Heater issues

[Baguak]

I have a 2015 fifth wheel carbon. I have a propane heater. When hooked into shore power it works fine. When running off battery my rig fills with carbon monoxide. What on earth is the reason for this???

Thanks!


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[chuckster57]

Is it setting off the detector? If it’s a combo LP/carbon monoxide detector then it’s possible that the battery(s) are weak enough to drop below the threshold. If I remember right, it’s about 11.5VDC, May be enough to spin the furnace fan but not enough to stay above the threshold.

[travelin texans]

Your furnace is 12 volt regardless if hooked to shore power, if on shore power it's running off the converter which is also charging the batteries, hopefully.
My guess is you have weak batteries as they will chirp the LP/CO sensor.

[Baguak]

Your furnace is 12 volt regardless if hooked to shore power, if on shore power it's running off the converter which is also charging the batteries, hopefully.
My guess is you have weak batteries as they will chirp the LP/CO sensor.



It is a definite smell and not a faulty sensor. Doesn’t happen on shore power and does on battery.


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[Baguak]

Is it setting off the detector? If it’s a combo LP/carbon monoxide detector then it’s possible that the battery(s) are weak enough to drop below the threshold. If I remember right, it’s about 11.5VDC, May be enough to spin the furnace fan but not enough to stay above the threshold.



Can you please explain “threshold” to me? The batteries would be weakened over the course of the night. If they are, how will this effect the rig in that I smell CM? Thanks!


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[dcg9381]

There's a minimum battery voltage, consider it the "oh crap" voltage where the detector should start alarming. Just like when there is a low battery or power outage at your house with modern smoke detectors.

This "could" be it. I have a 2015 Carbon and unless you've taken a good deal of care of your batteries OR have replaced them recently, then the batteries can easily be toast after a few total discharges.

You should have a battery status indicator. Unplugged from shore power, what does it say about the condition of the battery?

And you smell propane - not carbon monoxide. So something is open, which again, indicates that the furnace is "trying" to do something but cant...

[Baguak]

There's a minimum battery voltage, consider it the "oh crap" voltage where the detector should start alarming. Just like when there is a low battery or power outage at your house with modern smoke detectors.

This "could" be it. I have a 2015 Carbon and unless you've taken a good deal of care of your batteries OR have replaced them recently, then the batteries can easily be toast after a few total discharges.

You should have a battery status indicator. Unplugged from shore power, what does it say about the condition of the battery?

And you smell propane - not carbon monoxide. So something is open, which again, indicates that the furnace is "trying" to do something but cant...



Your last statement makes sense. They are not beeping from loss of power that is for sure. “Trying to do something but can’t” feels like what is happening. I wonder what it could be trying to do that
A: it can do on shore but not battery
B: would cause the unit to smell like propane
C: goes away when I plug back into shore


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[dcg9381]

What is your battery voltage after you've unplugged the rig for a few hours?
I think a few of us "suspect" the battery - because mostly discharged batteries can do all sorts of weird things which wouldn't otherwise be possible.

Maybe someone else can chime in on how the propane valve on the heater should work? Is it a power-to-open thing? IE - does it auto shutoff in a hard power down?

[chuckster57]

For the furnace to operate:

12VDC to control board. First is through the “limit switch” (over heat), after that is the “sail switch”. A long arm that is in the fan housing, takes a minimum amount of air flow to pass that test (switch). After that, power is applied to the gas valve..power to the igniter. Once lit, the flake sensor keeps the valve open until set temp. Once set temp is reached, gas valve is closed and unit goes into “cool down” mode. Fan spins for a predetermined amount of time.

[dcg9381]

chuckster57, Are the gas valves "normally closed"? Meaning you need active power to keep them open?

[Baguak]

chuckster57, Are the gas valves "normally closed"? Meaning you need active power to keep them open?



Gas valves?


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[Baguak]

chuckster57, Are the gas valves "normally closed"? Meaning you need active power to keep them open?



That I don’t know.


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[ctbruce]

Gas valves?


Sent from my iPhone using TapatalkJust like your house, your furnace in your Rv has valves as well. Why are you unplugging from shore power?

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[JRTJH]

The gas valve is "spring loaded" to the closed position (which is its normal state) and requires 12 VDC through the limit switch and the sail switch before voltage is applied to the gas valve to open it. If you think about it, if the gas valve was "normally open" or if it operated in any other way, if you disconnected your battery, the gas valve would open causing a propane leak.

[travelin texans]

After all the other discussions it still sounds like weak/bad batteries to me.

[JRTJH]

After all the other discussions it still sounds like weak/bad batteries to me.

I agree. Based on the OP's first post: "When hooked into shore power it works fine. When running off battery my rig fills with carbon monoxide"

It sounds like what he is saying is that with the converter supplying power, everything works as it should, when he unplugs, the battery voltage is lower than it should be, the furnace draws that down even more and the Carbon Monoxide detector (which is connected to battery power) alarms because of low voltage. The rig can't be "filled with carbon monoxide" while on battery and working properly when on shore power, the furnace fire box doesn't know which power source is being used and that's the primary source of CO for that appliance.....

[sourdough]

Although it's been covered, I'll have to chime in here and say batteries. The OP needs to do a thorough inspection of them and let us know what state they are in.

[flybouy]

There's a minimum battery voltage, consider it the "oh crap" voltage where the detector should start alarming. Just like when there is a low battery or power outage at your house with modern smoke detectors.

This "could" be it. I have a 2015 Carbon and unless you've taken a good deal of care of your batteries OR have replaced them recently, then the batteries can easily be toast after a few total discharges.

You should have a battery status indicator. Unplugged from shore power, what does it say about the condition of the battery?

And you smell propane - not carbon monoxide. So something is open, which again, indicates that the furnace is "trying" to do something but cant...
This is correct as CO is colorless and odorless hence the "silent killer" label.

[Baguak]

Although it's been covered, I'll have to chime in here and say batteries. The OP needs to do a thorough inspection of them and let us know what state they are in.



When I disconnected power and tested two batteries registered 13 volts while the third registered 12.


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[Baguak]

This is correct as CO is colorless and odorless hence the "silent killer" label.



I agree with the CO comment. I just noticed it is a CO/propane alarm and when it went off I didn’t realize which light was on. I am going to assume propane from the the comments in the thread.

Simone else pointed out the power needed for valves to switch over or something like that. I think the rig just ran out of enough power perhaps.


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[JRTJH]

When I disconnected power and tested two batteries registered 13 volts while the third registered 12.


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Did you run the furnace and test the voltage after about 15 minutes with the furnace still operating? Many "weak" batteries will read over 12 VDC when first removed from a charger and with no load, but they will rapidly lose their charge with a small load and will read 11 VDC or less in a very short time.

Typically, a fully charged operational battery will read about 12.6 VDC an hour after being removed from the charger. If two of yours were reading 13 VDC and one was reading 12 VDC, you may have a bad battery that's pulling the other two "down" preventing all three from fully charging. Or, you could have a different problem....

In any situation, if the system works when on shore power and does not work on battery power, it's not the propane, furnace or CO monitor that's at fault, it's the power source which is the only thing that has changed between being "plugged in and running on batteries".

[Baguak]

Did you run the furnace and test the voltage after about 15 minutes with the furnace still operating? Many "weak" batteries will read over 12 VDC when first removed from a charger and with no load, but they will rapidly lose their charge with a small load and will read 11 VDC or less in a very short time.



Typically, a fully charged operational battery will read about 12.6 VDC an hour after being removed from the charger. If two of yours were reading 13 VDC and one was reading 12 VDC, you may have a bad battery that's pulling the other two "down" preventing all three from fully charging. Or, you could have a different problem....



In any situation, if the system works when on shore power and does not work on battery power, it's not the propane, furnace or CO monitor that's at fault, it's the power source which is the only thing that has changed between being "plugged in and running on batteries".



This is highly logical. The batteries are two years old minimum and I want to switch out to 6v anyways so this will give me a reason to do so!

As always, I am appreciative of your help


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[travelin texans]

Check the voltage on the batteries unplugged at the time the CO sensor starts chirping, I'd bet an adult beverage that they won't be 12-13 volts at that point. Static they may read 12 volts, but not under load.
Other than turning on every light in your rv at once the furnace blower is the biggest 12 volt draw & also a huge propane hog.