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 Repairing and Servicing Lennox Products
 Repairing / Servicing of Lennox Zoning Systems
 Blower/Air Flow problems
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MST

6 Posts

Posted - 01/23/2008 :  11:08:23 AM  Show Profile  Reply with Quote
2.5 ton HP29 / CB31MV (in attic) / 2-zone Harmony II

Blower coil and zoning installed 2003 (HP is 2001) and have worked OK until now. Have two problems I first noticed this week. First, air flow to first floor seems low and very warm compared to how it usually is. Second, when in fan mode, the blower is very noisy and "races." The ductwork sucks, but as noted, system has functioned OK until now.

My guess is the damper for the first floor isn't opening completely. Is this possible, given I'm told it can only be fully open or fully closed? Can this be fixed, or does the damper have to be replaced?

Thanks.

shoe

141 Posts

Posted - 01/23/2008 :  7:07:51 PM  Show Profile  Reply with Quote
I have no Harmony-specific knowledge, but extensive experience with Trolex/TrolaTemp/Zoneatrol, EWC, Durozone & Versatrol zoning. Things have evolved over time, and these days, most zone dampers are of the two-wire variety. Two-wire dampers are typically 'powered-closed' & 'spring-opened'. If the damper is sticking so the blade(s) cannot open completely with the force of the spring, that would explain the behavior. The most common cause of a damper sticking like this is that it doesn't fit the duct properly - it should slide in & out of the duct without 'forcing', and the duct should not deform as the damper mounting screws are tightened.

"Can this be fixed, or does the damper have to be replaced?"

YMMV - if this is the cause, fixing the fit *sometimes* is a permanent solution. Sometimes, damage has been done to the damper and it needs to be replaced.

-------------------------------------------

I am not affiliated with Cozy Parts or Lennox in any way.

The opinions I provide are my own. You have no idea whether or not I'm qualified to hold them. Use them at your own risk.
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dpmelody

2 Posts

Posted - 10/18/2008 :  11:27:22 AM  Show Profile  Reply with Quote
quote:
Originally posted by shoe

I have no Harmony-specific knowledge, but extensive experience with Trolex/TrolaTemp/Zoneatrol, EWC, Durozone & Versatrol zoning. Things have evolved over time, and these days, most zone dampers are of the two-wire variety. Two-wire dampers are typically 'powered-closed' & 'spring-opened'. If the damper is sticking so the blade(s) cannot open completely with the force of the spring, that would explain the behavior. The most common cause of a damper sticking like this is that it doesn't fit the duct properly - it should slide in & out of the duct without 'forcing', and the duct should not deform as the damper mounting screws are tightened.

"Can this be fixed, or does the damper have to be replaced?"

YMMV - if this is the cause, fixing the fit *sometimes* is a permanent solution. Sometimes, damage has been done to the damper and it needs to be replaced.

-------------------------------------------

I am not affiliated with Cozy Parts or Lennox in any way.

The opinions I provide are my own. You have no idea whether or not I'm qualified to hold them. Use them at your own risk.



Shoe,
You mentioned you had extensive experience with Versatrol zoning systems. We had one in our home when we moved in and it doesn't seem to work right. It is a 4 zone system and there are 2 Versatrol (U B7000) control units. I don't have any manuals for it. Do you happen to know where I could get a manual or information on wiring for the control unit?
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