FMI TV2000 (1994) not staying lit

[watson524]

Hi all, The background...
trying to help a friend of mine with her natural gas fireplace. It's a 1994 Fireplace Manufacturers Incorporated TV2000. No blower in it and has the low voltage wall switch. She said last year she was having trouble with it and over the summer, she noticed the pilot had gone out (they just keep it on year round). Instead of her messing with it, I just told her to turn the knob to off and shut the gas off until I got to look at it. Schedules aligned and I went down yesterday to take a look.

Noticed that there are two black wires, one off the back of the control valve and another off the TH/TP screw but they are jumpered together. Didn't think much of that at this point. Turned gas on, turned knob to pilot, held in for enough time to purge air, hit the igniter button and got a pilot in 2 clicks. Held button in about 45 seconds before turning to on, pilot stayed lit. Hit wall switch, took longer than I think it should have (20 - 30 seconds) but flame came on and looked like a nice blue as expected. I bent down to tuck those 2 black wires up in and the flame went out. Turns out whoever jumpered them just had the female end of a spade connector on the black and then used a short piece of wire to go into one side of each of the spade connector female "loops" and it was loose. Ok so figure that's why it went off. Used a pliers to really crunch the female spades down to keep that tight (more on this later) and went through the process of relighting. Got it lit, talking for a few minutes, burner flame off but right back on. Kept talking, went out and stayed out. Relights ok, but burner won't stay lit.....

So now, things I know/think/questions:
1.) Why those wires are jumpered I'm not sure. I was able to find a manual on line and I believe those are supposed to be to some kind of micro safety switch that possibly wouldn't allow it to be lit without the glass in place. I mentioned this because in the manual it mentions pulling the glass panel straight out until "assembly is free from safety switch arm (located in the middle of the appliance above the lower louver)". When she took the lower louver off, I noticed behind the lower brass trim what looked like a bracket of sorts but wasn't really supporting or doing anything. I'm wondering if maybe it was giving issues in the past (her husband used to deal with all this stuff but he's now deceased) and someone decided to just jumper it. I know you shouldn't run the fireplace without the glass in place, but let's say you're working on it and testing flame setup, cleaning thermopyle to check things..... IS it EVER ok to run it without the glass in place or even during servicing to you keep screwing glass in and out?
2.) Does the behavior of the fireplace not staying lit seem like it is the thermopyle? I didn't have my multimeter with me to test it but I figured next time I'm down I'll bring it to test. What is the procedure for testing? I've read different things of pilot on for 2 minutes, take a reading, burner on, take a reading (should be some drop?), etc. I just want to make sure I'm doing it right. Probes on TH/TP and TH and then what.....
3.) If it's a thermopyle issue, is it worth it to try to clean it with some fine sandpaper or something?
4.) Pending the answer to number 3, do they have to be bought as a whole unit? The book has part number 202873 but that's the whole pilot assembly with pilot gas line, pilot, ignitor and thermopyle all on one bracket. Not even sure I can track down that part but do I need all of it? I didn't take the glass off and logs out to see how it's mounted in there, not even sure if the mountings are universal or not. I do see JUST thermopiles (750mV) online for sale, and it looks like they just thread in through the bracket (I assume there's some adjustment to get the top of it to 3/8" - 1/2" height above the pilot flame per the manual specs)
5.) The wall switch seems to take too long to fire the burner, could that be because of a bad thermopyle not sending out enough voltage right away?
6.) I told her if I thought it was anything with the gas coming in, I wouldn't mess with it and she'd have to call an actual repair place, but for someone that's handy, are there concerns with me messing with the pilot gas line (i.e. if I had to replace the whole assembly as they seem to come down the pilot gas line). I assume they're compression fittings so you don't teflon tape them or anything like that and obviously I'd shut the gas off.

Thank you all in advance! I'm just trying to help a friend out so hopefully this isn't something too crazy

 

[Lennox65]

Hi all, The background...
trying to help a friend of mine with her natural gas fireplace. It's a 1994 Fireplace Manufacturers Incorporated TV2000. No blower in it and has the low voltage wall switch. She said last year she was having trouble with it and over the summer, she noticed the pilot had gone out (they just keep it on year round). Instead of her messing with it, I just told her to turn the knob to off and shut the gas off until I got to look at it. Schedules aligned and I went down yesterday to take a look.

Noticed that there are two black wires, one off the back of the control valve and another off the TH/TP screw but they are jumpered together. Didn't think much of that at this point. Turned gas on, turned knob to pilot, held in for enough time to purge air, hit the igniter button and got a pilot in 2 clicks. Held button in about 45 seconds before turning to on, pilot stayed lit. Hit wall switch, took longer than I think it should have (20 - 30 seconds) but flame came on and looked like a nice blue as expected. I bent down to tuck those 2 black wires up in and the flame went out. Turns out whoever jumpered them just had the female end of a spade connector on the black and then used a short piece of wire to go into one side of each of the spade connector female "loops" and it was loose. Ok so figure that's why it went off. Used a pliers to really crunch the female spades down to keep that tight (more on this later) and went through the process of relighting. Got it lit, talking for a few minutes, burner flame off but right back on. Kept talking, went out and stayed out. Relights ok, but burner won't stay lit.....

So now, things I know/think/questions:
1.) Why those wires are jumpered I'm not sure. I was able to find a manual on line and I believe those are supposed to be to some kind of micro safety switch that possibly wouldn't allow it to be lit without the glass in place. I mentioned this because in the manual it mentions pulling the glass panel straight out until "assembly is free from safety switch arm (located in the middle of the appliance above the lower louver)". When she took the lower louver off, I noticed behind the lower brass trim what looked like a bracket of sorts but wasn't really supporting or doing anything. I'm wondering if maybe it was giving issues in the past (her husband used to deal with all this stuff but he's now deceased) and someone decided to just jumper it. I know you shouldn't run the fireplace without the glass in place, but let's say you're working on it and testing flame setup, cleaning thermopyle to check things..... IS it EVER ok to run it without the glass in place or even during servicing to you keep screwing glass in and out?
2.) Does the behavior of the fireplace not staying lit seem like it is the thermopyle? I didn't have my multimeter with me to test it but I figured next time I'm down I'll bring it to test. What is the procedure for testing? I've read different things of pilot on for 2 minutes, take a reading, burner on, take a reading (should be some drop?), etc. I just want to make sure I'm doing it right. Probes on TH/TP and TH and then what.....
3.) If it's a thermopyle issue, is it worth it to try to clean it with some fine sandpaper or something?
4.) Pending the answer to number 3, do they have to be bought as a whole unit? The book has part number 202873 but that's the whole pilot assembly with pilot gas line, pilot, ignitor and thermopyle all on one bracket. Not even sure I can track down that part but do I need all of it? I didn't take the glass off and logs out to see how it's mounted in there, not even sure if the mountings are universal or not. I do see JUST thermopiles (750mV) online for sale, and it looks like they just thread in through the bracket (I assume there's some adjustment to get the top of it to 3/8" - 1/2" height above the pilot flame per the manual specs)
5.) The wall switch seems to take too long to fire the burner, could that be because of a bad thermopyle not sending out enough voltage right away?
6.) I told her if I thought it was anything with the gas coming in, I wouldn't mess with it and she'd have to call an actual repair place, but for someone that's handy, are there concerns with me messing with the pilot gas line (i.e. if I had to replace the whole assembly as they seem to come down the pilot gas line). I assume they're compression fittings so you don't teflon tape them or anything like that and obviously I'd shut the gas off.

Thank you all in advance! I'm just trying to help a friend out so hopefully this isn't something too crazy

The door switches were a horrible design and thankfully discontinued. Yes you can run it without the glass for testing but during normal operation the glass needs to be securely in place.

The fireplace not staying lit is probably either the thermopile or the wall switch. If it is the original thermopile, just replace it. Sanding can help a little but I have never seen dramatic results from sanding. You should have around 450-500 Mv with the pilot lit and the wall switch off. Once the main burner is lit, the Mv should drop by about half. 150 Mv with the main burner on is about as low as it can go and still hold the burner open.

If the rest of the pilot assembly is in good condition, you can just replace the thermopile but I almost always replace the entire pilot assembly.

The delayed ignition could be related to the thermopile, wall switch or wiring. But it could also be a partially clogged burner. Do you hear a click at the valve immediately when you turn on the wall switch? If so, it is not the thermopile and probably something with the burner tray/pan.

 

[watson524]

The door switches were a horrible design and thankfully discontinued. Yes you can run it without the glass for testing but during normal operation the glass needs to be securely in place.

The fireplace not staying lit is probably either the thermopile or the wall switch. If it is the original thermopile, just replace it. Sanding can help a little but I have never seen dramatic results from sanding. You should have around 450-500 Mv with the pilot lit and the wall switch off. Once the main burner is lit, the Mv should drop by about half. 150 Mv with the main burner on is about as low as it can go and still hold the burner open.

If the rest of the pilot assembly is in good condition, you can just replace the thermopile but I almost always replace the entire pilot assembly.

The delayed ignition could be related to the thermopile, wall switch or wiring. But it could also be a partially clogged burner. Do you hear a click at the valve immediately when you turn on the wall switch? If so, it is not the thermopile and probably something with the burner tray/pan.

Thank you for the input!! Since that safety switch isn't hooked up and just jumpered, I'm going to put them together with a more secure wire nut or butt connector (I'm partial to the positap connectors).

I just called the manufacturer (which is apparently out of business and sold to someone else). The gentleman on the phone said all the old FMI fireplaces didn't just have a thermopile part, it was the whole assembly you replaced but there's no where to get parts any more?? He suggested sanding/scotch pad to maybe get some time out of it which I'll try. So that being said, I asked if the bases on thermopiles were universal and he said he didn't know. I've seen lots on amazon that are 750mV with varying length wires to them and would worry about voltage drop if I went too long. It seems 24" and 36" are the most common so I'd assume 24" BUT I don't know if the base that screws into the bracket is a universal size where I could screw in the new or possibly even leave the old "bushing" in place and just drop the new thermopile and wires through.

If I have to replace the pilot assembly it sounds like that's an issue since there's no parts available but even if there was, is it safe for me to be messing with the pilot gas tubing? I mean, it's not like i'll light a match next to it so I think it's ok but....

As for a click with the wall switch, I didn't hear anything but honestly, her granddaughter was there talking so I don't know if I would have anyway. I know when I hit the remote on mine, I do hear that click you're talking about.

What's the best way to test the wall switch and are those universal? I'm thinking with pilot/gas off, put the wall switch in the on position and test for continuity down in the unit across the two terminals as a start. Are the wall switches universal?