Furnace not working - Tilted Forum Project Discussion Community

pook · 12-11-2004, 04:18 PM

The furnace for my main floor isn't working right. It's about 6 years old. There's a small blower that's running nonstop, but the main blower never kicks on.

Since it's newer there's no pilot light. A pal thinks it's the electric ignitor that's bad. It's not working so the gas never runs and the blower never goes.

The model is Heil.

eribrav · 12-11-2004, 06:42 PM

There's some projects I'm willing to tackle, but the furnace generally isn't one of them. There's just too much possibility of catastrophic error involving nat gas, carbon monoxide, etc. I'd get a professional in. Sure that will be expensive over the weekend but well worth it in the long run.

Bossnass · 12-12-2004, 10:39 AM

Is the hot-point ignitor trying to click on. A period 'snap' will indicate that it is. If so, the ignitor may be good and you don't have gas/ have an apature problem. If it isn't, then it is probably the problem, which is an easy fix.

Either way, it is probably the best course of action to get a professional in. I always get this darwin alarm going off in the back of my head whenever I'm doing anything where NG is involved.

kazoo · 12-12-2004, 11:35 PM

The small fan that is running is called a draft inducer blower. It is the first device ordered to start by the control board upon a call for heat by the thermostat. One problem with the units of that vintage is that all the little kinks of meduim-high efficiency weren't worked out. From that draft blower is a piece of soft tubing that loops over to a diaphragm with a microswitch on it. Pull the tubing off the diaphragm (you don't need to shut anything off) and hold it down from the blower. Expect a half-teaspoon of water to come out. Reattach the hose to the diaphragm, and there should be an almost immediate 'click' as the diaphragm verifies blower operation and closes the switch. Once that switch closes, the hot surface igniter is energized, heat feedback authorizes pilot, cad cell eye verifies pilot, main flow gas is authorized, and main burner fires. Hot surface igniter is de-energized, and cad cell eye monitors main burner and will cut off gas if flame fails, rollout heat sensor activates, high limit safety activates, or blockage occurs in the flue, which would cause the diaphragm switch to open. Otherwise, once the heat exchanger is warmed, the main fan will come on and you'll have heat until the thermostat is satisfied.

kazoo · 12-12-2004, 11:42 PM

Just in case you haven't tried to get to anything yet, assuming the unit to be an ordinary Heil vertical updraft furnace, the fan that you hear and the hose that you need to get to are behind the upper louvered access panel that you're staring at when you approach the heater. Lift up about a half inch and the panel should come off. Don't play with the solid panel beneath it unless you have to. That panel must be reinstalled correctly or the main safety switch will lock out and nada will run. :no heat smiley:

Locke7 · 12-13-2004, 08:17 AM

Wow that was technical. Think we have a furnace guy here on the forums.

I'm no furnace guy, but I had the same problem, TWICE. And all you guys talk about darwin awards is a good point. The more I look back, the worse I feel. One wrong move and I could have been toast, literally.

But I'm a DIY guy so I had to try, and it worked both times. So here goes, very non technical description of what I did.

First time, draft inducer blower (heh, picked that up from kazoo) would turn on, glow plug would light up, gas would turn, and furnace would function for about 10 seconds, then just turn off. It would try this about ever 2 minutes. It ended up being the flame monitor (maybe the cad cell eye in kazoo's post??). It is a small cylinder that is up in one of the flames. It was dirty. They said to clean it off with an emery cloth, so I used one of my wifes emery boards. Worked like a champ.

Second time, draft inducer blower would fire up, but glow plug would never turn on. Took it out and realized that it had a crack in it, got a new one from a local utility place, installed it, and everything went back to working.

This thing breaks down one more time, I'm calling a pro.

MSD · 12-13-2004, 04:10 PM

Quote:

Originally Posted by kazoo

The small fan that is running is called a draft inducer blower. It is the first device ordered to start by the control board upon a call for heat by the thermostat. One problem with the units of that vintage is that all the little kinks of meduim-high efficiency weren't worked out. From that draft blower is a piece of soft tubing that loops over to a diaphragm with a microswitch on it. Pull the tubing off the diaphragm (you don't need to shut anything off) and hold it down from the blower. Expect a half-teaspoon of water to come out. Reattach the hose to the diaphragm, and there should be an almost immediate 'click' as the diaphragm verifies blower operation and closes the switch. Once that switch closes, the hot surface igniter is energized, heat feedback authorizes pilot, cad cell eye verifies pilot, main flow gas is authorized, and main burner fires. Hot surface igniter is de-energized, and cad cell eye monitors main burner and will cut off gas if flame fails, rollout heat sensor activates, high limit safety activates, or blockage occurs in the flue, which would cause the diaphragm switch to open. Otherwise, once the heat exchanger is warmed, the main fan will come on and you'll have heat until the thermostat is satisfied.

Wow. That was educational. I was just going to tell him to call a repairman so he doesn't blow himself up.

kazoo · 12-13-2004, 05:47 PM

Always glad to help. Emails are welcome, too. Fixin' stuff is what I do.

12-11-2004, 04:18 PM	#1 (permalink)
pook Registered User	Furnace not working The furnace for my main floor isn't working right. It's about 6 years old. There's a small blower that's running nonstop, but the main blower never kicks on. Since it's newer there's no pilot light. A pal thinks it's the electric ignitor that's bad. It's not working so the gas never runs and the blower never goes. The model is Heil.

12-12-2004, 11:35 PM	#4 (permalink)
kazoo Psycho Location: Where the night things are	The small fan that is running is called a draft inducer blower. It is the first device ordered to start by the control board upon a call for heat by the thermostat. One problem with the units of that vintage is that all the little kinks of meduim-high efficiency weren't worked out. From that draft blower is a piece of soft tubing that loops over to a diaphragm with a microswitch on it. Pull the tubing off the diaphragm (you don't need to shut anything off) and hold it down from the blower. Expect a half-teaspoon of water to come out. Reattach the hose to the diaphragm, and there should be an almost immediate 'click' as the diaphragm verifies blower operation and closes the switch. Once that switch closes, the hot surface igniter is energized, heat feedback authorizes pilot, cad cell eye verifies pilot, main flow gas is authorized, and main burner fires. Hot surface igniter is de-energized, and cad cell eye monitors main burner and will cut off gas if flame fails, rollout heat sensor activates, high limit safety activates, or blockage occurs in the flue, which would cause the diaphragm switch to open. Otherwise, once the heat exchanger is warmed, the main fan will come on and you'll have heat until the thermostat is satisfied. __________________ There ain't nothin' more powerful than the odor of mendacity -Big Daddy

12-12-2004, 11:42 PM	#5 (permalink)
kazoo Psycho Location: Where the night things are	Just in case you haven't tried to get to anything yet, assuming the unit to be an ordinary Heil vertical updraft furnace, the fan that you hear and the hose that you need to get to are behind the upper louvered access panel that you're staring at when you approach the heater. Lift up about a half inch and the panel should come off. Don't play with the solid panel beneath it unless you have to. That panel must be reinstalled correctly or the main safety switch will lock out and nada will run. :no heat smiley: __________________ There ain't nothin' more powerful than the odor of mendacity -Big Daddy

12-13-2004, 05:47 PM	#8 (permalink)
kazoo Psycho Location: Where the night things are	Always glad to help. Emails are welcome, too. Fixin' stuff is what I do. __________________ There ain't nothin' more powerful than the odor of mendacity -Big Daddy

12-11-2004, 06:42 PM	#2 (permalink)
eribrav Junkie Location: upstate NY	There's some projects I'm willing to tackle, but the furnace generally isn't one of them. There's just too much possibility of catastrophic error involving nat gas, carbon monoxide, etc. I'd get a professional in. Sure that will be expensive over the weekend but well worth it in the long run.

12-12-2004, 10:39 AM	#3 (permalink)
Bossnass Détente Location: AWOL in Edmonton	Is the hot-point ignitor trying to click on. A period 'snap' will indicate that it is. If so, the ignitor may be good and you don't have gas/ have an apature problem. If it isn't, then it is probably the problem, which is an easy fix. Either way, it is probably the best course of action to get a professional in. I always get this darwin alarm going off in the back of my head whenever I'm doing anything where NG is involved.

12-13-2004, 08:17 AM	#6 (permalink)
Locke7 Insane	Wow that was technical. Think we have a furnace guy here on the forums. I'm no furnace guy, but I had the same problem, TWICE. And all you guys talk about darwin awards is a good point. The more I look back, the worse I feel. One wrong move and I could have been toast, literally. But I'm a DIY guy so I had to try, and it worked both times. So here goes, very non technical description of what I did. First time, draft inducer blower (heh, picked that up from kazoo) would turn on, glow plug would light up, gas would turn, and furnace would function for about 10 seconds, then just turn off. It would try this about ever 2 minutes. It ended up being the flame monitor (maybe the cad cell eye in kazoo's post??). It is a small cylinder that is up in one of the flames. It was dirty. They said to clean it off with an emery cloth, so I used one of my wifes emery boards. Worked like a champ. Second time, draft inducer blower would fire up, but glow plug would never turn on. Took it out and realized that it had a crack in it, got a new one from a local utility place, installed it, and everything went back to working. This thing breaks down one more time, I'm calling a pro.