Why does my new furnace continue to shut down?

[tjweidler]

I have a Carrier 8000VS that was installed in June of 2003. We have had the same repeated problem during both winter seasons since we had it installed. It shuts off indicating that the filter is dirty. We change the filter twice a month and use high grade filters but not anything special. The filters are always black or near black. The company blames it on burning candles. We may burn one or two high grade candles in the house at a time for a couple of hours2 or three times a week. My heating Co. told me to either stop burning candles or to buy the cheap filters and let the soot pass through. We have one dog which doesn't seem to be the problem either. Our old furnace functioned fine with 2 dogs and the same candle burning. I realize the new furnace is "smart" so that it can sense and shut down when the filter is dirty - but my question is with how often we are changing the filter and because of the difference I see in the filters between our old and new furnace could it be something other than burning an occasional candle? I just want reassurance that there is not a problem with this furnace that may be causing the filter to blacken so quick. Thanks for any info you can give.

[stef]

You should not have any problem with burning candles for your enjoyment. It is not like you just started it.

I recommend you to use 4 inches pleated filter to catch the soot a litle better. This filter has more surface area, which catch more dirt and less ristrictive. If any filter let the salt go thru, it ain't doing the job of catching dirt.

DON"T LET ANY CONTRACTOR TELL YOU THAT YOU NEED TO USE THOSE CHEAP FIBERGLASS FILTER BECAUSE YOU DON'T HAVE ENOUGH AIR FLOW. If you don't have enough air, they they should have seen it and do comething about it.

As far as the unit is shutting off. When you take out you filter hold it up to a light - Can you still see the light? If so, then have the contractor out to either recalibrate the sensor differential. Or to replace the sensor.

I am curious - what size is your system (tons)? and what size is your filter?

Have fun

[Wild Leg]

Prove or disprove the company's candle theory by doing without the candles for a month.

See if that makes any difference.

Store the old filter in a plastic bag, so that you can compare them in a month.

[tjweidler]

The only thing I can tell you about the furnace is that it is a Carrier 8000VS 58UHV size 060-12. I just know noticed that the manual states to use a 16x25x1 filter and we were told to use 16x20x1. Also it doesn't appear that the 16x25x1 will fit in the filter cabinet that they attached to the system.

[stef]

Please find out, then let us help you.

[millerman]

Lets ponder this one, Black filter that shuts down the furnace. 2 times a month? Keep in mind the filter is cleaning the return air in your house. I doubt that the furnace is producing black soot so where is it comming from? Candles? could be, how about return air ducting? Where is it located? Attic? Are your attic vents closed during the winter. Do you use a wood stove, pellet stove or fireplace? I think a good investigation is in order. I have seen candles cause this situation many times and customers just flat out refuse to beleive it. Anyway, answer these questions for more pondering. ;)

[maxair]

Your return sounds small to me.