Thermostat acting up

[3rdgendslmech]

So yesterday after it warmed up a little bit low 50s I noticed that my house (heat pump system) was running a little longer than usual to warm up the house. I've got a honeywell programmable thermostat and at first I just figured it kicked over from 63 to 65. So I was down in my shed changing the oil in my truck and after about an hour I noticed that the outside unit hadnt shut off at all since I had been down there.
So I come in the house and the inside temp says 65, it feels 65 possibly warmer. So i watch for another 10 -15 minutes and it still doesn't shut off. So for about an hour and a half its running. I bump the temp down to 63 and it shuts off, but a few moments later the inside temp jumps up to 67.
This morning I woke up and it was doing the same thing but set at 63. I got downstairs, inside temp is 63.....40 minutes later inside temp is still 63 and heat pump is still running. So just for S&Gs I change the batteries in the thermostat, put it back on and the temp reads 67 again.

Is it pretty safe to say that the thermostat is failing?

 

[pioneer1]

There are led lights on the circuit board of the furnace that will flash a code to tell you what is / if anything is wrong. The code is explained in your manual or it will be on a sticker on the furnace access door.

 

[Done That]

I might set the thermostat to just hold a single set point, no setbacks, and observe operation.

Many possibilities like outdoor unit a bit low on charge, not defrosting properly etc that could be contributing to unit not keeping up.

 

[3rdgendslmech]

Seems to be doing fine now since i've changed the batteries. Temp is set at 64...currently 55 outside. It'll start and run for about 5-10 minutes then shut off for about 40-50 minutes. I'm gonna go to lowes and pick up a thermostat just to have on hand and see what happens the next few days. It's supposed to cool down after Xmas eve.
Meanwhile I'm gonna go out and get some information off of the run start capacitor and the contact switch and maybe do a little tune up before I get caught with my pants down.

 

[3rdgendslmech]

There are led lights on the circuit board of the furnace that will flash a code to tell you what is / if anything is wrong. The code is explained in your manual or it will be on a sticker on the furnace access door.

I dont know about the outside unit, it's newer (2010) I think but the air handler inside is the original from 84' so i doubt the inside unit has blink codes. Never hurts to look though. Like I said the house is heating up just fine so I dont think its anything with the compressor or the handler.