I had used Noll for several years for servicing furnaces in rental properties I own but my most recent experience with them will be my last.
I had them in to do a routine servicing of my Carrier furnace and the technician detected a carbon monoxide leak. He was unable to determine the source of it and arranged to return for more extensive testing. On the second occasion, he was still unable to determine the cause and decided that the heat exchanger must be at fault and needed to be replaced. As an alternative, I could consider replacing the whole furnace, as it would not be much more than replacing the heat exchanger, since to do so would require dismantling most of the furnace.
At a follow-up meeting with a sales rep., I was told that it would require a full day of technician time to remove the heat exchanger and then to send it to Carrier for them to determine if it was covered under warranty would take a week or more. Meanwhile, the house would be without heat. I was quoted $3477 for a single-stage furnace and $4002 for a 2-stage unit.
I contacted Carrier and confirmed that Noll is not, in fact, an authorized dealer. They confirmed that the furnace was still under warranty and that if the heat exchanger proved to be at fault, it would be replaced for only a partial labour cost. They recommended I get a second opinion from an authorized Carrier dealer, which I did. The other company had a replacement heat exchanger on hand when the technician came and it only cost me 2 hours of labour for the whole job!
I went back to Noll to ask for an explanation and was told that "Carrier is really hard for us to deal with" and when a heat exchanger goes, they usually try to sell a new furnace. When I asked why they would say it would take a full day to remove and replace a heat exchanger when another company did it in only a few hours, the reply was, "Wow, those guys must be really good." There was no offer of a refund or compensation.
See the screen capture from Noll's web site in which they claim to be an authorized Carrier dealer.
Noll has lost my business.