1st some background (sorry about the length): In Feb 06 we added 2 new Carrier Infinity Systems to our house (2 furnaces, 2 compressors, etc.). On the other side of the house (it’s a big old Victorian) we already had 2 carrier systems (installed April 04, Thermidistat thermostat) (1 w/ 2 zones) that included the Infinity 96 furnaces, variable-speed blowers, and 2 compressors (I think the comfort line as they’re NOT the 2 speed ones). When adding the new systems 3 years ago we made the older, existing systems into Infinity systems (Infinitized them. Everything worked great for the 3 or so years until a couple of weeks ago.
The “Infinitized” system w/ 2 zones (1 zone is the entire 3rd floor which almost NEVER calls for heat or cooling as we don’t use the 3rd floor, the other zone is 3 bedrooms & 2 baths on the 2nd floor, the stat’s in the master) got a system fault or something to that effect. I was able to press a button to dismiss it & thought nothing of it. But it came back again a couple of days later so I went into the “service” mode on the Infinity stat & discovered the following errors: 25 – Model/Setup error (87 events); 45 – Control Lockout (17 events), this one (45) also stated Active on this occasion. I check the service checkout daily and notice these 2 errors all the time. There are some others on occasion (41 & 32).
Here’s what else I noticed: when the stat calls for heat it comes on full blast (sounds like a freight train), stays on for a couple of minutes, shuts off, than seems to purge its self on full blast again for a minute or so. It also tends to overshoot now by 1 degree. It’s as though there’s no slow speed when it calls for heat. Before this fault you barely noticed the system was on, just like all the other ones in the house. This particular stat is in the master bedroom so you really notice the air blasts. I also noticed that the manual fan speed (L,M, & H) blow much stronger & are much louder than before. In fact, you would have been hard-pressed to figure out which manual fan speed it was on. The Infinity system made this thing pretty unobtrusive for those 3 years. One final thing – before we Infinitized this, it was certainly more obtrusive than after the Infinitizing, but not as bad as it is now – the manual fan speeds (using the Carrier Thermidistat) were stronger & louder & the system came on strong AT TIMES, but not all the time. I even tried changing the Zone Airflow Limits to the following:
Zone 1 (the smaller zone where the main stat is): from Maximum to Low - kept Zone 2 (the larger 3rd floor zone) at Medium. This solved the manual fan issue to some degree (back to being slower & quieter, though I’m unsure if it’s as quiet as it was), but everything else is still the same-loud, strong, obtrusive. I also tried changing the Furnace Airflow to Comfort from Efficiency with no effect. Can anyone shed some light on what the problem(s) may be? I can supply you with more info if necessary. Thx.
58MVP100-F Natural Gas furnace
CK5BXA048021 - coil
38TXA048331 - condensor
Carrier Zoning panel