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ITParalegal 06-15-2007 07:46 AM

Thermostat line running through duct intake
I replaced my a/c filter on a house I just bought yesterday and saw something I have never seen before:

The line that connects my thermostat to the outside a/c unit was coming out of the duct work then into the wall.
The thermostat being mounted right above the air intake vent.

I am not sure how far along the line runs through the duct or if the installer just puchtured a hole in the duct and stuck the line in that way.

Is there anything wrong with this?

glennjanie 06-15-2007 10:42 AM

No, nothing wrong. It has worked this long and will probably continue to work. Even if a couple of wires get scrapped bare on the duct metal; it is only 24 volts and won't hurt anything. The most likely scenario would be for it to make two wires contact and lock the thermostat in or some other problem with the thermostat. When it gives a problem; then we'll talk about fixing it.

Square Eye 06-15-2007 10:55 AM

It is illegal to run 120/240 volt wiring in ductwork in romex.
The potential for rattling and wear on the wire's jacket would be reason enough for me to not do this.

ITParalegal 06-15-2007 12:12 PM

Yea, the wires are insulated (they have been wrapped) but I was surprised to see anything when I opened my intake vent cover. I may have it rerun at some later point in the future.

Really, the reason this whole thing came up is because I want to instal a digital thermostat.

I had one in a house I just moved from and felt it gave a lot more ease and precision in heating and cooling my house, resulting in saved money for moi.

I got on ebay and bought a nice honeywell dig therm that retails for around $100 for $45.

Ill go ahead with the install and one of these days look underneath the house just to see what I am dealing with

glennjanie 09-10-2007 11:28 AM

The thermostat wire is only 24v and is not hazardous.


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