heater issue - painted sensor

[CarefreeLad]

Hi All,

So our propane heater works great in our 75 Carefree trailer, but it seems unaware of the inside temp and seems to be full blast all the time.

There is a copper (I think) tube style sensor outside the heater grill below the vents attached to the wall with a wire that runs back into the heater - someone spray painted it silver to match the grill they painted (chrome of course and that paint won't be staying on for long).

What I don't know is whether a painted sensor would/should still work or not. I would assume it shouldn't be painted, but figured I'd best check here with those with experience before I assume myself into a repair I may not need - perhaps I'm assuming a causal effect between paint and heater performance when there may be a different issue causing the heater issue.

Is there any info I can provide to aid in this quest?

Thanks in advance....and Happy New Year all

-Bryan

[Joe MacDonald]

pictures please?

[Friz]

The temperature range of heat on to heat off would be greater with the paint on the sensor but shouldn't stop it's operation. Paint will affect the transfer of heat from air to metal but not stop it. Scraping the paint off would help.

Sounds like you have a capillary sensor like on the water heater. These can go bad.

Have you tried using a hair dryer to heat the sensor and make it cut off the heat?
Is there an electric wire or small diameter metal tube from the sensor to the heater?
BTW is there a thermostat on the wall somewhere?

[CarefreeLad]

I figured the pics request would be coming ;-)

Thanks for the details Friz - hope the pics can confirm the type of sensor. I figured what you said - paint would alter the way it heats, but shouldn't outright stop it from working.

Details about the pics - 2 are the label so you can see who made it and what model - from Alberta which makes sense as this was built in Trail, BC.

The 3rd is the heater in a compartment under the closet - so that opening you see to it with the sensor underneath - about a foot off the floor. You can see the thermostat is in the compartment....so you'd think that would heat up quickly and flip off/lower the flame.

As Friz said - if it is a capillary sensor they can fail....so I suppose that may be a good place to start?

I haven't tried the hair dryer method, but I can give it a whirl this weekend. My "tests" have been simple and only done quickly while camping. I tried it on the low setting and hung out and read a book until I couldn't take it anymore (I do run super hot...so that alone doesn't mean it was "too" hot") - never lowered the flame.

Cheers

[Raspy]

That bulb and capillary tube control is designed to regulate the flame size based on the temperature of the bulb and the setting on the dial.

The bulb warms up and sends a hydraulic signal to the gas valve through the capillary tube. That signal is adjusted by the dial to control the flame size.

The system is very slow to respond, but should stabilize somewhat over time. The paint on the bulb means practically nothing.

When the system is running, see if you can adjust the flame size by turning the knob. If so, adjust it just high enough that the flame is on high. Then artificially heat the bulb and see if the flame reduces. Be careful not to apply too much heat to the bulb, it is designed to sense room temperature, not a hot flame. A sponge dipped in hot water, or a small heating pad would be more appropriate than a hair dryer. But a hair dryer on low and held carefully would be OK.

If you can't get the flame to adjust, the gas valve is bad. When working, the knob will directly control the flame size and the lower numbers mean a lower flame.

It would work much better if it also had a room thermostat. This would start and stop the flame, and the bulb would "anticipate" the heat requirement and regulate the fire to match the load. It would attempt to stop the system from overshooting. Together these two operations could work very well, but just the bulb control alone, not so much.

The knob should be adjusted so that the fire just achieves a comfortable temp, but this is a tricky point to find because of varying weather and intermittent heater use.

The system may be designed to use a wall thermostat, and I would look at it carefully to see if it can be set up that way. If not, it will be fully manual, so try to get the fire to reduce to a minimum when the temperature in the room is comfortable and after it has been on long enough to stabilize the bulb temperature.

Without a wall thermostat, it will never be very comfortable. Warmed room air must pass over the bulb for it to work at all.

I can't tell from you pictures if that bulb is inside or outside. If outside, it has even less control than if it is inside. A wall thermostat would significantly improve it.

[CarefreeLad]

Thanks Raspy,

I'm a systems guy, so knowing how it functions helps me a lot.

Thanks for the testing methods - all understood and make sense.

The sensor is on the outside of the closet cabinet - feeds behind the edge of the grate which you have to open to light it and is attached just below that grate on the "wall" a foot off the ground or less).

I assume when you say I'd have more control with that sensor inside would be because it should heat up faster? Would make sense - of course I don't know if it is in it's original location now or not ....but maybe a move inside.

Testing first to see what's what - I'll report back once I have a chance (and I'll use the hot water or heating pad - have both).

I'll also see if I can find any specs on the heater - maybe they'll touch on whether I can hook in a wall mounted thermo.

That said....I doubt our usage will have the heater on for extended periods of time. We don't camp in truly cold whether - I'm on Vancouver Island and what we get is rain. More to warm the thing up at bed time - bedding keeps us plenty warm. Of course it would be nice to know I can wander off for 10 minutes with it on and it won't start melting the closet rod

Thanks again!

[Raspy]

Bryan,

By "inside" or "outside", I mean inside the trailer, or outside the trailer. I don't mean the bulb should be inside the burner area.

If the bulb is outside the trailer, it is simply an anticipator that tries to adjust the flame to compensate for the outside temp. Seems ridiculous, I know, but that is the theory.

Inside the living space, the bulb has a chance to feel the inside temp and adjust the fire, but it is very poor at that because it is slow reacting and not in a very good spot.

If you have to change the gas valve, don't worry about getting one with that modulating feature, if it's not available. But get one that has thermostatic control.

That design can either have electronic ignition or a thermocouple. The thermocouple design is simpler, but the pilot must remain on if there is a chance of calling for heat. The thermocouple design also needs no power to function, so it retrofits into older heaters well. The new thermocouple would probably fit into the existing bracket you have now and get bathed by the pilot light.

A simple mechanical thermostat is all that is needed to control it. Or you could put a battery operated one with digital readout. But either way, no power is needed to the thermostat.

[wilyoung]

That bulb and tube are part of the thermostat system. The bulb senses the room temperature, warmer bulb - higher pressure in the bulb. If you put it inside the heater it will sense heater temperature, not room temperature. The knob controls how high, or ON/OFF, the flame depending on the pressure in the bulb-tube. There is something preventing this system from working. Could be a leak in the bulb, tube, or pressure sensing system attached to the knob. Could be something preventing the knob from controlling the pressure sensing system. Could be a problem of something "sticking" in the pressure sensing system because of rust, gunk, or whatever (something has to move to sense pressure). In such an old system no telling what may be wrong.


A good tech should (may) be able to diagnose the problem. Finding parts may be a problem. If the heater itself is worth it maybe install a whole new thermostat system. If the trailer is worth it and there's room maybe install a modern RV furnace.


Good luck.


Wil

[CarefreeLad]

Originally Posted by Raspy

Bryan,

By "inside" or "outside", I mean inside the trailer, or outside the trailer. I don't mean the bulb should be inside the burner area.

If the bulb is outside the trailer, it is simply an anticipator that tries to adjust the flame to compensate for the outside temp. Seems ridiculous, I know, but that is the theory.

Inside the living space, the bulb has a chance to feel the inside temp and adjust the fire, but it is very poor at that because it is slow reacting and not in a very good spot.

If you have to change the gas valve, don't worry about getting one with that modulating feature, if it's not available. But get one that has thermostatic control.

That design can either have electronic ignition or a thermocouple. The thermocouple design is simpler, but the pilot must remain on if there is a chance of calling for heat. The thermocouple design also needs no power to function, so it retrofits into older heaters well. The new thermocouple would probably fit into the existing bracket you have now and get bathed by the pilot light.

A simple mechanical thermostat is all that is needed to control it. Or you could put a battery operated one with digital readout. But either way, no power is needed to the thermostat.

Ahh...yes...inside the living space....but yeah being that close to the floor will take a long time to sense the heat....so that is probably the biggest issue - placement. Of course it may also be toast and in need of replacement - testing should prove that out.


BTW...it has a thermocouple - tough to start due to the time to heat it up from dead cold - subsequent lights the same day seem to be much quicker. I'm not one for fancy....more for bullet proof - thermocouple it shall stay ;-)

[CarefreeLad]

Originally Posted by wilyoung

That bulb and tube are part of the thermostat system. The bulb senses the room temperature, warmer bulb - higher pressure in the bulb. If you put it inside the heater it will sense heater temperature, not room temperature. The knob controls how high, or ON/OFF, the flame depending on the pressure in the bulb-tube. There is something preventing this system from working. Could be a leak in the bulb, tube, or pressure sensing system attached to the knob. Could be something preventing the knob from controlling the pressure sensing system. Could be a problem of something "sticking" in the pressure sensing system because of rust, gunk, or whatever (something has to move to sense pressure). In such an old system no telling what may be wrong.


A good tech should (may) be able to diagnose the problem. Finding parts may be a problem. If the heater itself is worth it maybe install a whole new thermostat system. If the trailer is worth it and there's room maybe install a modern RV furnace.


Good luck.


Wil

Thanks for the list of parts of the thermo system that may have issues - learning as I go! As for worth it and/or going modern - 14 ft trailer from 1975. it beats a tent and doesn't need to be fancy or super convenient due to limited use - just not that cold here - ever. We won;t be traveling off the island any time soon. As I said in reply to Raspy - I like bulletproof over bells and whistles. So I lean to low tech - less to break!!

[wilyoung]

Google "Hydro Flame Furnace Model BRC-10A", without the " of coarce, and you will find lots of sites with info.


Wil

[CarefreeLad]

Originally Posted by wilyoung

Google "Hydro Flame Furnace Model BRC-10A", without the " of coarce, and you will find lots of sites with info.


Wil

Thanks Will - I just hadn't found the time to look yet, but had hoped there'd be more info about the appliances in it then there is about Carefree trailers (which is basically nothing of use). For what it's worth I own a software company and have been building web applications since the mid-90s - got the Googling down pat LOL.


Have a great weekend!


Cheers

[Raspy]

Bryan,

The thermocouple is not the problem, but the pilot being hard to stay lit is beginning to reveal a problem. Either the gas valve is getting stiff, or the t-couple is getting weak.

Since it is a t-couple system, it is similar to any propane wall furnace and the gas valve and t-couple from one of those would most likely fit and work just fine. Parts are readily available for generic furnaces, if you can't get exact replacement parts for your model. Just be sure, if you start to replace stuff, and especially if you upgrade, that you are aware of what you are doing and how to set it up correctly. For instance, the T-couple must be in the pilot flame, and not affected by the main flame. And, of course, with a system that old, there must not be any cracks in the combustion area that could allow CO into the living space. The vent to the outside and the combustion air supply must be correct.

I'd try to upgrade to a fan forced system that gets its combustion air from outside and vents it's exhaust to the outside through a sidewall vent. More modern, efficient and readily available. Plus they stir the air and heat more evenly.

[CarefreeLad]

Originally Posted by Raspy

Bryan,

The thermocouple is not the problem, but the pilot being hard to stay lit is beginning to reveal a problem. Either the gas valve is getting stiff, or the t-couple is getting weak.

Since it is a t-couple system, it is similar to any propane wall furnace and the gas valve and t-couple from one of those would most likely fit and work just fine. Parts are readily available for generic furnaces, if you can't get exact replacement parts for your model. Just be sure, if you start to replace stuff, and especially if you upgrade, that you are aware of what you are doing and how to set it up correctly. For instance, the T-couple must be in the pilot flame, and not affected by the main flame. And, of course, with a system that old, there must not be any cracks in the combustion area that could allow CO into the living space. The vent to the outside and the combustion air supply must be correct.

I'd try to upgrade to a fan forced system that gets its combustion air from outside and vents it's exhaust to the outside through a sidewall vent. More modern, efficient and readily available. Plus they stir the air and heat more evenly.

The pilot stays lit just fine - I turn it OFF when I will not be near the trailer is all. That's why I light it multiple times in a day - not because it goes out.


Mine does vent to the outside - so much so that if you hold a damp kitchen towel up to it, the steam comes off it almost instantly! What I have not confirmed is if part of the exterior vent is also sucking in air or if that comes from inside only. There is a single external grill - there may be 2 holes behind it not just one for venting to outside.


I don't think I'm at the toss it for a new one stage - if it dies and parts are hard to find - then I jump ship for something more standard as you suggest. Heck man....I'm trying to find a lid for my thermal mug cause I hate throwing things out that still work if they can be fixed - I'm 15 years in with that mug and I'll be damned if I toss it just cause the plastic lid finally cracked ;-)


I'm still going to test to confirm if in fact that thing does or does not alter the flame with heat directed to the bulb sensor. If that doesn't have any effect, I'll consider some removal and inspection to see if I can find any of the other parts Will mentioned could be the issue. If that starts to look ugly....might be time to upgrade.


Hey...the best part of going through this stuff is you eventually know every bit of your trailer and can diagnose and fix in a heartbeat in future right! That and like I mentioned - I'm a systems guy - sure that's software during the day, but systems are everywhere and I do love making stuff work. I was the kid that took the phone apart to see how it worked...and everything else I could take apart...hehe