HVAC Question

[exploder3211]

Ok, My heats been on the fritz scince the begining of this cold snap. Its a Carrier unit with A/C model 40A0018330CD (inside unit).. How do i tell if its a heat pump besides listning?? I have tried this and we've heard nothing, the out side units are below our windows and we never hear them in heat mode and we only hear one when it's a/c season. Second, my stupid furncace runs and runs and never shuts off with the thermostat. Even when you cut it off manually it doesn't shut off for like three or four minuets. I am thinking they keep installing the wrong kind of thermostat, as the heat did work before the first time it broke in a/c mode (it wouldn't hold anything more than 75 degrees on here)The replace the T-stat then.. Help??????? I am waiting on the mantince people now.. Ughhh...

 

[rp2813]

I think the fans on all forced air furnaces continue to run for about a minute or two after the themostat has reached the desired temperature or has been manually turned down. This is to get all of the heated air out into the living space even after the burners have shut off. If the actual burners aren't shutting down after you turn off the thermostat then there's definitely a problem. If you pull the thermostat off the wall and just touch the two wires together to run it, you can determine that way if there's a problem with the thermostat. Any decent maintenance person should be able to figure this out.

I did have a problem with my furnace once when the circuit board in the furnace was shorting out. The furnace would either shut down before it reached the desired temperature, or sometimes the burner would shut down but not the fan. The circuit board was replaced and I've never had another problem.

My partner's parents have a heat pump/ac unit. IIRC, it doesn't matter if it's heating or cooling, the thing still makes a racket regardless.

Ralph

 

[whirlcool]

The fan motor running and running could be a defective fan module. If you installed the thermostat without turning off the power to the furnace from the circuit box it could have blown this module.
We have the same problem with our heater, but only when it gets below 28 F. The fan motor runs and runs and starts blowing cold air around. When you shut the system off at the thermostat it takes about 5 minutes for the fan to stop blowing. We have identified it as a blown fan module, but the company that makes it is no longer in business. And this house is only 12 years old! So since it doesn't get below 28 F very often we just live with it. We may not be here much longer, so we don't want to install a new furnace when this one is in great shape.

 

[exploder3211]

Thanks.. LoL.. Our's is an Electric Heater w/ a/c coil unit. The apartment complex had the hvac people out today finally. They replaced a wire going from the thermostat to the furnace and insalled a remanufactured control bord. Apperently the smaller heating systems like ours are a big pain to replace and are more costly to replace than a bigger system. I can see why as they told me that the duct work would need to be replaced as well (apperantly the 20 year old system we have is incapable of handling the airflow of the newer systems),,