lot written about regulators on other V-N Forums. If you do a search here, discussion@view-naviontech.groups.io you should find more comments reguarding Lp regulators.
 

Alphacarina

2006 Itasca Navion 23H
I never knew that about a heat pump. What the hell good is a heater if it won't work when the weather gets down to a temperature that you actually need it?
All air to air heat pumps suffer from the same problem - They can't pump any heat when there's none out there to pump. My home system is also set to switch over at 40 degrees to propane and it switches back once the ambient warms to 40 again. The 'solution' is a closed loop system which uses the earth's stable temperature (roughly 60 degrees, summer and winter) instead of ambient air as the source for the pump . . . . but of course, that's not practical in an RV :p:

Don
 

TJLee089

2013 Itasca Reyo 25R
It can be tricky to determine if the LP flow is restricted. The stove and water heater may appear to work fine even though they are not at full capacity. Even the fridge may be fine in moderate, i.e. low outside temps. The furnace air outlet should definitely be hot. It could be a regulator issue as mentioned above or possibly some dirt/restriction at the furnace LP nozzle. One of the first things I would do is check the LP line pressure with one of the appliances (stove) running. It should be 11" wg. See post #28 here for how-to-do options. If LP pressure is OK, I would look to the furnace LP nozzle.
 

hoosierrun

Active member
The furnace will stay lit but simply will not warm the air in the vents. Blows hot air out of the exterior pipes but cool air on the inside. It seems as though the furnace is simply not getting hot enough to warm the air. How can the furnace be lit but not warming the air? There are no obstructions.
This almost suggests that something is wrong with the blower. Even though it is running, perhaps some blades came detached from the outer ring leaving what amounts to a spinning wheel. If the high limit sensor gets too hot from lack of air flow over it, it will shut the unit down. Hot air coming out the exhaust vents but not coming out the duct vents suggests a bad blower, an obstruction, disconnected ductwork right at the unit, or a bad control unit that is not allowing the blower to come to speed. Also, I have heard of a blower wheel that cracked at the motor shaft and just free wheeled... never getting up to speed. Here is a picture showing the blower and you can see that it is all plastic. There is a small fan on the rear of the motor that exhausts the gasses and a larger bladed fan that is the forced air fan for heat. Those have been known to fail and are a PITA to repair. Suburban designed these so that if the cheap fan blade fails, you can almost spend the cost of a replacement furnace to fix unless you can DIY. Long gone are the metal fan blades and the squirrel cage fans that never failed. We all know that heat and plastic have a limited lifetime. I really hope it's not your problem, but from the description, it sure sounds like it. On the other hand, a totally failed fan that pushes no air will not allow ignition because the sail switch won't get pushed closed, so this really needs to be diagnosed to see if the fan is partially failing.
 

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sprintah

VS 30 - 2020 Unity TB
You might also consider that if your propane tank is low, and it is cold outside, it is common that the propane will condense and pool at the bottom of the tank and not release enough propane vapor to reliably fire the furnace. If the behavior of the furnace changes when the outside temperature goes up, then that is a solid clue. Topping off the propane tank usually fixes that problem.
 

TJLee089

2013 Itasca Reyo 25R
Not true. Assuming there is ANY liquid LP in the tank, pressure is affected by only one variable: temperature. It is possible that if the LP is very cold, the flow (i.e. the rate at which the liquid vaporizes) will be insufficient to support the demand. In any case, topping of the LP will do nothing. The vapor pressure in the tank is unaffected by the liquid level.

You might also consider that if your propane tank is low, and it is cold outside, it is common that the propane will condense and pool at the bottom of the tank and not release enough propane vapor to reliably fire the furnace. If the behavior of the furnace changes when the outside temperature goes up, then that is a solid clue. Topping off the propane tank usually fixes that problem.
 

rollerbearing

Well-known member
Actually liquid level does influence vapor pressure at high flow rates. If the liquid level is low, the heat of vaporization can lower the temperature of the small liquid mass enough that the vapor pressure drops significantly. If enough appliances are running for a long enough time (on a very low tank) it could be a problem. High flow systems will typically parallel large tanks (kept full) and add tank heaters to avoid this.

Small blanket heating pads are sold for BBQ tanks to prevent this during cold weather grilling. Their literature mentions the ability to use more of the tank before requiring a refill as a selling point.
 
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TJLee089

2013 Itasca Reyo 25R
You are correct, thus LP tanks show condensation and/or frost on the outside at high flow rates. However, the OP's suggestion that "propane will condense and pool at the bottom of the tank" is misleading. As you suggested, the energy required to vaporize liquid to gas comes from the bulk liquid which cools. If the heat transfer from the outside air to the liquid is sufficient all will be well. If the demand is high, outside temp is low, and the mass of liquid is small, the liquid can become significantly colder than the outside air, thus lower vapor pressure unable to support high demand uses such as the generator or furnace. Not common but possible. Thanks for the comment.

Actually liquid level does influence vapor pressure at high flow rates. If the liquid level is low, the heat of vaporization can lower the temperature of the small liquid mass enough that the vapor pressure drops significantly. If enough appliances are running for a long enough time (on a very low tank) it could be a problem. High flow systems will typically parallel large tanks (kept full) and add tank heaters to avoid this.

Small blanket heating pads are sold for BBQ tanks to prevent this during cold weather grilling. Their literature mentions the ability to use more of the tank before requiring a refill as a selling point.
 

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