Trillium Furnace Quit

[David Tilston]

Originally Posted by Joe MacDonald

Don’t push something through the orifice that will definitely ruin it Cleaning with alcohol or brake cleaner may open it up, use that stuff only outside the trailer, well ventilated area.
Allow to dry at least a day before bringing a flame near it

Joe

Joe, I have seen other people say that as well. I am not sure I understand. The orifice is brass, so softer than steel, but if a wire that is smaller than the orifice, (like a stripped twist tie) is pushed through, (gently) what problem does that cause?

[Thomas W]

Success! Decided to dismantle the furnace, came out quite easily. When it was pulled out far enough to clear the cabinet I rotated it 90 degrees and propped it up so I could remove the plate easier and not have to slide the exhaust all the way out, then worked on the assembly indoors. Dismantled the burner, full of rust dust. Tried briefly to remove the orifice but it was tight. Blasted it several times with an electronics cleaner, no residue and it evaporates quickly. Then inserted an unsheathed twist tie wire which was about 1/2 the diameter of the orifice, no resistance. Reassembled for a test and Voila! it worked!
Feeling much better about using it after I see how it has a separate intake, exhaust and sealed burner unit.
Also re discussion of thermostat, this is a 65512-00 Duo Therm and I am sure this was the first time it was disassembled and was original in my 1980 4500. My Duo Therm 'manual' references unit with and without a thermostat. I have pics but havent figured how to post yet

[Thomas W]

[David Tilston]

Good job!

There is a bit of rust, but I think your furnace is in excellent condition. Typically when I disassemble one of these furnaces, at least one of the studs gets sheared off due to corrosion. It looks like all of yours are clean.

The next test I would do is to ensure that the furnace turns off. I assume that you had to short out those two terminals on the gas valve to get it to go. I wonder how long it takes to go from on to off, and vice versa. I want to know the model number of your gas valve more than ever now.

When I rebuild reassemble a Duo-Therm furnace, I paint the burner, and the combustion air intake, on the back of the fire box, with high heat paint. Both of those are where I find the most rust. If you do paint the burner, cover up the slots that the flame comes out of. That is stainless steel, and won’t rust. You don’t want paint plugging up those vents.

You will need some high temperature gasket material to close it up. I am not sure how the exhaust / intake air vent extension is going to look like, but if it is still a sliding concentric affair, I suggest some high temp anti seize compound to prevent it fusing with rust.

[Thomas W]

Per my previous post: Also re discussion of thermostat, this is a 65512-00 Duo Therm and I am sure this was the first time it was disassembled and was original in my 1980 4500. My Duo Therm 'manual' references units with and without a thermostat.
The thermostat is on the wall by the bed and connects to the furnace at the two terminals below the red pilot valve (the little plate says 'therm' on it). To test it I just reconnected the thermostat wires to it and turned it up, it works like one of those 30 year old house thermostats. If you look back on these posts one of them mentions a 'boink' when the thermostat turns on. I dont know if that actually generates a little voltage or if it just closes the circuit but thats what turns on the main gas valve.
I was careful with the nuts, using penetrating oil, loosening, backing off, cleaning, repeat.
Perhaps its in better shape cause its been garaged for the last 9 years. I'll clean it up and reseal properly but I'm not painting, chimney was snug, better to let sleeping dogs lie.

[David Tilston]

I was asking about the gas valve, not the thermostat. I believe it is manufactured by ITT. The model number is printed on the side of the valve.

Also, it is my understanding that having an actual thermostat requires a thermopile vs a thermocouple, (more power). This may mean that you can’t use the part that I linked to. Could you please post some close up pictures of the gas valve, and the pilot light assembly?

[canyon Rafter]

A word of advice....Don't try to clean out the parts with compressed air. The compressed air can cause gadgets to leak or disintegrate, or simply blow out in places where you had no problem before. I made this mistake with my thermostat on the magic chef oven. I thought I could just go and buy a new thermostat but they are no longer manufactured, as a result I spent a couple days figuring out how to rebuild the thing. If you use compressed air use the small dust cleaning aerosol cans, they clean but don't have a lot of pressure.

[Thomas W]

I ended up pulling the whole unit out so I could clean everything and reseal the inspection plate and burner connection. The outer exhaust droops about 1/2 inch. Is there any trick to line it up with the inner exhaust without taking off the outer grill?
I did get some pics of the gas valve, unfortunately the markings are not very clear. The upper left number might be 76 14 8, the one on upper right looks like 136 with a circle around it, the others are not legible.

Sorry about the thermocouple pics, I reassembled before I saw your note. But if you go back to my previous pics it does show the pilot and thermocouple. Looks pretty similar to what I have seen in previous pics.

[Chris from Comox]

From personal experience, it’s easier to remove the outer grill, remove what I call the “chimney”, put the furnace in place then wiggle/slide the “chimney” into the furnace itself and reinstall the outer grill.. The reason being that the “chimney” is a lot easier to wiggle around , has less sharp edges and is lighter than furnace itself. And you are not “blind” to the whole process as you can sort of see how everything is lining up at the same time

[Thomas W]

I got it all back together and tested it, furnace comes on about 5 seconds after thermostat is tripped.
To prop up the chimney I used a plastic strip used to unclog drains (see pic) inserted in the air intake and then run vertically up to the chimney. Eyeballed where it looked straight and then taped the plastic strip down to hold it. Went right in first try.
Re the pilot/thermocouple David, it is identical to the picture of the 65512 you posted. Ooops the second pilot pic should be rotated 90 deg to right
Thanks again everyone for you help, I was really happy to save this furnace, and learned a lot about in the process.

[David Tilston]

Originally Posted by Thomas W

I ended up pulling the whole unit out so I could clean everything and reseal the inspection plate and burner connection. The outer exhaust droops about 1/2 inch. Is there any trick to line it up with the inner exhaust without taking off the outer grill?
I did get some pics of the gas valve, unfortunately the markings are not very clear. The upper left number might be 76 14 8, the one on upper right looks like 136 with a circle around it, the others are not legible.

Sorry about the thermocouple pics, I reassembled before I saw your note. But if you go back to my previous pics it does show the pilot and thermocouple. Looks pretty similar to what I have seen in previous pics.

Thanks. I guess the model number will remain a mystery.

The previous pictures were also from a thermostat version of the gas valve. Below is what the business end of a standard thermocouple looks like.

The picture is from this thread:
https://www.fiberglassrv.com/forums/...tml#post295738
The pilot light is the top protrusion. There is a piece on the end that deflects the flame downward to the thermocouple. Note how thin it is in comparison to yours.

I have been looking into where to get a replacement thermopile. From this thread:
https://www.fiberglassrv.com/forums/...tml#post616381
I found this picture:

Which lead me to the following links:
https://www.americanhvacparts.com/p-...e-rodgers.aspx
https://www.americanhvacparts.com/p-...cartridge.aspx
They are not cheep.
Cheaper on Amazon:
https://www.amazon.ca/s?k=thermopile&ref=nb_sb_noss_1

[Thomas W]

Ok, I think I get it now. That seems unusual that the pilot's flame is deflected downward to the thermocouple, and yes it is thinner than mine. Had not heard the term thermopile before but makes sense that its a grouping of smaller units. And yes, my pilot is below the thermopile.

Has your paint job on the burner held up over time? How did you clean it up prior to painting? While mine had a lot of surface rust it seemed quite solid. I may change my mind in the future about painting.

Yeah, unfortunate that there were no other markings or stampings on the gas valve. My friend has a 1300 and he tossed the furnace a few months after he got it because it quit and he wanted to go a different way. These should be salvaged as they go bad or trailers are abandoned.

[David Tilston]

I gave it a light sanding to knock off the larger chunks of rust, but otherwise I didn’t do much prep work. I used black RUST-OLEUM high temperature paint. I figured it was meant for rusty surfaces.

The paint is inside the furnace. I don't get a good look at it much. Since I used black paint, I never noticed any problem with it. But I didn't worry about it much, since any burnt paint would just go out the exhaust. The combustion air intake on the back of the fire box is both below the fire, and constantly cooled by fresh air. No issues at all. I only painted the outside of the burner. I couldn’t see any way to do the inside of the burner, without plugging up the holes. I used masking tape on the stainless piece that has the holes for the burner. I painted both the inside and the outside of the fresh air intake, but I taped off the mating surface that connects it to the housing. I didn't want to affect the fit of that joint.

There are many threads on this site that discuss how hard it is to get the two pieces of the vent apart. The inner tube rusts to the point that they fuse and no longer slide apart. Many of these furnaces have been destroyed in the process of removing them. I would also suggest using some high temperature anti seize compound where the two hot parts slide against each other. This will make is much easier to remove your furnace in the future.

If your friend had advertised the gas valve from his furnace here, I would have paid $100 plus shipping for it.

I am not so sure that your pilot is below the thermopile. The silver tube is for the pilot light. The flexible wire is the thermopile. The pictures that you posted seem to show the tube above the wire. The big tube is for the main burner, and is on the bottom.

[canyon Rafter]

Good job Thomas! Glad you got your heater working again! I stayed in my Fiber Stream trailer for an extended period of time and found that my furnace heater was way too loud during the night and ended up heating the trailer with an electric heater. I had hookup to electricity so that was an easy solution. My next heater will be a Mr. Heater MH9BX- or something similar. Safe vent less heater that can easily be plumed into the propane gas lines of the trailer. Easy safe heat.

[Joe MacDonald]

The reason to not push anything through the opening is that even if it is smaller than the opening, a steel wire is harder than the orifice plate and can potentially damage it, I suppose a nylon bristle might be ok, on our burners at work we replace the orifice plate on smaller heaters, on our big ones, we drill them with a drill sized to the holes in the cast iron burners or stainless burner plates
Joe

[David Tilston]

Originally Posted by Joe MacDonald

The reason to not push anything through the opening is that even if it is smaller than the opening, a steel wire is harder than the orifice plate and can potentially damage it, I suppose a nylon bristle might be ok, on our burners at work we replace the orifice plate on smaller heaters, on our big ones, we drill them with a drill sized to the holes in the cast iron burners or stainless burner plates
Joe

Yes, I see the potential for damage to the orifice. Why is brass the common metal for this application?

Since you are professionally involved with heaters, any idea where I would go looking for new orifices for the Duo-Therm furnaces? With a 3/4" hex head, (I think) they seem larger than I expected, but I am used to motorcycle orifices that have a 1/4" hex head.

I like spare parts, and I would like to locate a smaller orifice for use at higher altitudes.