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Can I disconnect BlendAir permanently?

Posted: Thu Oct 31, 2013 1:07 pm
by kharndt
I have '92 Nashua with Blend Air 7681-7701 installed. Had furnace serviced today and asked tech to look at the Blend Air motor because it's become unbearably loud and I can't sleep. Options he offered were to replace the motor or permanently disconnect it. He said I had plenty of roof venting and that disconnecting Blend Air shouldn't cause any moisture problems. Thoughts?

<a href="http://www.flickr.com/photos/32698746@N02/10595240955/" title="photo 1 by kharndt, on Flickr"><img src="http://farm6.staticflickr.com/5545/1059 ... c92c_o.jpg" width="542" height="214" alt="photo 1"></a>

Re: Can I disconnect BlendAir permanently?

Posted: Thu Oct 31, 2013 3:59 pm
by DaleM
You can disconnect it. Without the motor it will be a passive system. When the blower comes on it will pull fresh in through the flex duct.

Re: Can I disconnect BlendAir permanently?

Posted: Thu Oct 31, 2013 4:18 pm
by kharndt
Dale, thanks for responding! I've seen posts on how to disconnect, so I know it can be done.
1. Without Blend Air will the roof vents I have be adequate to keep the air moving (and moisture at bay)? Can you clarify: when you say "...when the blower comes on..." I assume you mean the furnace blower, correct?
2. Can it be turned off, or does it have to be unwired?

I so appreciate your help!!

Re: Can I disconnect BlendAir permanently?

Posted: Thu Oct 31, 2013 11:34 pm
by DaleM
There is a flex duct connected to the top of the furnace. Inside that duct, on top of the furnace, is an automatic damper....if so equipped. That damper should get either jammed open or removed to allow free flow of air into the furnace cabinet. The fan motor of the Blend Air system located in the roof vent assembly need not be messed with other than having it's wiring disconnected at the furnace. Basically you're just changing an active Blend Air system into a passive Blend Air system by using the blower of the furnace to pull fresh air into the home via the Blend Air ducting. The original system used a small fan motor to force that air into the furnace. Hope that answers your questions.

Re: Can I disconnect BlendAir permanently?

Posted: Tue Nov 05, 2013 10:08 am
by kharndt
One last question -- or rather, confirming that what I will do is correct. In the photo, I am holding the green connections. I will pull the darker green wire (from Blend Air) out of that cluster and cap it with a wire nut. That leaves the thicker light green from the furnace and the thin green wire to the thermostat. I'll repeat for the red and white.

Anything else, besides taking care of the damper? Do I need to pull the white plug at the top of the Blend Air box?

This a great forum and I'm so appreciative of everyone who helps out!

Image

Re: Can I disconnect BlendAir permanently?

Posted: Mon Nov 11, 2013 1:09 am
by DaleM
Yep, just pull the Blend Air wiring out of all the connections and leave all other wiring intact.

Re: Can I disconnect BlendAir permanently?

Posted: Thu Nov 14, 2013 10:00 am
by kharndt
Thank you!!

Re: Can I disconnect BlendAir permanently?

Posted: Sat Nov 16, 2013 6:52 pm
by kharndt
Dale (and anyone else reading) -- I completely disconnected the BlendAir unit, as discussed in the previous posts to this thread, and it's still running. What now?

I'm holding all of the disconnected wires

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Re: Can I disconnect BlendAir permanently?

Posted: Sun Nov 17, 2013 6:14 pm
by DaleM
Must be another switch up near the motor in the Blend Air roof vent assembly. It could be humidity operated or temperature operated as an override to the low voltage wiring you have already disconnected. OR the switch I speak of is stuck in the ON position. You will have to go on the roof and just disconnect the primary wiring to the unit. Be sure to kill the breaker first. All that should be located under the Blend Air roof jack cap.

Re: Can I disconnect BlendAir permanently?

Posted: Sun Nov 17, 2013 6:47 pm
by kharndt
Thanks, Dale!! I'll give that a try.