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Old 11-08-2011, 07:38 PM   #31
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Is this old Furnace Able to be Serviced?


Flame spillage can easily be tested out with a source of smoke just an inch above the burners on the line between the inside and the outside of the furnace. A cigarette will do it. When the burners initially light you will get an ignition that might push some excess fumes out of the burner opening area but only for a second or two. This will discolor the area outside of an older furnace above the burners over time. After that, the air in the room should reverse and be flowing into the burner chamber, through the furnace and up the chimney. If you hold a something that produces consistant smoke (cigarette or incense) right at the opening above the burners you will see if spillage (What you don't want) is pushing the smoke away from that opening or if the correct direction of air (smoke)is being pulled into the burner chamber. You can even hold a lit lighter just above the burners and beside the furnace body and if you have spillage, it will put out the lighter flame. Eventually just holding your hand along there will tell you if there is a problem or not. Spillage will produce moist hot air out of the burner chamber whereas a correct direction of air will not.

If it passes your test, do it all again with all the house windows & doors closed and the clothes dryer on. This will create a low pressure area within the house that will most likely produce spillage if your house has insufficient fresh air coming in to counter it.
If it passes this test then, then your unit is not spilling.

Let us know what the result is. This test only indicates spillage and not a cracked exchanger.


Last edited by how; 11-08-2011 at 07:42 PM.
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Old 11-09-2011, 01:45 AM   #32
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Is this old Furnace Able to be Serviced?


Quote:
Originally Posted by yuri View Post
Visual signs like that are HUGE red flags and it depends on the homeowner whether he wants to see them or not.
I will admit that I don't think that CO is spilling out of the furnace based on the fact that I have so many CO monitors all around my home and even in the last couple of days since talking with you guys I installed 2 more in the basement right on the furnace. See the new photos below for reference.
I bought 10 of these little detectors from a local fire alarm device distributor awhile back. I put seven in the house and had 3 left over so I just mounted these around the furnace and I have not even got a "blip" of CO detection. I do of course remember what you said a few days ago about these $50 dollar units not being too good at detecting low levels.

It doesn't take an expert to know that an old furnace like this could be very dangerous. It is probably the most potentially dangerous part of this old house that I live in.

I do however completely respect the opinions of the experts here at the forum that is why I've decided to buy the commercial unit and the 50PPM calibration gas that will be delivered tomorrow I hope.
Besides colorless, odorless, toxic gases have no friends and if there is a serious problem, I'm not going to be the fool who ignored the advice of experts because I didn't want to see the red flags.

Quote:
Originally Posted by Marty S. View Post
There's also a 200ppm limit of CO in the flue gas even if it's not dumping into the house. Soot in the exchanger results in CO levels many times that. Perhaps your new meter can test that too. It might ruin it in seconds though so read the directions.

The reason most have not got into the fan issue is we,as techs in the field, make sure the furnace is safe before moving on to any other issues. The same concern is carried over with our advice on this forum. Step one is ALWAYS peoples safety.
Thanks Marty. The monitor that I've purchased has a range from 0-500PPM so It can handle a 200PPM hit with no problem. I could run into trouble if It was exposed to a super high concentration of something like 10,000PPM for a long period. If that were to happen, I could purchase a new cell for around $150 I think. I guess I'll have to climb up on the roof and measure the output of the stack. I hate climbing up on that tile roof because its hard to walk on and I don't want to break a tile with the rains coming this weekend. Thanks guys, VC

CO Monitor Mounted Above the Furnace


Close Up of the CO Monitor


CO Monitor on the Side Between the Furnace and Exhaust Chimney
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Old 11-09-2011, 09:48 AM   #33
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Is this old Furnace Able to be Serviced?


I have been following this thread for a bit now and noticed something today. The pilot light on this furnace is not controlled by the thermocouple. The thermocouple only controlls the main burner. Should the pilot light go out for any reason the gas valve will not turn of the flow of gas to it.
As to can this unit be upgraded...Yes, provided that the heat exchanger is in good shape. A "modern" gas valve and fan control could be retrofitted to this unit very easily. I did one similar about two years ago for a guy who did not want to spend the money on a newer furnace. The fan staying on all the time is most likely due to the fan limit switch either being out of adjustment on the low side or the contacts stuck closed. I have only seen one fan relay like that ever and it was on a unit that we took out of a house so I do not know where the adjustment points are on it or even if the low limit is adjustable.
One other concern is the wrap/coating on the duct work. It is entirely posible that it is some form of asbestos. Before you disturb anything I would at least get a sample tested. In its current state It poses no harm, in fact, it looks like someone painted it which would lock in any loose fibres from escaping. I don't mean to panic you with this but to inform you so you are aware.

Last edited by danpik; 11-09-2011 at 09:53 AM.
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Old 11-09-2011, 11:08 AM   #34
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Is this old Furnace Able to be Serviced?


I'm not sure I'd worry about the pilot gas leaking into the furnace after the thermocouple has shut down a furnace. Too small an amount of gas to accumulate and will just waft up the chimney. A pretty standard design for a furnace of this vintage.
30 seconds of unignited main valve gas failure will destroy a furnace if it finds a sourse of ignition, but that's another story.
You are also right about the probable asbestas wrap. You can see pieces of it in the photo where the vent has been scraped to metal.
Also pretty common, as is the paint covering for this age of unit.
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Old 11-09-2011, 03:38 PM   #35
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Is this old Furnace Able to be Serviced?


It is an old millivolt system with a "standing pilot" not enough gas from the pilot to cause an explosion. Even a modern system with a thermocouple will still pass gas for up to 2 minutes until it cools down and drops out the gas valve. They engineer them so it can pass safely up the chimney with the natural draft and if it ever lights up will blow out the front harmlessly as long as NO combustibles are stored with 2 feet of the front. Causes some laundry stains in the ole shorts but is UL and AGA/CGA tested for a flameout scenario.

Some installers will refuse and have the right to refuse to work on units unless the asbestos is PERFECTLY sealed/encapsulated by paint or removed. Workplace Health and Safety rules etc. Can't say I blame them as once you start shaking the old furnace and banging the ductwork any unsealed fibers can start floating around. Not good for the homeowner either.
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Last edited by yuri; 11-09-2011 at 03:42 PM.
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Old 11-09-2011, 06:38 PM   #36
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Is this old Furnace Able to be Serviced?


Quote:
Originally Posted by danpik View Post
One other concern is the wrap/coating on the duct work. It is entirely posible that it is some form of asbestos. Before you disturb anything I would at least get a sample tested. In its current state It poses no harm, in fact, it looks like someone painted it which would lock in any loose fibers from escaping. I don't mean to panic you with this but to inform you so you are aware.
As far as I know it is 100% asbestos. I had my wife paint it when we moved in to keep the fibers intact. She is a damn good painter. I told her that when I get the new heater, the workers may want to replace the ducts with new non-asbestos wrapped ducts and she said, "Why in the hell did you make me paint them then."
There are many things in this old house that are not safe by modern standards and I'm taking care of them one by one until they are all up to current codes and standards. The paint was added just to buy some time until we install a new furnace. If I can find a contractor who is careful and not afraid of little asbestos, then I will try to use the existing ducts and tell them to be careful cutting away some of the asbestos where the sheet metal will transition from the furnace.

Last edited by vcheez; 11-09-2011 at 08:13 PM.
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Old 11-09-2011, 11:24 PM   #37
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Is this old Furnace Able to be Serviced?


Quote:
Originally Posted by how View Post
Flame spillage can easily be tested out with a source of smoke just an inch above the burners on the line between the inside and the outside of the furnace. A cigarette will do it. When the burners initially light you will get an ignition that might push some excess fumes out of the burner opening area but only for a second or two. This will discolor the area outside of an older furnace above the burners over time. After that, the air in the room should reverse and be flowing into the burner chamber, through the furnace and up the chimney. If you hold a something that produces consistant smoke (cigarette or incense) right at the opening above the burners you will see if spillage (What you don't want) is pushing the smoke away from that opening or if the correct direction of air (smoke)is being pulled into the burner chamber. You can even hold a lit lighter just above the burners and beside the furnace body and if you have spillage, it will put out the lighter flame. Eventually just holding your hand along there will tell you if there is a problem or not. Spillage will produce moist hot air out of the burner chamber whereas a correct direction of air will not.

If it passes your test, do it all again with all the house windows & doors closed and the clothes dryer on. This will create a low pressure area within the house that will most likely produce spillage if your house has insufficient fresh air coming in to counter it.
If it passes this test then, then your unit is not spilling.

Let us know what the result is. This test only indicates spillage and not a cracked exchanger.
Thanks How. You described exactly what I think is happening. I noticed when the burner first starts, a flame comes out of the front for just a second or so. The main section that had fire coming out was that one burner tube that has the most black soot on it. (Second from the left) That was the only spot that for a second or so had an orange flame come out of the furnace for about 2-3". I guess that it why there is a main door that should kept on the front and your not supposed to install combustibles nearby. Shortly after that, when the burner fully ignites, there is no flame outside of the chamber and its mainly a blue flame on the inside. I think that over the 50 or so that years this furnace has been in service and all the times the burner has turned on has caused the damage.

I tried the smoke test without the dryer off and then with the dryer on and in both cases, the smoke was drawn into the furnace. That test was simple and nice and I feel a little bit safer after observing the results.

My fancy CO monitor did not arrive today. I gotta wait one more day. I also ordered a flammable vapor detector. I just figured that it would be nice to measure CO and any non-burned natural gas too.
Well, as per your request, I posted the results of the smoke test. Now what should do? Do you think I could just blow some compressed air up that tube with the soot on it? Maybe it just needs a little cleaning. Thanks in advance, VC

Burner Tube With Most Soot is Where 1-2 Sec Flame Out Occurred
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Old 11-10-2011, 02:09 AM   #38
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Is this old Furnace Able to be Serviced?


A picture directly facing the burners will tell me more but it doesn't look like you have much room to maneuver. Most furnaces of your vintage have more room at the burner opening to inspect and do some long brush work up into the exchanger to remove the soot. If one burner seems to be the problem then the gas/air opening at the front of that burner might have been set up too small. Open it right up to see if you have a dust/debris build up inside the mouth of that burner. Adjust the gas/ air shutter for a bit wider of an opening and fire up the furnace. See if the flames from the problem burner seem to float lower in the burner chamber than the other burner flames.

If they do float lower compared to the other burners then some exchanger cleaning is in order. If you do decide to blow compressed air up into the exchanger then that soot will blast out the opening in the back of this furnace where the chimney vent meets the furnace.
I have been told of people who seal off this opening for the exchanger blow out and send most of the soot up the chimney. There the soot just covers the roof around the chimney for all to see. A poor practice for many reasons.
Another way to gain access for exchanger cleaning is to remove the vent pipe at the back of the furnace to clean downwards with brushes, chains or compressed air and with a vaccum running on top of that burners to collect most of the soot. If you do have soot in the exchanger you are in for a messy job.

Last edited by how; 11-10-2011 at 02:13 AM.
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Old 11-10-2011, 06:30 AM   #39
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Is this old Furnace Able to be Serviced?


If you decide to try clean that unit it should be a COMPLETE proper cleaning procedure or none at all. Once you start blasting air in there the soot and rust will mostly fall back down and onto the burners. You can hire a duct cleaner with a huge vacuum and then spray compressed air in with a flexible hose. When I do a job like that I remove the burners and draft diverter/hood that the vent pioe attaches too. Then the baffles inside the exchanger need to be removed if possible. At that age they could break and crumble from rusting. Damage them and you won't get proper draft thru the exchanger and bad combustion. Once again if you mess with it and cause rust to fall inside the exchanger it may make matters worse and mess up the draft which changes the gas/air mixture and combustion. Gas burning 101.
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Last edited by yuri; 11-10-2011 at 06:37 AM.
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Old 11-10-2011, 12:00 PM   #40
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Is this old Furnace Able to be Serviced?


See if you can arrange a mirror and light to inspect the exchanger area above that burner. Its proximety to the pilot means that you may be only needing to deal with light fluffy white precipitate that is sticking to the upper sides of that part of the heat exchanger. It's whiteness makes it easy to see in there whereas sooting makes it almost impossible. A precipiate build up is enough to cause the burner flame to float. Long bent soft brushes will dislodge that and a running vaccum hose inside that burner will suck up what you dislodge. Another 4" brush into the top end of the exchanger from the vent hood area is the next step if your lower brushing doesn't stop the floating flames.

Last edited by how; 11-10-2011 at 12:05 PM.
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Old 11-12-2011, 12:47 AM   #41
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Is this old Furnace Able to be Serviced?


Thanks guys for the tips on cleaning. That sounds like a really nasty dirty job and I don't think that will be my "cup of tea". I think I would like to hire an experienced person to take care of the cleaning if it involves more than blowing air, vacuuming or brushing.

I do have good news. My commercial monitors arrived today and all is good everywhere I measured for CO and combustible vapors.
I have measured every register in the house, and all areas around the furnace and detected absolutely no CO. I witnessed a factory calibration of the unit today so I know its reading accurately. This furnace might be old and inefficient but is not leaking CO into my home or basement. I checked an 8 hour TWA (time weighted average) of CO exposure at my bedroom register and max CO reading and the values were 0 PPM.

Now that I have established that I am not in immediate danger from CO poisoning, can some one perhaps shed some light on why my furnace fan runs 24 x7 or at least explain how that dial controller works. In the summer, its kind of nice having the fan run all the time because it acts as a poor man's AC as it brings up cool air from the basement. In the winter, it appears to make the heater work more than it needs to because right after the heater warms the house it starts bringing in cool air which drops the temp faster than it would if there was no fan on.
As suggested by one of the other helpful members of the forum, I just spun the controller dial up to 150 and my fan tuned off for the first time. I ran upstairs, raised my thermostat to 72 and then ran back to basement and heard the burner turn on. It ran for about two minutes then the fan started-up. I then ran upstairs dropped the thermostat to 68 and then the burner turned off but the fan continued running for about 3 minutes and then it finally turned off again. It seems that raising the dial up to 150 is making the furnace run properly. Are there any problems with raising the set-point up to 150?

Controller With Temp Raised Setting Raised to 150

If anyone knows how old this this furnace is, I would love to know. I think its from 1942 based on the serial number and the logo, "The Clipper Seaplane" was in service during the 1940's.
I'm beginning to do my research on replacing this furnace, but since I know its not dumping CO into my home, the urgency to replace it has decreased a bit. Thanks in advance, VC

Last edited by vcheez; 11-12-2011 at 01:45 AM.
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Old 11-12-2011, 01:13 AM   #42
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Is this old Furnace Able to be Serviced?


When you move the arm on top of the combination fan control towards the left, does the top glass mercury switch also tilt to the left?
I am wondering if the mercury switch tilts below the horizon to the left, if the fan will shut off?
Be gentle with it!
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Old 11-12-2011, 01:52 AM   #43
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Is this old Furnace Able to be Serviced?


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Originally Posted by how View Post
When you move the arm on top of the combination fan control towards the left, does the top glass mercury switch also tilt to the left?
I am wondering if the mercury switch tilts below the horizon to the left, if the fan will shut off?
Be gentle with it!
The switch was already on the left all of the time and when it was in that position, the fan would not turn off. It makes me a little nervous to mess with these controls especially since I have no instruction manual stating what are the normal settings.
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Old 11-12-2011, 02:17 AM   #44
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OK, a few choices to check out a theory. First we need to confirm that the top glass tube can turn the fan off.
Yes playing with an old control may break it but as this control is made to turn the fan on & off, and it doesn't..you don't have much to lose. I am assuming that you've never seen the top glass tilting below the horizen to the left.

Have you tryed moving the lever on top of the control over towards the right hand side to see if that top glass mercury tube will tilt to the left?

If moving the arm above the control doesn't do it, you can either try to manually tilt it over to the left to see if the fan blower stops..or..
you can turn off the furnace power/ unscrew one of the lines connected to the top glass tube where they are screw connected, isolate that loosened end (tape it or bend it away from conductive metal) and then turn the power back on to see if the fan has stopped.

This is just for testing purposes. The power will need to be turn off again and the wire re attached as it was for the furnace fan to heat the house.

Let us know the results.

Last edited by how; 11-12-2011 at 02:27 AM.
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Old 11-12-2011, 02:30 AM   #45
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Is this old Furnace Able to be Serviced?


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Originally Posted by how View Post
OK, a few choices to check out a theory.
Yes playing with an old control may break it but as this control is made to turn the fan on & off, and it doesn't..you don't have much to lose.

Have you tryed moving the lever on top of the control over towards the right hand side to see if that top glass mercury tube will tilt to the left?
Have you ever seen the top glass tilted below the horizen to the left? If moving the arm above the control doesn't do it, you can either try to manually tilt it over to the left to see if the fan blower stops..or..you can turn off the furnace power/ unscrew one of the lines connected to it, isolate that loosened end (tape it or bend it away from conductive metal) and then turn the power back on to see if the fan has stopped.

Let us know the results.
Ok. I'm gonna give it a try tomorrow morning. It's getting late and I'm tired but please note that by moving the lever to 150, the fan is turning on and off now. It turns on about 2 minutes after the burner starts up and it turns off about 2-3 minutes after the burner turns off. I had the cover on when I was changing the lever position so I don't what the mercury was doing since I could not see it.
I'm not worried about damaging the controller when I move the lever, I'm more concerned about overheating the furnace and causing a dangerous situation since I don't know why there would be a need for the various settings at the furnace. It seems like the variation in temperature should be made from the thermostat. Thx, VC

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