Propane Heater stopped working 2013 BH 3685

[gslabbert5119]

Ok so my furnace started working intermittently over the 3 weeks that I was out of country, and the wife about froze. (Unhappy wife is not a good thing.

Anyway ?I have been through the debugging plan and have searched threads for intermittent issues.

What have I found ...
1. The aircon works just fine and the fan comes on for the aircon on both units
2. The propane tanks are full
3. The hot water heater propane heating works fine
4. Plenty of gas to the range.
5. The furnace clicks 3 times when attempting to start but does not fire up.
6. The pipes appear clean (I removed the cover and looked into them with a flashlight)
7. I flipped the switch off that is at the propane unit, left it off for 5 minutes, turned it back on and the unit clicked once every 30 seconds in am attempt to fire up once I turned the thermostat inside the rig.
8. I checked the 12v 20 amp fuse and it is fine. I did clean it just in case
9. My batteries are currently at 11.85v, but being on shore power this should not be an issue (need to insulate them as the are loosing about 1 v at night when it gets cold, but that is a different issue)
10. flipped the lever on the propane regulator to the 2nd tank to check if it was not a propane tank issue (nothing changed)

So I am fresh out of ideas, as the regular seems to work fine as the hot water heater and the gas range have no issues heating or starting.

Oh, how do I test the heat pump to make sure the pump has not died ?

Thoughts ideas and suggestions are most welcome.

 

[cookie]

Re: Propane Heater stoPeacepped working 2013 BH 3685

If you are plugged into shore power your batteries should be fine no matter what the temp is and if your batteries are at 11.85 then your converter is not charging.
And I am not sure that your furnace will run at that low voltage.
Since you recently replaced your converter I suggest that you revisit it and find out why it is not charging while on shore power.

Peace
Dave

 

[gslabbert5119]

Re: Propane Heater stoPeacepped working 2013 BH 3685

If you are plugged into shore power your batteries should be fine no matter what the temp is and if your batteries are at 11.85 then your converter is not charging.
And I am not sure that your furnace will run at that low voltage.
Since you recently replaced your converter I suggest that you revisit it and find out why it is not charging while on shore power.

Peace
Dave

Dave the batteries are charging (float charge right now), I have solar system and an inverter. No sun no charge and the cold drains them.
I will check during the day as we have no clouds and will see if the unit starts a little later.

I suspect that the blower board needs replacement

 

[HOOKERUP]

Check to see if ignition is lighting pilot. There is a sensor that needs heat to make main burner light. If it fails to ignite it will go into lockout.

 

[gslabbert5119]

Check to see if ignition is lighting pilot. There is a sensor that needs heat to make main burner light. If it fails to ignite it will go into lockout.

Thanks for the info.

Where do I find that pilot light, I assume that it is a different pilot light to the hot water heater?

AND ...
once I find where that pilot light is and find that it is not burning, what is the solution .

I say this for I see no obvious pilot light anywhere near the furnace blower

TIA

 

[danemayer]

When the thermostat calls for heat, the furnace blower starts. After about 25 seconds, the gas valve on the furnace should open and the control board should fire the igniter. Assuming there is a spark, and there is propane flow, there should then be flame. The igniter has a flame sensor that if no flame is detected, signals the control board to close the gas valve. The control board attempt ignition 3 times and then lock out. The thermostat must be recycled out of heat/furnace mode to clear the lockout.

Although you didn't mention the blower starting and running, it must be ok or there wouldn't have been any ignition attempts. If the ignition attempt doesn't produce a flame, then either the spark is weak or there's insufficient propane flow. While the water heater and stove operation are good indicators of propane flow, they're not conclusive. The furnace needs a much higher rate of propane flow to operate correctly. A common problem is opening the propane tank valves too quickly, triggering the overflow protection device. There may be enough propane flowing to operate the water heater and stove, but not the furnace. You might also inspect the propane lines between regulator and furnace. If using a lot of propane, additives can pool in the hoses causing partial blockage.

If you're at high altitude, you can also have problems with ignition.

Low voltage on the 12V DC side may cause a weak spark. If you're on shore power, and the control panel doesn't show 4 lights, you have a problem that needs to be corrected. If you're boon docking with solar and your batteries are down to less than 12V, that could be the problem. I think in otherwise ideal conditions, a furnace may operate at lower voltage, but when is everything ideal?

At low voltage, the blower may have a problem getting above 75% of normal speed to keep the sail switch closed. If just barely enough power to close the switch, when the ignition sparks, the voltage required for the ignition circuit could cause the blower to slow and open the sail switch, cutting the propane flow.

Make sure you don't have anything restricting furnace airflow - like registers that are partially covered, or a blocked air return. If the blower isn't able to run at full speed because of a restriction, it could be slowing as ignition is attempted, causing a gas valve shutdown.

It could also be a combination of these things.

Or it could be poor wire connections at the furnace. Or a marginal control board.

- - - Updated - - -

Thanks for the info.

Where do I find that pilot light, I assume that it is a different pilot light to the hot water heater?

AND ...
once I find where that pilot light is and find that it is not burning, what is the solution .

I say this for I see no obvious pilot light anywhere near the furnace blower

TIA

You almost certainly have Direct Spark Ignition (DSI), not a pilot light.

 

[gslabbert5119]

When the thermostat calls for heat, the furnace blower starts. After about 25 seconds, the gas valve on the furnace should open and the control board should fire the igniter. Assuming there is a spark, and there is propane flow, there should then be flame. The igniter has a flame sensor that if no flame is detected, signals the control board to close the gas valve. The control board attempt ignition 3 times and then lock out. The thermostat must be recycled out of heat/furnace mode to clear the lockout.

Although you didn't mention the blower starting and running, it must be ok or there wouldn't have been any ignition attempts. If the ignition attempt doesn't produce a flame, then either the spark is weak or there's insufficient propane flow. While the water heater and stove operation are good indicators of propane flow, they're not conclusive. The furnace needs a much higher rate of propane flow to operate correctly. A common problem is opening the propane tank valves too quickly, triggering the overflow protection device. There may be enough propane flowing to operate the water heater and stove, but not the furnace. You might also inspect the propane lines between regulator and furnace. If using a lot of propane, additives can pool in the hoses causing partial blockage.

If you're at high altitude, you can also have problems with ignition.

Low voltage on the 12V DC side may cause a weak spark. If you're on shore power, and the control panel doesn't show 4 lights, you have a problem that needs to be corrected. If you're boon docking with solar and your batteries are down to less than 12V, that could be the problem. I think in otherwise ideal conditions, a furnace may operate at lower voltage, but when is everything ideal?

At low voltage, the blower may have a problem getting above 75% of normal speed to keep the sail switch closed. If just barely enough power to close the switch, when the ignition sparks, the voltage required for the ignition circuit could cause the blower to slow and open the sail switch, cutting the propane flow.

Make sure you don't have anything restricting furnace airflow - like registers that are partially covered, or a blocked air return. If the blower isn't able to run at full speed because of a restriction, it could be slowing as ignition is attempted, causing a gas valve shutdown.

It could also be a combination of these things.

Or it could be poor wire connections at the furnace. Or a marginal control board.

- - - Updated - - -



You almost certainly have Direct Spark Ignition (DSI), not a pilot light.

Thanks Dana,

Ok so the blower motor is NOT running at any point, though I can hear a click every 30 seconds, but 3 clicks only

I am in the Dallas area so altitude is not an issue.

Battery voltage at this point is 12.34v, and I have 61v being sent by my solar system, so battery power is good.

At this point I am hoping that it is the control board that is above the blower.

Anyone have a part number for the board per chance ?

Oh, I closed the regulator valves and then opened them extremely slowly, so that I did not hinder any propane flow.

Everything worked just fine last light when we went to bed, and this morning nothing fires up.

Dana any other ideas ...

Thanks
Gavin

 

[danemayer]

If the blower motor NEVER starts, the most likely cause is a wiring problem. The thermostat signals a relay located with the air conditioner that sends 12V DC to the control board. If you have 12V at the control board, but the blower doesn't run, it's probably the board.

If you don't have 12V DC at the control board, it's probably a bad connection at the wire nuts where the trailer wires connect to the furnace wires.

The parts list shows the board for the SF-42 furnace is pn 520820. Here's a link on Amazon. Suburban 521099 may also work. I think 521099 is a newer design that also works in Suburban water heaters, but has a bit different mounting scheme.

I've attached the parts list.

 

[gslabbert5119]

Thanks Dana, I have ordered a replacement board.

 

[gslabbert5119]

Ok, so I received the new Dinosaur board for the 12v propane furnace, and installed it which was amazingly easy (OMG something easy on an RV lol )

Anyway the blower kicked in so I am guessing that something went bad on the original board.

Sadly that was not the end of the issues as I still had no heat, and being really deaf I did not notice a funny sound coming from the blower. Well I eventually heard it, and had to take the entire system out of the case and out of the RV, only then did I find the issue.

The 2 screws that hold the sailswitch in place had come loose and the the sailswitch had flopped around hitting the plastic blower wheel, which was partially destroyed, and the sailswitch was bent and non functional.

So I have just ordered a metal blower wheel and a new sailswitch, hopefully that will resolve the issue.

I will keep everyone posted.

 

[Oregon_Camper]

Ok, so I received the new Dinosaur board for the 12v propane furnace, and installed it which was amazingly easy (OMG something easy on an RV lol )

Anyway the blower kicked in so I am guessing that something went bad on the original board.

Sadly that was not the end of the issues as I still had no heat, and being really deaf I did not notice a funny sound coming from the blower. Well I eventually heard it, and had to take the entire system out of the case and out of the RV, only then did I find the issue.

The 2 screws that hold the sailswitch in place had come loose and the the sailswitch had flopped around hitting the plastic blower wheel, which was partially destroyed, and the sailswitch was bent and non functional.

So I have just ordered a metal blower wheel and a new sailswitch, hopefully that will resolve the issue.

I will keep everyone posted.

Pictures???

Sent from my SM-N950U using Tapatalk

 

[gslabbert5119]

Pictures of what parts - or Damage ?

I will photograph the wheel when I remove it.

Here is the damaged sailswitch

Here is the link to the replacement blower wheel. I am replacing the fragile plastic one with this metal unit

https://www.amazon.com/Suburban-350...words=Suburban+350129+Furnace+Room+Air+Blower

 

[Oregon_Camper]

Pictures of what parts - or Damage ?

Yea, I was hoping for images showing the problem/damage.

 

[gslabbert5119]

Well it is Sunday morning and the weather has finally allowed me to work outside and repair the furnace. I have to replace the furance blower wheel and the sailswitch. To do that I had to remove the entire furnace as and then take the darned thing apart.

So it is working now and I had to replace 3 items.
1. The Blower board, which I covered earlier
2. A new Sail Switch that was the cause of all the issues
3. The plastic blower wheel

Once I figured out how to do this the entire repair took about 30 minutes from start to finish.

What happened to break the system

It appears that the screws holding the sail switch to the inside of the blower wheel casing fell out and the arm of the sail switch broke of the entire lower portion of the blower wheel (see pictures). These pieces then jammed the motor, or put sufficient resistance on the rotation that the board overheated or shorted out somehow.

With all 3 parts replaced, the furnace immediately kicked in, and a happy wife makes a happy life ... lol ...

It seems that there may have been previous issues as when I removed the blower wheel there was a part that did not appear to be OEM that was holding the wheel on (See pictures)

My apologies but I did not take an image with the new wheel installed (forgot), but you can see what the new wheel looks like in the previous posting.

Also these are the remnants of the lower portion of the wheel. (Picture)

Lastly, there are 2 wires (one black & one White) that go to the Limit Switch, which is located at the back of the casing. Well these 2 wires are run inside of the casing and basically on top of the heating can, and my wires were melted, so I added 12" of wire to each and ran them outside the casing and to the limit switch. Again, this may be aftermarket work as the unit has to be removed to work on the wheel.

 

[wdk450]

In all the times I have read about furnace problems in Heartland RV's on the forum over the years, it seems like the sail switch has been at fault in 80-90% of those reports.

 

[Aryanna44]

In all the times I have read about furnace problems in Heartland RV's on the forum over the years, it seems like the sail switch has been at fault in 80-90% of those reports.

Will a bad sail switch prevent fan from blowing

 

[Dahillbilly]

Will a bad sail switch prevent fan from blowing

it will prevent ignitor from working & lighting the flame. Blower has to run for the sail switch to work. In the tools tab above you can find more info on troubleshooting furnaces