Runs Too Much
RUNS TOO MUCH - The system maintains the correct temperature at the thermostat, but either does not shut off or seems to run too much.
POSSIBLE PROBLEM & DESCRIPTION
Thermostat "Fan" Switch
This problem could be caused by the “Fan” switch on the thermostat. It normally has two options – “Auto” and “On”. In the “Auto” position, the fan should cycle on only when there is a call for cooling. In the “On” position, the fan will run continuously. Watch Video.
Some new thermostats have an additional fan setting of “Circ”, which is short for “Circulate”. In this mode the fan will cycle on and off with the cooling, but it will also kick-on automatically if there is an extended period without a demand for cooling – to provide additional air circulation.
If your system has an added humidifier, this could cause the system to run more than normal.
Some humidification system energize the blower to operate even when the heating system is not running to maintain the humidity setpoint in the space.
Clogged Air Filter/Dirty Coil/Restricted Ductwork
All new York air handlers have a feature which disables the auxiliary heaters if the over-temperature device is activated three times during a run cycle. This "lock-out" also energizes the fan to run continuous until manually reset.
The most common cause of this failure is low airflow across the heaters. The most common source of low airflow is a clogged air filter, but can also be caused by a dirty indoor coil or closed/restricted ductwork.
Once the source of the airflow restriction is eliminated, reset the lock-out by cycling high-voltage power to the air handler.
Supply Duct Issues
If there are specific registers that produce very little or no airflow (while others seem sufficient), this would likely indicate either restricted or disconnected supply ducts.
Return Ductwork Issues
If the return duct system has openings or has come loose (especially in an unheated attic or crawlspace), it will draw-in cold air and, even if the heat pump is operating normally, blow cool air from the supply registers and may not heat the space. This condition is easiest identified by checking the return air temperature entering the air handler. An extremely cool return air temperature would indicate ductwork problems.
This problem may show itself only during extremely cold outdoor air conditions.
Heat Pump Lockout - Qualified Technician Recommended
Some York heat pumps incorporate a YorkGuard module which monitors equipment operation. If the Yorkguard senses an abnormal condition which could possibly harm the system it will enter a lock-out mode which disables the heat pump.
If wired-in, the Yorkguard should give an alert indication at the thermostat.
A lock-out can be reset by turning the thermostat to the "Off" position and then back to "Heat" or "Auto".