Gravity fed furnace no safety

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  #1  
Old 10-29-18, 07:07 AM
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Gravity fed furnace no safety

I have a 1921 Toridaire gravity fed furnace. It runs great, no issues except if the pilot blows out the valve will still open if the thermostat is turned on. There is a small copper tube that runs from the valve into the gas chamber but is just open at the end. Is that a thermocouple? This tube is not shown in the pics as I removed it. I plan to replace the system next year, but got to get through one more winter.... ok just to be clear I live in Oakland ca so lowest temp is low 40s!!

Is there a safety shutoff on these monsters?

Pic of valve
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Last edited by PJmax; 10-29-18 at 11:31 AM. Reason: added pic from link
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  #2  
Old 10-29-18, 10:24 AM
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Those old setups don't shut gas to the pilot when the pilot goes out, but there is a safety that stops the main valve from opening if the pilot goes out.

Since you're planning on replacing it, just leave it alone.

It shouldn't be going out unless the pilot orifice is dirty, in which case, have the pilot orifice cleaned.

You'll probably need new ductwork and vents suitable for forced air when replacing.

I urge you to do everything you can to reduce the heat loss of the house prior to replacing, even if you have to postpone getting a new heating system. New system is sized for the house, it's bad to do the system first and upgrade the house later.
 
  #3  
Old 10-29-18, 01:13 PM
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To @ Mduresmith; you wrote,"It runs great, no issues except if the pilot blows out the valve will still open if the thermostat is turned on". If you are talking about the gas valve for the heat and not the valve for the pilot, then this is a very dangerous situation. I would not wait till next year to fix this problem. Not to scare you but if the pilot were to go out and the main gas valve stayed open the furnace would fill with gas and probably explode causing a disaster , burns, or even death to anyone in the home.
 
  #4  
Old 11-05-18, 06:49 AM
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Usef10, the main does operate when the pilot is out. This my main concern. What is that mechanism?can it be fixed? Is it supposed to have a thermocouple? How do I get a replacement. I also fully agree that the new system is post wall and floor insulation. I’m thinking of going with a electric heat pump with radiant heating, but that’s next year and I haven’t priced it out yet......

Steamboy, I assume I’ll have to replace the main valve? If so how do I figure out what to replace it with? I can’t find any reference to the existing valve or a replacement. I’m stuck. I hate to waste the money for one season, but safety has to come first.

Thank you,
Mark
 
  #5  
Old 11-05-18, 09:29 AM
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This is a very dangerous situation and the gas should be shut off until this is fixed.

It's possible yours has a pilot safety switch rather than thermocouple or power pile that's stuck.

No expert on these things - but pictures of the rest of the controls would help.

Really this system should be replaced sooner than later. You'll probably need new air ducts too.
 
  #6  
Old 11-05-18, 02:06 PM
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I thought that was a millivolt valve. That means without a pilot it can't open.
More info is on the top of the valve where wired.

You may need to upgrade now..... as you might not be here next year.
 
  #7  
Old 11-06-18, 08:23 PM
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I agree that I need to replace the valve, but I can’t figure what valve to replace it with. How do I figure out the spec’s of the valve I need?
 
  #8  
Old 11-07-18, 04:43 AM
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The gas valve in the picture looks like an old B-50 General Controls gas valve. The tube you removed was the vent tubing that vented gas from above a diaphram allowing the valve to open. Geeze, I am showing my age. You should post a picture of the pilot assembly so it can be identified. However, many , many years ago, the company " White Rodgers" made a safety pilot that had an internal switch actuated by a bi-metal device. They were discontinued since it took 30-60 seconds for the switch to open with the loss of flame and would also fail closed causing a safety issue. You may have one of these. Gravity furnaces fell out of favor due to their inefficiency. Most of the duct work in the basement had to be round for the heat to move. Many of these furnaces were later equipped with blowers to help move the air. Wow, I haven't seen one of these in forever. Hope this is useful information. List the model number of the gas valve and poat a picture of the pilot. The gas valve may be OK or not, and if you have a "safety pilot" as they were called a replacement may be needed. numbers and pictures are required.
 

Last edited by Steamboy; 11-07-18 at 04:47 AM. Reason: more info
  #9  
Old 11-08-18, 10:05 PM
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Yes you right! I found the markings, they were on the backside of the valve, next to the heater. I had to slide a phone camera down behind the valve, take a pic and then read it. It’s a ITT General Controls B50 valve. B50LC84 I think stamp saying J4H.

What at can I rep,ace this with?
 
  #10  
Old 11-09-18, 04:23 AM
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More information is needed on the controls of the furnace and exactly just what safety controls are presently installed. As I said in my last post, a picture of the pilot assembly is needed and a picture or drawing of the wiring schematic would help. Replacing the gas valve may not be necessary if the problem is not the valve. If the pilot safety is not working properly, that is your biggest concern. You need to find out what control or controls are allowing the gas valve to be powered when it is not supposed to be powered. A furnace like yours has a pilot safety of some type, a gas valve and gas pressure regulator, air temperature operating and limit controls, a thermostat, etc. Please get back with the info needed. Nobody will say to just replace the gas valve an the problem that you describe is fixed. Once we know just what is the source of the problem, someone like " SPOTT" who monitors this site should be able to help better than me with installing modern and up to date equipment.
 
  #11  
Old 11-09-18, 07:06 AM
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Does this image show up?
https://drive.google.com/open?id=1Pm...QvhCK1qnfy7O-N
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Last edited by PJmax; 11-11-18 at 12:57 PM. Reason: added pic from link
  #12  
Old 11-09-18, 07:35 AM
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Gravity fed furnace pilot

Ok, I think this attached a pic of the pilot
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this is the top of the valve -24 volt control. One set of wires to thermostat, the other to a transformer.
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  #13  
Old 11-09-18, 08:16 AM
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You need some type of safety pilot to make this furnace safe. You may want to wait until one of the younger experts make recommendations. Their recommendations may respond instantly making their fix safer than mine. My fix would include parts that I used many years ago. while making the furnace safe, they take more time to respond to a pilot outage. They are simple and easy to install and you can purchase from a company like "supplyhouse.com" or other parts company. An example would be to install a simple BASO control L62AA-5 plus a new pilot and thermocouple . The switch would be wired in series with the gas valve. Loss of the pilot flame would open the BASO switch and shut off the gas valve.
 
  #14  
Old 11-09-18, 09:56 PM
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Steamboy, thank you so much, this was the simple solution I was hoping for. Iíve ordered the parts and will let you know how it goes.

Mark
 
  #15  
Old 11-10-18, 07:28 PM
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Are you sure the valve is a B-50 and not a B-60 ? The pilot type is difficult to determine. Is there a transformer supplying voltage? If it is a B-60 you just need to replace the bleed tube that is missing from the valve.

Never mind I just saw 24 volts on top of the valve
 
  #16  
Old 11-11-18, 08:52 AM
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Hereís the photo I took on the backside of the valve with my phone.
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