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raharra
04-19-2008, 10:29 PM
I had a residential Coleman furnace that had a sticky combustion blower diff. press. switch. The part came in and I got it replaced/retested today, sat.:cool:

My questions are:
-the two ports were labeled "+P" and "V", which I assume meant positive pressure and vacuum. Yet, the (factory installed)tubes were connected to the combustion pipe exhaust fan on the suction and discharge sides respectively. Am I interpreting the labels correctly?
-On the "+P" side of the new switch, the port had a small tubing piece inside with a hole bored thru it, I guess that you would call it a sleeve inside the port. Only on the "+P" side (I searched the box for any missing sleeve for the other port, no dice), not the "V" port. What the heck is the purpose of that sleeve?

Plus, I have to say that I was pretty impressed with the flashing diagnostic light on this furnace. I had figured the intermittant problem was due to a dirty flame sensor until the board gave me the code for a failed combustion switch. Then, the homeowner informed me that the guy who used to work on his furnace (before he died) told him he had a sticky switch. He would tap the combustion d/p switch and it would work just fine for a while.
I was happy to have that diagnostic board telling me the same thing the homeowner was; it made selling him a new d/p switch a cinch.
I wish all of them were that easy.

Senior Tech
04-19-2008, 11:17 PM
Your either a diy'r or very, very new to the trade...please read the rules before posting further.

beenthere
04-20-2008, 01:44 AM
You sound new to service. Or a DIYer as ST said.
Boards with diagnostics been arounf for a long time now.

Get your post count up, and apply for pro membership.
Then you can post in the pro tech forum and find out about the other advanements in control boards.

And yes, that restrictor does belong on only that one port.

raharra
04-20-2008, 08:05 AM
I did not realize that I had broken your posting rules. Sorry about that.

No, most of the electric furnaces or ancient gas ones that I have worked on did not have a control board indicator. Not too many customers around here get the urge to spend any more than is absolutely necessary on their HVAC units.

I am just trying to learn something about the trade beyond the rudimentary level of replacing broken parts. Did not mean to impose.

I will find my answers elsewhere.

caliweath33
04-20-2008, 08:09 AM
how many people have died due to co

beenthere
04-20-2008, 08:21 AM
I am just trying to learn something about the trade beyond the rudimentary level of replacing broken parts. Did not mean to impose.

I will find my answers elsewhere.

Are you in the trade.

If so, and you became a pro member. You would find the amount of knowledge on this board is priceless.

EG: In the Tech forum, there was a recent debate on weather or not. You would actually be able to freeze the moisture and change it to ice if you use too large of a vacuum pump.
One of the members did the test last night. And posted his results.
With the number of pro members here. There aren't too many brands, that someone hasn't worked on.

Your choice to join or not.
Its expensive. $0.00 to join, plus $0.00 each month. :)