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wornways 12-10-2009 08:15 AM

Pilot on Williams millivolt wall heater goes out every 8 to 16 hours
 
Hi folks,

I created this account for the sole purpose of seeking help with this problem, which I'm beginning to think is unsolvable or something to do with ghosts.

I live in a rental with a Williams millivolt wall heater. When I first moved in last March, the pilot went out about every 3 to 4 days like clockwork. I was busy and warmer weather was on the way, so I didn't problem it. By the time I shut off the heater for the summer months, however, the pilot was going out every 2 to 3 days.

Three months ago I relit the pilot and began using the heater. Now the pilot was going out about every 1 to 2 days. And also now, sometimes between outages, the thermostat would come on with a click, but the heater would not. I discovered that stomping once or twice on the floor by the heater would cause it to engage. I contacted the property managers and explained the situation and they sent the repair man out, who replaced the thermopile after briefly investigating the heater.

When he left I felt fine about this situation and expected no more problems. But, within 24 hours the pilot went out again, and subsequently began to go out within 12 to 16 hours ever since.

I contacted the property manager again and told them about the situation, and the repair man was sent out again. He decided to order a new gas valve, and after about three weeks of relighting the pilot now every 8 to 12 hours, it arrived and he came out and replaced the gas valve.

When he left I felt all assured that there would be no problems. But within 12 hours the pilot went out again. With the old gas valve, I knew the pilot was out only when it began to get cold. But with the new gas valve the behavior was different. Now the heater started up, ran for about a minute, then shut off with the pilot gone out. Always after about 8 to 12 hours of running normally.

I assume there's no need to express the profundity of my frustration nor the depths of my dismay at this point. The repair man even suggested I might be making this up. But, I'm not. When the pilot went out after the second gas valve was replaced, I began to log the times at which the pilot had to be relit. Still, I at least no longer had to stomp on the floor to start the heater when the thermostat engaged.

After a week and a half of logging outages twice to three times daily, many times noticed at the moment the pilot went out in the manner I described two paragraphs ago, I decided to see if the original thermopile had been replaced with a faulty one. I sought one out and purchased it for just under $40 and installed it. Very easy to install.

Within 12 hours the pilot went out again. I contacted the repair man (talking with him directly now) the next day and told him all about it. We decided that since the gas valve had been replaced and the thermopile had been replaced twice, the only thing left to replace was the thermostat--though he made it clear that he didn't see how this could possibly be the cause.

He came out the next day and replaced the old thermostat with a known good one from another unit. If it was a known good one, I have no idea under what circumstances it operated, because with this dysfunctional wall heater it barely worked. For the first few days I regularly had to thump the wall the thermostat is on in order to get the heater to turn on--a few degrees cooler and several minutes after hearing the thermostat click a closed connection. The pilot still went out every 8 to 14 hours. And not only this, but with the second gas valve and thermostat together, when the thermostat kicked in, the heater would often turn on for a minute, turn off, turn back on, turn off again, turn on for three minutes, turn off for four, turn back on again, and carry on in this manner for 20 to 30 minutes before deciding to either stay on (if all this didn't warm the house) or off (if all this did warm the house)--or go out altogether (if the magic 8 to 14 hour period was up).

There's another behavior to report that has been persistent through all this. If I leave the house for any length of time, with the thermostat off, when I come back, days or weeks later, the pilot is still lit. It is only after the thermostat has been turned up to keep the house warm and the heater has been starting and stopping over the course about 8 to 14 hours that the heater shuts off with the pilot gone out.

I managed to discover that if I slide a piece of paper behind the dial of the thermostat, which causes the dial to be pushed forward a little, the thermostat behaved more normally. However, the pilot still goes out every 8 to 14 hours of use, without fail, and I still occasionally had to thump the wall the thermostat is on in order to start the heater.

At this point, the repair man called in someone who repairs heaters for a living, and yesterday he came. He went over my outage log, did some checks, and proclaimed that he doesn't understand how the pilot could be going out all this time through two thermopiles, one gas valve, and one thermostat. He thought maybe it was a draft, but when I asked him if a draft could blow the heater out when it was on and warming the house for a minute, he said no, there's no way that could happen. I then explained to him that within the 8 to 14 hour period between outages, the wind could be raging outside without so much as causing the pilot to flicker. It's not a draft.

So this second repair man decided he'd start the heater off with a clean slate, and he replaced both the gas valve and thermopile there on the spot. When he left, the heater was running without the whole on-off-on-off business and I managed to let myself have a good feeling about it.

But about 40 minutes ago, a good 15 or so hours after the third gas valve and forth thermopile were installed, the pilot went out again--with an audible *click* heard from the other room.

I'm at my wit's end. Can someone give me any idea just what on god's green earth is going on with this heater? Has anyone ever heard of something like this before?

I am seething desperate for a solution. I'm afraid to call the property managers at this point because I'm sure they'll think I'm making this up. I need help and I need it bad.

Any assistance would be more than appreciated.

-----Erin


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Supplemental info: There is no "limiter switch" on this heater. The wiring consists of the thermopile to the gas valve and the gas valve to the thermostat--that's it. All three gas valves have been wired exactly the same.

Yoyizit 12-10-2009 10:51 AM

Post a schematic if you have one. These kinds of problems have something to teach.

wornways 12-10-2009 11:27 AM

Quote:

Originally Posted by Yoyizit (Post 364513)
Post a schematic if you have one. These kinds of problems have something to teach.

Hi Yoyizit,

I would love to post a schematic. But I don't know if I have one. Is it something that would be on or in the heater itself somewhere? I can also take detailed pictures of the heater and the thermostat and post them if this would be useful to you and other readers.

Thanks, and take care,

-----Erin

kennzz05 12-10-2009 09:26 PM

has anyone cleaned the pilot oriface if the pilot flame isnt strong enough the burning flame will cause increased draft thru the heat exchanger and pull the pilot away from the tpile and cause it to go out my vote is on cleaning the pilot and verifying a good strong flame that totally engulfs the thermopile

wornways 12-10-2009 09:52 PM

Quote:

Originally Posted by kennzz05 (Post 364792)
has anyone cleaned the pilot oriface if the pilot flame isnt strong enough the burning flame will cause increased draft thru the heat exchanger and pull the pilot away from the tpile and cause it to go out my vote is on cleaning the pilot and verifying a good strong flame that totally engulfs the thermopile

Hi Ken,

All check. Throughout the whole ordeal described in my original post, the pilot flame has always been very strong and has always engulfed the thermopile without so much as a flicker.

In fact, the second repair man gave the heater a thorough checking over. He said the pilot assembly was very clean, but he removed just a small bit of carbon that had collected inside anyway.

I have one more piece of new information to add. With the original gas valve I often had to stomp on the floor or thump the wall next to the heater in order to get it to turn on once the thermostat engaged. With the second gas valve this was no longer the case. However I just discovered with this third gas valve, installed only yesterday, that I once again have to stomp on the floor or thump the wall next to the heater in order to get it to turn on once the thermostat has engaged. So, it looks like I'm back to the same behavior that was occurring with the original gas valve.

Later tonight I'll take pictures of the heater, the thermostat, the pilot flame, the active burner, and the gas valve, anything I can, and post them here. Maybe someone will see some clue in the photos.

It's been about 14 hours since I last lit the pilot, so we're getting near time for another outage.

kennzz05 12-10-2009 10:00 PM

the stomping/hitting the wall thing could be a broken tstat wire or nearly broken id try just for giggles running a piece of wire outside of the wall and put the stat on a table or something just to see if it makes any differance

beenthere 12-11-2009 05:43 AM

You may have already done this. But if you haven't.

Physically trace the thermostat wire back to the gas valve. There may be a limit switch that you are unaware of.

I say this because you said you sometimes have to stomp near the furnace to get it to turn on.

Next. On units with a bad limit(same can happen with no limit). They tend to over heat causing too much draft. And at the end of the cycle when they turn off. The excess draft can draw the flame too far off pilot and cause it to go out.

Pics will help.

wornways 12-12-2009 01:43 AM

Quote:

Originally Posted by beenthere (Post 364879)
Physically trace the thermostat wire back to the gas valve. There may be a limit switch that you are unaware of.

Next. On units with a bad limit(same can happen with no limit). They tend to over heat causing too much draft. And at the end of the cycle when they turn off. The excess draft can draw the flame too far off pilot and cause it to go out.

Pics will help.

Hi beenthere,

Appreciate your input. Thank you. Here's what I know in relation:

If there is a limit switch anywhere, it would have to be inside the wall next to or behind the heater. I can only trace the wire about four inches back and up and then it's gone. Both repairmen who have been here to deal with this heater have commented on the lack of a limiter switch. So I'm feeling pretty sure there isn't one. Still, have you ever heard of cases where limiter switches were installed inside the wall near or behind the heater?

I have observed the pilot going out about a minute after the heater has been on and just before it would normally turn on. It's possible that the pilot has gone out at the end of the heat cycle, but I don't think so because I've developed a habit of checking the pilot, and when it's not out, it's usually on between cycles, and out just before or during a heat cycle. Still, this is worth my bearing in mind. So I'll watch for it.


Quote:

Originally Posted by kennzz05 (Post 364815)
the stomping/hitting the wall thing could be a broken tstat wire or nearly broken id try just for giggles running a piece of wire outside of the wall and put the stat on a table or something just to see if it makes any differance

Hi Ken,

This struck me as a good idea. Since the old thermostat is still around that was replaced with the other old thermostat from another unit, I've dug through my things for some wire and I've hooked up the old thermostat to the heater. It's sitting about three feet away on the other side of a wall from the heater. That might sound impossible, but the heater is just next to a door frame.

Before I post the pictures I took before, I'll see how long it takes the pilot to go out using this configuration.

What's interesting is that when I took pictures of the gas valve, I pinched the thermostat wire to the side in order to give me a clear shot of the label on top of the gas valve. The heater then went for another 28 hours without the pilot going out. Altogether the pilot stayed lit for just over 40 hours, which is the longest it's stayed lit in over two months. I have to wonder if pinching the wire did anything. Later when the heater didn't turn on, stomping on the floor or thumping the wall by the heater had no effect. However, when I thumped the wall by the thermostat, then it went on. How strange is that? Is it possible the thermostat wire is cracked in more than one location? It seems to be every bit as old as this house, and let me tell you something--I think this house has been here since about when our city of Ukiah, CA was founded.

Will report back again next time the pilot goes out. If it doesn't go out in the next few days, then I'll report back with that information and contact the repairman with the info. I'd love for there to actually be a solution.

But, tell me, do you think it's possible for a cracked thermostat wire to somehow cause the pilot to go out? If so, would it have something to do with static electric build-up along or near the wire and a strong enough discharge that could cause the gas valve to close all valves, including the pilot?

Livewire78 12-12-2009 02:12 AM

I've seen this happen before and this is gonna sound crazy but, its possible that the thermopile is not close enough to the pilot flame, the metal support they rest on may be thin enough that you can hand bend the thermopile a little closer to the flame. Like I said seen it happen before, just a little closer may make all the difference. Its worth a shot. I've learned that sometimes its the simpliest things that everyone oversights

log_doc_rob 12-12-2009 09:51 AM

If you have a multi-meter, check the voltage of the thermopile with the main burners on and off, these readings will be different and report back. I would think there is a problem with the pilot not properly heating the thermopile due to pilot being too small or pilot being improperly adjusted so it is not heating the tip of the thermopile.

wornways 12-15-2009 12:42 AM

Quote:

Originally Posted by Livewire78 (Post 365352)
I've seen this happen before and this is gonna sound crazy but, its possible that the thermopile is not close enough to the pilot flame, the metal support they rest on may be thin enough that you can hand bend the thermopile a little closer to the flame. Like I said seen it happen before, just a little closer may make all the difference. Its worth a shot. I've learned that sometimes its the simpliest things that everyone oversights

Hi Livewire,

This is a good call, but I and the repairmen have already tried about every permutation of moving the thermopile closer to or farther from the pilot and increasing or decreasing the strength of the pilot flame. In every case, the thermopile has been completely surrounded by a sturdy flame and the tip covered by the flame.

Quote:

Originally Posted by log_doc_rob (Post 365472)
If you have a multi-meter, check the voltage of the thermopile with the main burners on and off, these readings will be different and report back. I would think there is a problem with the pilot not properly heating the thermopile due to pilot being too small or pilot being improperly adjusted so it is not heating the tip of the thermopile.

Hi Doc Rob,

I have a multi-meter, and I've tested the voltage from thermopile. With the heater off I get about 350mv. With the heater on I get about 400mv.

I think I've solved the problem, however. I'm about to post a follow-up.

wornways 12-15-2009 01:25 AM

Hi again Ken,

Your suggestion seems to have paid off. As of about now (11pm PST), the pilot has not gone out in 72 hours. This seems like a miracle to me after everything I've been through with this heater.

There's more. The entire time I've lived here, the heater would take a very long time to warm the house, especially when it was below freezing outside. But since hooking up the old thermostat using wiring known to be good (power cord to an old laptop I no longer have), the heater has warmed the house quickly and kicked in and shut off predictably. For the first time since I've lived here, the heater maintains the house at temperatures within a 3F margin, whereas before (within that 8 to 14 hour period between outages) the margin was somewhere inside 12F. So this all by itself is a significant improvement.

Not once in the last three days has it been necessary to stomp the floor by the heater, thump the wall, rattle the thermostat, or any such behavior in order to get the heater to turn on. The heater now comes on right when the thermostat kicks in, and shuts right off right when the thermostat disengages. There has also been none of that on-off-on-off-on-off behavior I previously described.

Far as I can tell, thanks to your insight, we've found the problem. Somehow the wiring to the wall thermostat has gone bad in such a way (and I'm guessing here) as to periodically cause the current from the thermopile to run to ground, effectively breaking the current to the electromagnetic pilot valve for a moment--which was a moment too long. Perhaps this also caused an irregular flow of current over all, causing the heater to portray some of that ghostly behavior I described in my original post.

I feel less haunted now. I'm still a bit pessimistic and wonder if the heater will start going out again any time, but for the moment I'm at least feeling less haunted in general, a bit more relaxed in my own home.

I called the property managers today and told them about my amazing discovery, and we agreed to touch bases again on Wednesday if the pilot stayed lit without problem. If so, then they plan to rewire the thermostat with brand spanking new wiring. I also talked to the repairmen, and somehow their both a bit shocked and embarrassed and yet relieved and curious.

If anyone can offer an explanation of how less than perfect wiring between the thermostat and the gas valve could cause the heater and pilot to go out every 8 to 14 hours, please do tell. I'm very interested in knowing more.

I can't thank you enough, Ken. In fact, let me thank everyone who offered their insights. Without them I might well never have solved this colossal headache, still cold and temperature-mental. I'll report back in a few days with an update. Hopefully it will be good news.

wornways 12-20-2009 10:58 AM

Hi Folks,

I'm still wondering if anyone can explain how "bad" or old thermostat wiring could cause the pilot to go out every 8 to 16 hours. When tested, the conductivity was measured at between 350 and 550mv, depending on the thermopile that was in there (we went through four of them don't forget). The repairman for the property managers came out on Thursday and rewired the thermostat to another room. There hasn't been any problems since, and the house keeps warm.

When he saw what I did with the thermostat sitting on the floor on the other side of the wall from the heater, and thought about what I told him on the phone about how there hasn't been any outages since I temporarily rewired the thermostat, he told me that he's talked with a few HVAC people he knows about my whole heater problem and this solution I came upon, and he said that none of them had ever heard of bad or old thermostat wiring causing the pilot to go out once or twice a day. In their experience, when thermostat wiring for a millivolt gas heater is bad in any way, the heater either won't turn on at all when the thermostat is engaged, or the pilot won't stay lit at all. In their experience there has never been any sort of intermittent behavior with regard to the pilot when thermostat wiring was bad or old.

So, if anyone could offer a reasonable explanation, I'd love to hear it. I'll also print this thread up and give a copy to the repairman.

log_doc_rob 12-20-2009 11:29 AM

I have seen issues with a screw or nail that has punctured the 'stat wire and grounds it occasionally. I have also seen where the crimp connector has not been tightly crimped or it has been crimped partially on the wire insulation which would cause temporary main burner outages, but not pilot outages.

There may be a spill or high temp. switch wired somewhere in line with the 'stat wire and you bypassed it when you rewired the 'stat. Make sure that you have a good carbon monoxide detector and good life insurance....just in case there is a safety sensor doing it's job causing the pilot outages.

wornways 12-20-2009 12:03 PM

Hi Doc Rob,

I just went ahead and tried to remove the old thermostat wire to see what happened. It's definitely hanging on to something. I tried from both ends. At the wall end it comes out about 8 feet and then gets stuck. Feels like there's a knot in the wiring from that end. At the heater end, there is no give whatsoever, and there's a metallic *clink* sound about a foot high along the heater and some inches deep whenever I tug on it, which makes me think it's hooked up to something. Does that sound like a possible spill/temp switch?

Are carbon monoxide sensors sold that operate on battery and stick to the wall or ceiling much like a smoke detector? If so I think I'll swing by the hardware store today and grab one. If I can find one, where should I put it? Near the base of the heater? I'm new at this sort of stuff.

I'll also report your thoughts to the repairman and see what he says. It always struck me as a bit strange that he never pulled the heater out of the wall to double-check for any components that might be installed along the thermostat wiring. Based on your thoughts, I think I shouldn't write this off as solved just yet.


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