Old floor furnace won't start without a tap on the gas regulator

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Old 12-14-17, 11:22 AM
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Old floor furnace won't start without a tap on the gas regulator

Hello, I have an old floor heater (90+ years), though the valve and regulator are newer (10+ years, though the wire connections used slotted screw heads). The heater was not working, but the pilot was lit, so I replaced the thermostat batteries, then replaced the thermocouple since it had a bunch of crud on it. When that didn't work a friend suggested I tap the regulator with a wrench and the heater turned on instantly.

I was wondering what exactly was happening when I tap that regulator, and if it's just a short term fix. Also, if it's really the regulator or the gas valve that is being affected when I tap it. I did notice the heat did not come on last night, so I tapped it again and it worked fine. Anyone know how often these guys need to be replaced? I've included some pics of the regulator and valve.

Thanks so much for your feedback.
 
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Old 12-14-17, 12:10 PM
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I would doubt it's the regulator.... more likely the gas valve but I'd recommend changing them both if you want to keep that antique running. It is also very possible that the pilot generator is not generating enough voltage to open the valve cleanly.

I'd recommend professional installation of the parts so that the heat exchanger or flue can be checked. I'm a little leery of those very old units as they can get rust thru issues and they have a very limited safety system.

We don't see all the gas piping but a drop leg before the regulator is a good idea. It's like a tee with a nipple pointing down. Any crap or moisture drops into the nipple.
 
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Old 12-14-17, 04:47 PM
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The whole thing should have been replaced 50 years ago.
 
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Old 12-14-17, 06:02 PM
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There is something screwball in that the first picture shows what appears to be the connector for a standard 30 millivolt thermocouple on the upper left side of the gas valve. There also seems to be a cable from a 750 millivolt thermopile generator. I do not understand why the thermopile cable is knotted around the gas piping in that manner.

Also, the wiring and terminals in a 750 millivolt system must be scrupulously clean and tight. I would suggest removing the terminal screws and cleaning both wires and terminals with some fine sandpaper. Make sure that you replace the red and white wires on the same terminals.
 
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Old 12-14-17, 06:18 PM
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My thought was thermocouple for the pilot and pilot generator (thermopile) to run the gas valve.
 
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Old 12-14-17, 11:41 PM
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The pilot burner is supplied from a "B" valve mounted to the main gas valve body. It is in the inlet portion of the main gas valve body and it is doubtful if it is "supervised", meaning if the pilot were to go out the gas for it would continue to flow. This was common years ago.

BUT, I could be wrong. I've seen a lot of old installations, some with supervised pilots, most without. In those installations where the pilot was supervised I saw an additional safety switch/valve called a pilotstat. It is possible that this has a supervised pilot, I would need to see a whole lot more than is shown in the posted pictures to make that call.
 
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Old 12-15-17, 12:24 AM
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Hi, I appreciate all the feedback. I have had the heater inspected, both by the local utility when I bought the house and a few years ago when I was having similar trouble. Back then I was not able to be present for the fix, but PG&E did confirm that the pilot is operating correctly and safely, or at least it was in 2009.

I will definitely clean things up and see if that improves performance. That's a really good suggestion. I think the knotting is because the heater is overhead in a stairwell to the basement, and a previous owner did that to get it out of the way (lots of other work in the house is like that).

I've attached a few more pics from further away, so you can get an idea of my setup. Would it just be prudent of me to replace both the valve and the regulator and clean up the wiring?
 
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Old 12-15-17, 12:27 AM
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Sorry some of the pics flipped while posting. I tried to correct the "up" view but I guess it didn't work.
 
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Old 12-15-17, 02:30 AM
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Joe Caption gave you the best advice, replace the entire thing.

I see yet another "thing" that I am not familiar with, the device between the gas valve and the burner venturi, located just at the edge of the galvanized sheet metal. It appears to have two connections of the pilot gas piping.

If replacement is simply out of the question I would think about a spark-ignited retrofit valve. Such, if they are still available, would replace the valve with a double electric valve and spark ignition module. It would give both pilot and main flame supervision as well as 100% lock off of the gas. It, however, require an additional 24 volt power supply. If it is necessary to operate without any external power then maybe a separate pilotstat (safety device on the constantly burning pilot flame) and then a new 750 millivolt gas valve. There are other options as well.

Note well that your fire insurance may not accept any stop-gap, or in my terms, half-a**ed "fixes" just to get it going. Try cleaning all the wire connections first. Then measure the voltage between the red and white wires, ideally close to 750 millivolts or 3/4 of a volt. If the voltage is significantly lower then look at the pilot. It should be a fairly large and bushy blue flame fully engulfing the thermopile generator. If it isn't then clean the pilot burner orifice. If the pilot looks good then change the thermopile. Understand that this part alone is probably $40 or more. If the voltage is sufficient then it is a problem with the gas valve itself and it will probably need replacement. Biggest problem here is that I doubt you will find anything close to an exact replacement and therefore a lot of re-piping will be in order.
 
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Old 12-16-17, 08:52 PM
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The thermocouple you see is actually the bleed tube. Tapping the gas valve is an assist to help it open, meaning probably the voltage is low or the bleed tube is partially plugged. Try removing all the connections at the B-60 valve and clean them. I didnít see a picture of the pilot, so I canít tell if it is clean and what voltage it is. Do you know if you have a millivolt style thermostat? As far as the pg wire wrapped around the gas line, Iíve seen many like that with no Iíll affects. I just took another look and found the pilot is a PG-1 which is quite old and I could see some luminous flames. PG-1 was a 320 millivolt style and if the pilot is dirty or the wrong thermostat is used they tend to have trouble opening the valve.
 
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Old 12-16-17, 09:54 PM
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Hello, mbk3, thanks for answering my question about the tapping fix. I have attached a pic of the pilot, though I have not been able to get up to get a meter reading yet. The heater is over a flight of stairs and I'm going to have to build a platform or get some stair risers to put in a ladder to get up and work at the top of the unit.

The pilot works very well, the flame is bright and It completely engulfs the thermocouple. When I pull the thermocouple out nothing I do will get the heater to turn on, but it pops back on once the thermocouple is in place and I have tapped the gas regulator. My thermostat is a Honeywell rth2308 running off of 2 AA batteries, so it probably is a millivolt system, but the wiring follows the most tortured route through the walls, around pipes, and god knows where else, so the voltage may not be all that clean.
 
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Old 12-17-17, 08:06 AM
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Thanks for the great pictures. At this point using a meter will tell us where the problem may be. Might be multiple problems, but once you get a meter on it we can provide a fix Iím sure.
 
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Old 12-17-17, 08:16 AM
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Now I see the thermocouple you replaced. It appears you installed it in the vent line opening of the gas valve. Please remove and replace the tubing you took out. The valve wonít open if the vent is plugged or at best be slow.
 

Last edited by mbk3; 12-17-17 at 08:18 AM. Reason: Correction
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