HVAC Doc!!

wolfcub

Quick question related to my other thread.

Someting I have noticed is that I have my set point at 77 degrees and last night when I came upstaird to go to bed the unit was running and the tempreture was 75 degrees. Is this simply a result of the inaccuracy of the contractor grade Honeywell thermostats used or is an indication of something else?

FYI - I have had the same thing happen with TWO different thermostats, both the Honeywell T8411R.

Thanks

HVAC Doc

Did you measure per chance what the actual temp. was at the stat? Was it really 75 deg. or was it warmer/cooler? Could also be the spread that is programmed into the stat is too high. Some stats allow you to adjust it to overrun a certain number of degrees. An overrun of deg. in heat is acceptable but in cooling, that isn't a common point. Something is definately off/misadjusted/not working correctly.

wolfcub

FOrgot to mention that. I have a manual thermometer next to the stat and it was reading 75 degrees. This stat I have is non-programmable and says that it is set for 3 CPH

HVAC Doc

Ok if it was reading 75 and was set for 77 and the CPH is set at three, it means it would have ran till it reached 74 and then shut down.

wolfcub

REALLY!!! I thought it is supposed to shut off where it is set. The one we have downstairs comes on and then shuts off at a reading of 78 where we have it set.

HVAC Doc

BAH I must have had my head up my $$$ yesterday. NM my response as I had differential on the brain not CPH ( Cycles Per Hour). The cycles per hour would have no effect on what you are talking about. Adjustable temp. differentials would. Sorry about that, sometimes when you have one thing on your mind, the brain just fills in what you are reading. Sounds though like you do have some issues with the stat if you are indeed getting the same reading for actual temp. More than likely, a cooling anticipator is bad (a little resistor built into the stat) and not shutting off properly. If I remember correctly, that model of stat is a fixed type (non adjustable temp. differential).