Old furnace control/ relighting

[Eric in Ohio]

Hopefully, this is appropriate and in the correct forum.

I own a duplex and one of the units is heated by an older furnace. The unit is currently unoccupied, but I received a gas bill for 200+. That is with the thermostat set at less than 50 F, and the hot water heater set to vacation.

While I was in the basement reading the gas meter to assure the correct reading, I heard the furnace come on. Thinking that this furnace was coming on frequently due to maybe a faulty thermostat, I decided to shut it off completely.

The gas controls were not like the furnaces of the last 10 years or so with the clearly marked dial of ON/PILOT/OFF. The controls appear to be a 4" rectangular metal box with a red knob (I believe) with a molded area to turn it. There are no words on it to show me what orientation is for pilot off and such. The the gas line goes to another box with set screws for wires. Then up to the pilot. So not wanting to do the wrong thing, I decided to just turn the gas to the furnace completely with the valve from the branch line.

So this question would be for a pro with some experience with older control modules. Problem is that when I will want to relight it, how will I go about this?

PS, I am not ignorant of how to light pilots, have done it many times. I've just never seen a control like this. So I decided to err on the side of safety.

Thanks for any responses

Eric in Ohio

[Wirenut]

Eric
The furnace you describe sure sounds like an old beast. If the pilot safety is separate from the gas valve you might have a old unit with a WILD pilot, that is the gas is NOT 100% shut off. There should be printed instructions somewhere on the furnace with relighting instructions but as you said err on the side of safety, I would have the unit inspected before it is returned to service.

[Eric in Ohio]

the gas is not 100% shut off right now?

Keep in mind, the valve I closed is part of the gas piping, not part of the furnace.

Please confirm.

Thanks

[4l530]

Is the pilot out? Some of the ancient furnaces had a separate shut off for the pilot gas called a 'B valve' on the side of the gas cock.

The controls you describe do sound old. I bet the pilot in there is the $ize of my thumb. Maybe there'$ more than one pilot in there even. No wonder it co$t$ so much with all this ga$ being wa$ted.
Maybe you $hould replace it. You can't afford to keep that $ucker around any longer.

[lolson]

when was the last time you your filters? and are they accually clean (dont go by the last time you changed them). this will increase your bill.

im not a person that will tell you you need a new furnace but a gas hog is a gas hog and a upgrade may save you $$$$ in the long run.

[Eric in Ohio]

Ok guys, I just came back from the cold walk from the duplex.

1. It is a Kleen-Air GL 125
2. Yes the pilot IS on to my suprise, and it does have the A and B valves you described. (means I don't need to relight it, it was never off)
3. Filter last changed last heating season which was the last time it was occupied.
4. I agree, it could use replacing, but as heartless as this may sound, when occupied by renters, they are the ones paying for the gas. And right now, a new furnace is very cost prohibitive. Since I have now closed that A valve, then the pilot will be the only thing coming on. Now it should function just like the water heater on vacation setting, (pilot only)

Just read the meter and it was exactly the same ccf reading as it was yesterday. $$$problem solved.

I actually went over there yesterday to read the meter after the sticker shock of my gas bill and then shut the gas off. It makes me sick that I didn't turn off the A valve when the last renters moved out costing me 216.00 for heat I didn't keep warm with.

The actual problem that I may need help with now is that is my suspicion of a malfunctioning thermostat the reason that it came on repeatedly even when it was comfortable inside and the thermostat was set on 50?

I am probably going to replace it with a simple programable one like the one I installed in my own home. Very effective and properly functioning for about 40 bucks from Home depot, (honeywell)

[oldertech]

I hope you don't live in a cold climate. You might need some heat to prevent water pipe freezing. I guess if that could be a problem you would have thought about that.

Some old furnaces had what looks like a pilot safety. Red button, thermocouple. In reality the safety didn't shut off the pilot and main gas, rather only the main gas.

If there are not lighting instructions try this.
When you go to relight the pilot, open it's valve, lite, let it heat up a minute, push the red button. Test it by turning the stat on.

The stat you describe is a honeywell t87f. They have a mercury bulb inside that switches the heat on and off. Tilted one way it goes on, tilted the other way it goes off. The balance point should be within a few degrees of the present room temperature as measured at the tstat.

[oldertech]

Oh, I see your name says Ohio.

Maybe you should ask friends, an hvac contractor or plumber where you need to set the tstat to prevent pipe freezing.

Or maybe you have heat tape on your water pipes.

I'm in so. cal. so my experience in this area is zero.

[firecontrol]

When you said you heard the furnace come on while there... did you hear the blower come on and was it blowing a reasonable amount of air out of the registers?
If the blower stops blowing air for whatever reason the unit will still cycle off and on, usually on limit, and will waste lots of gas.

[oldertech]

Why is it that the older you get you find it easier to learn the new things, but harder to forget the misinformation that you've picked up?


:D

[hetrola]

If you have an older stat like was mentioned above with a mercury bulb, make sure it is level.
In rentals if you take the stat off to paint and it gets put back on crooked it could be off 5 degrees or more.
If it is the round t87. pull the outer face plate off and level across the top.

[Eric in Ohio]

Thanks, I have never upset the stat, but my last renters may have, so I will check that level. If not, I will change as stated earlier to the programmable. I believe that they are more accurate anyway, and the programmable features go along way in saving $

The blower comes on shortly after the main burner has lit. It's like the olympic flame :D

I will check the registers for airflow since by occupation I am a home energy rater and have my own flow pan and pressure pan.

[klyons20]

set t stat to lowest setting . you only want to keep it above freezing.


regards,
Kelvin

[hetrola]

Thanks, I have never upset the stat, but my last renters may have, so I will check that level. If not, I will change as stated earlier to the programmable. I believe that they are more accurate anyway, and the programmable features go along way in saving $

The blower comes on shortly after the main burner has lit. It's like the olympic flame :D

I will check the registers for airflow since by occupation I am a home energy rater and have my own flow pan and pressure pan.

How does your duplex rate for energy efficiency?:eek:

[Eric in Ohio]

1. lyons20-I did have the thermostat set to the lowest setting, but it was still coming on, so I had to cut the gas by closing that A valve.

2. I have never ran the blower door test on the duplex, but if it tells you anything, it's about 100 years old with wood siding, (no sheathing underneath), and a bunch of the retrofit insulation plugs all around. Let's just say, that when we lived there we did NOT keep it warm out of fear of the bill.