Rheem 400 series thermostat problem

[hdb454]

i have a 5 year old rheem 18 seer heat pump with a rheem 400 series thermostat
recently the thermostat show the indoor temperature at 56 deg and the room temp is 74 deg service contractor replaced thermostat and it still does not work checked temp at thermostat with mercury therm it shows 74 deg so the thermostat is not working properly could it be a wiring issue as we did have a rodent problem a year or so ago and could the problem just showing up now or did i just get a bad replacement thermostat any help would be appreciated the thermostat had been working good until now

[kdean1]

I can't make sense of one long sentence without punctuation and capitalization. I don't want to take the time to decipher it.

[hdb454]

I am probably lucky

[BaldLoonie]

Cold air in the wall behind the stat?

[hdb454]

Thank you for your help we will check that out

[hdb454]

We checked the wall temp it was room temperature .The thermostat is mounted aprox 3' above the cold air return .

[stvc]

If the stud cavity is the return duct it could also be pulling cold air from the outside somehow.

[hdb454]

Thanks i will see if i can determine that, Again thanks for your help greatly appreciated