Articles:
Lung Cancer and YOUR Furnace or Boiler 

SHERIDAN MECHANICAL SERVICES
    Serving the perimeter of Denver, CO.
  (303) 669 - 3876

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A FURNACE PRINTED CIRCUIT BOARD.

Below are (3) Printed Circuit Boards. The one on the left is for a York furnace, the middle one is for a Goodman/Janitrol furnace and the right one is for a Tempstar furnace. These boards in modern furnaces control all operations of the furnace from safety controls, burner operation, air conditioning operation and indoor blower operation. They can not be "jumped out" even temporarily.

As you can see, they are totally different and are made for the particular furnace brand and the particular model number of that particular furnace! When you stop to think that there are nearly 100 different brands of furnaces on the market and each manufacturer may have 3 or 4 different boards used, you can see why NO Heating and Air Conditioning Service company can possibly keep all the boards in stock, let alone on each service truck.

On top of this situation many furnace manufacturers change boards in the middle of a production year. Another annoying thing that happens to us while servicing a furnace is as follows.

We arrive at a job and through electrical diagnosis, determine that we have a bad circuit board. We go get a new board, return to the job site, open the box and find that the board manufacturer has made upgrades or other changes to their board which now requires us to go through a complex re wiring of the control wiring! If we have already quoted a price to change the board to our client, we are in the situation that requires us to change our price or lose our labor on the job. This may look like we are trying to take advantage of the client but this is a real world problem that happens sometimes.

Below is a shot of a defective board which has been either hit by lightning or has had a 
power surge. We apologize for the poor photo but to get close enough with the camera to
show the brown discoloration sacrifices the photo quality.

Below is a shot taken with a higher resolution and therefore a bigger picture, note the black 
spots on the board? This board is shorted out and needs replacement. We suggested that our
client have whole house surge protection installed by a licensed electrician.

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