No cooling from furnace

Not sure what the problem is, but need yr advice.
I have a 2 storey house in Calgary Canada. In the basement we have Our Gas furnace and on main floor thermostat which had been working fine. They are around 10 years old. We have a analog, HeatCraft brand thermostat. Since few days heat has stopped flowing thru the ducts, all ducts seem to be as cold as ice...I live up north in Canada, so the -20deg Celcius is unberable. When I lower the temp of the thermostat to 12 or 13, the furnace seems to go off (I guess bcoz room temp is higher then 12), but increasing it to 25 doesnt seem to make any difference. When set to 25, the furnace does shut off for some time maybe 20 mins (not very sure), and then comes on. The temp I see on the Thermostat needle is then around 17....It never seems to go over 17. The furnace is of Lennox brand, and it seem to be working well. The aluminum pipes connected to the furnace in the basement of my 2 storey house seems to be quiet hot..I cannot touch it for more then 2 seconds. Its surprising that although those pipes are hot, yet no air blowing from all ducts....Please recommend...I dont mind calling a contractor, but if it is a simple thing I could fix, then that would save lots of $$$. Is this a thermostat problem or a furnace problem. Can it be fixed by changing the thermostat. A naive fried told me it maynot be a thermostat problem as whne the temp is lowered to 12 deg, the furnace does shut off....but its surprising why it doesnt remain on too keep the house temp at 25.

 

Is the filter clean? Is the blower runnig? Are there dampers in the trunk line that are closed?

 

The filter was replaced 3 weeks ago..

How would I check if the blower is working, or if no dampers r closed. Any pointers to these verification will be appreciated..Meanwhile I google for such checks. thank u

 

Does the blower try or make any noise?? It sounds like its the blower motor and you have to get it fixed right away. From what you say the furnace is going off on high limit . So Id say call a tech now .

ED

 

Since yday, I left the thermostat at 20, and the needle now shows 20 deg (yday it was showing 17 deg...which means the thermostat is probably working)..The furnace now at 20 deg goes on for 30 sec, then shuts off, and then goes on after 2 to 3 mins of shutdown...There is a constant motor noise coming out of the furnace, which means motor is running all the time, thus doubt if blower is not working (I presently have no idea how to verify if blower is working as expected). I increased the thermostat from 20 to 24 deg, still the burner shows the 2o seconds on, and 2 to 3 mins off fluctuations.

Also, about the pipes, I find the round pipes which go fom the lower end of the furnace to be hot...but the rectangular ones which act as ducts are just warm....I guess this is normal

My interest is thus off no good heat transfer when thermostat is above 20 degrees.

 

I still say call a tech to look at it . It sounds like the blower dont come on and the furnace is going on and off on the limit control.

 

Have you tried switching the t-stat fan swith from Auto to ON?

if you do that and notice air flow out of the vent, then your blower is in't running in heat mode.

You should feel air blowing out of the vents anytime the heat/cool comes on.

if you do get air out of the vent with the fan ON, you may leave it on till you get it fixed.

 

Since i travel a lot..One bad day in -40 deg cel, the furnace finally gave up, remialing ice cold...so my wife called a tech who ripped us off with $150...

he said that the board needs to be replaced..to get the fan running he said there was a relay inside the control module and the relay was gone bad...so he connected both the wires of the relay to get it started..now the fan runs continuously all the time.
he said the furnace is a 1996 , model diplomat..
He told us to get it working as expected, the board needs to be replaced..the cost would be $350 for board and $150 labour.....
well...sure a big ripoff, I need guidance from all you experts on what this board would cost and how easy is this labour...
Please do reply as the situation is very urgent. The technical also told me most people leave the board with relay shorted for months.

Need advice please?

On outside the furnace, it says the Model is LENNOX 10,000 BTU, but the technicial said its "1996 furnace model diplomat"

 

That don't sound like a bad price to me at all.

 

A question...is the connection, i..e bypassing the relay and shorting those wires directly acceptable, or is it a bad practice causing heavy damage.

On other postings it seems such control modules cost $150 or so...so isnt $350 very high...any clue what places online sell this control module, and what and where part number should I be looking for

 

Here are some to try for a board. Lennox parts are high. I think the labor there is high. Thats $300 to say a board is bad and put a new one in


http://bestbuyheatingandairconditioning.com/Merchant2/merchant.mvc?


http://www.heatcoolparts.com/

http://www.expertappliance.com/heating.html