It sounds to me that your board is the problem. When your stat turns on by temp. the blower has to start first, once the blower starts it opens your sail switch then once that is proven it will allow you ignitor to light. That's a safety built in. In order for you to have what you described I would say that you really have 2 problems. Being I said that it is very possible that your fan center is out (or as some call it your board). I would not close any registers as suggested being if you do the correct cfm will not be exhausted and cause limit problems.(over heating) Check to see if you have 12v at the modular should be red going in and a red going out to the blower. If you have your book yet(Suburban)on it check figure#5 0n page #5 if you do it's the blower more then likely. If you do not have your book here it is
Ok, thanks. I will have to get it out today and get things checked out.
I guess I'm thinking about it differently.
Less resistance more vents.
More resistance less vents.
Trying blowing air through one straw then try blowing air through four straws which is easier?
Thoughts?
What say you glen gjurizick "lol"
Stick your hand over the hose on a shop vac - The motor speeds up.
Block the inlet on a leaf blower- the motor speeds up.
Stick your hand over the suction on a dust buster, the motor speeds up.
Blocking a vent could actually lower the amps on a furnace blower but
this is likely not the OPs problem.
__________________ Peace! Dan & Rita D
2017 Nissan Titan 5.6L King cab 4wd
2016 Evergreen Everlite 242RBS
29' empty nest model. Blue Ox WD hitch
(1 queen bed, large main cabin and huge bathroom)
Camping days 2010-53, 2011-47, 2012-41, 2013-41, 2014-31, 2015-40, 2016-44, 2017-63, 2018-75, 2019-32, 2020-41, 2021-49, 2022-43, 2023-66
If a squirrel cage blower "over RMS's" at no load situation it will over amp a little....or at least an AC current one will. I would think brushless DC motors would not experience this because of voltage variations.
The problem that is caused is that your blower can not move the air out fast enough and it will cause the unit to over heat. To put it simply your limit is set by heat disk as the temp climbs from not blowing enough air over the heat exchanger the bimetal will bend and open shutting the furnace down. Your blower will not speed up to blow a fuse. If anything your cfm would be reduced because of the static pressure it now has to over come.(can not exhaust enough hot air) Which will create a hotter heat exchanger that the disk is connected on. it could be rated at 115 degrees or 135 it should be stamped on it. It's important to get the rated replacement. I never had a meter on one but with DC it should stay the same. The fuse should be rated at 10% over the full load motor amps. If a person keeps doing that I guarantee you that it will crack your heat exchanger.
Stick your hand over the hose on a shop vac - The motor speeds up.
Block the inlet on a leaf blower- the motor speeds up.
Stick your hand over the suction on a dust buster, the motor speeds up.
Blocking a vent could actually lower the amps on a furnace blower but
this is likely not the OPs problem.
On any squirrel cage fan, if you block an inlet, you 'unload' the fan and the speed increases and current draw will drop. Opening the fan inlets load the fan, decrease the speed and increases current draw. Blocking an outlet will increase the static pressure and increase the current draw.
On any squirrel cage fan, if you block an inlet, you 'unload' the fan and the speed increases and current draw will drop. Opening the fan inlets load the fan, decrease the speed and increases current draw. Blocking an outlet will increase the static pressure and increase the current draw.
Back to the OPs problem....
The furnace "just clicks" and nothing else.
My furnace does not have separate fuse for fan motor and control board.
One fuse does it all.
If mine just clicked it would probably mean the fan relay was coming on
but the fan motor was not turning.
I'd expect to blow a fuse if the motor was locked up or blocked by wasp
nest.
As mentioned earlier it could be a dead spot on the blower motor but that's
pretty rare.
Could be bad relay or loose wire between relay and motor.
This one's gonna be hard to trouble shoot thru a keyboard.
I hope they have aux heat! It's pretty cold just about anywhere in North America right now!
I did see where Key West was in the 80s.....
__________________ Peace! Dan & Rita D
2017 Nissan Titan 5.6L King cab 4wd
2016 Evergreen Everlite 242RBS
29' empty nest model. Blue Ox WD hitch
(1 queen bed, large main cabin and huge bathroom)
Camping days 2010-53, 2011-47, 2012-41, 2013-41, 2014-31, 2015-40, 2016-44, 2017-63, 2018-75, 2019-32, 2020-41, 2021-49, 2022-43, 2023-66
Back to the OPs problem....
The furnace "just clicks" and nothing else.
My furnace does not have separate fuse for fan motor and control board.
One fuse does it all.
If mine just clicked it would probably mean the fan relay was coming on
but the fan motor was not turning.
I'd expect to blow a fuse if the motor was locked up or blocked by wasp
nest.
As mentioned earlier it could be a dead spot on the blower motor but that's
pretty rare.
Could be bad relay or loose wire between relay and motor.
This one's gonna be hard to trouble shoot thru a keyboard.
I hope they have aux heat! It's pretty cold just about anywhere in North America right now!
I did see where Key West was in the 80s.....
Dan the op problem is that it is trying to light. The ignitor will not try unless the sail switch closes to prove the air flow. If his fan is not turning he should not be hearing any clicks on trying to light. That circuit has to close first as stated. it wired in series as the diagram shows. more then likely he will find a short or a bad modular. By the way did you get yours running yet? I'm assuming he not just hearing the stat click when turned to heat, sounded to me he was hearing the ignitor. Maybe we will hear if he gets heat I hope so Bad time to be without during this freaky weather pattern. If it is the stat he talking about(the Click) then the sub base could have gone out. He would just have to jumper RH to white to bypass that. I'm not sure what colors where used but that is normally the combination.
He said he hears a click.
Donno if it's the thermostat or the fan relay.
I agree it's not gonna try to light without the fan running.
I have dino board on order.
Shipped last week. Got a tracking # but USPS says "no information" when
I try to track it. Sheesh..... It'll come this week unless the mail truck gets
stuck! It's gonna be cold this week so I'll probably put it in the furnace
in my shop and not re-install until it warms up above freezing one day!
__________________ Peace! Dan & Rita D
2017 Nissan Titan 5.6L King cab 4wd
2016 Evergreen Everlite 242RBS
29' empty nest model. Blue Ox WD hitch
(1 queen bed, large main cabin and huge bathroom)
Camping days 2010-53, 2011-47, 2012-41, 2013-41, 2014-31, 2015-40, 2016-44, 2017-63, 2018-75, 2019-32, 2020-41, 2021-49, 2022-43, 2023-66
So you say when you turn on the thermostat you hear a click and
nothing else.....
WHERE is the click?
My thermostat clicks when it "is calling" for heat.
A second or 2 later -
My furnace clicks and I hear the fan start immediately.
Is your click coming from the furnace or the thermostat?
Still gonna be hard to trouble shoot from here.
Good luck!
This is the OP, I haven't had the opportunity to work on the furnace yet, we are staying at a house for a few days. There is ice and snow everywhere right now.
I HIGHLY APPRECIATE all the feedback that I am getting from everyone.
I had to do a quick winterize to make sure nothing froze up. But as soon as I can I will put all of your great advise to work. Then I will let everyone know what I had to do to get it fixed. Thanks again!!
So you say when you turn on the thermostat you hear a click and
nothing else.....
WHERE is the click?
My thermostat clicks when it "is calling" for heat.
A second or 2 later -
My furnace clicks and I hear the fan start immediately.
Is your click coming from the furnace or the thermostat?
Still gonna be hard to trouble shoot from here.
Good luck!
Oh I can hear the thermostat and the furnace click, it even sounds like it is going through its cycle of trying and then shutting down.
Aren't they separate impellers on a common shaft...why wouldn't blowing air into the intake or exhaust port not turn the common shaft?
Dave
Yes, one motor; common shaft with 2 squirrel cage fans; one inside the plenum and one outside to provide combustion air.
Clicking means the fan and motor is OK.
No ignition with clicking means you need to look at mixture.
Propane? Y/N - Does range have tall blue flames with ALL ON?
Solenoid Valve Open? Y - smell gas when clicking N - no gas smell
Mixture? Obstruction in flue too rich - Obstruction in jet - too lean.
Clean out flue with compressed air
__________________
Lou & Freya the wonder dog
2008 GMC Sierra 3000HD Allison Duramax
2019 Flagstaff 8529FL
Back to the OPs problem....
The furnace "just clicks" and nothing else.
My furnace does not have separate fuse for fan motor and control board.
One fuse does it all.
If mine just clicked it would probably mean the fan relay was coming on
but the fan motor was not turning.
I'd expect to blow a fuse if the motor was locked up or blocked by wasp
nest.
As mentioned earlier it could be a dead spot on the blower motor but that's
pretty rare.
Could be bad relay or loose wire between relay and motor.
This one's gonna be hard to trouble shoot thru a keyboard.
I hope they have aux heat! It's pretty cold just about anywhere in North America right now!
I did see where Key West was in the 80s.....
________________
My fan was doing the same thing had to replace fan motor. Plus there was a trailer in the CG this year that the fan would not run. The fan motor was accessible from the outside. We could move the fan motor 1/4 turn and furnace would start up. It ran several cycles till it stopped on the bad spot again and not run. Turn motor and away it went. Had to change fan motor, he has not hat a problem since.
__________________
Terry and Janet
2008 3001W Windjammer
2007 Ford F150
On any squirrel cage fan, if you block an inlet, you 'unload' the fan and the speed increases and current draw will drop. Opening the fan inlets load the fan, decrease the speed and increases current draw. Blocking an outlet will increase the static pressure and increase the current draw.
Yes, one motor; common shaft with 2 squirrel cage fans; one inside the plenum and one outside to provide combustion air.
Clicking means the fan and motor is OK.
No ignition with clicking means you need to look at mixture.
Propane? Y/N - Does range have tall blue flames with ALL ON?
Solenoid Valve Open? Y - smell gas when clicking N - no gas smell
Mixture? Obstruction in flue too rich - Obstruction in jet - too lean.
Clean out flue with compressed air
Herk, The fan motor needs to be running to close the sail switch which is normally open N/O per the wiring diagram. OP say's it is not running. If the switch will not close from the air flow the ignitor should not be trying to lite. Sequence go's from stat to fan to limit n/c to sail switch n/o to ignitor. If any of those do not close to pass power there is no way possible the ignitor should work unless there is a short in the modular. The fan has to be proven before the ignitor should click 3 x's unless he is hearing the stat only click, then it's a bad sub base not making contact. easy to prove just jumper RH to W on the base. It is pure injection being nobody is taking a reading with a meter. But possible things to check by his (OP) description. Things he might not have thought about.
We still haven't got a firm answer on whether Steve's fan motor is
running or not.
Guess this one's on the back burner till he has time and agreeable
weather to diagnose further.
I stand corrected (again). Trouble with too many problems in the same thread.
If the fan motor does not run, nothing will happen as they say. If the fan runs too slow, nothing will happen. The sail switch must close to get power to the ignition control board's ignition circuits.
Causes of NO rotation:
Very rusty/corroded motor shaft
Bad commutator in the motor (flat spot)
Burned out motor
Blown fuse (main in power center or fuse at furnace) (see photo)
Large Mud Dauber nest that attaches the fan to the metal enclosure
Bad Gas solenoid Valve (N.C. side is open)
Bad main control board
Causes of SLOW rotation (not enough air flow to close plenum switch (sail)
slightly rusty/corroded motor shaft
Bad motor (slow rotation)
Mud dauber nest inside fan (low air flow - slow rotation)
I understood the "clicking" to mean the ignitors are trying to light the gas.
My bad.
__________________
Lou & Freya the wonder dog
2008 GMC Sierra 3000HD Allison Duramax
2019 Flagstaff 8529FL
Linear Mode
