It’s the big moment of spring—the day when the temperature outside is finally hot enough that you need to have your heat pump change over from heating mode to a cooling mode for the first time this year. You step up to the wall thermostat, make an adjustment to lower the indoor temperature to cooler than the outdoor temperature. You listen for the heat pump to kick on. The fans start up, air comes from the vents…
…but the air either doesn’t get cool enough, remaining at room temperature, or it comes out warm.
Obviously, you don’t want a heat pump that only does half of its job, and you need to have cool air circulating through the house. What’s wrong with the heat pump, and what can be done about it?
First, make a few basic checks
Don’t leap to the immediate conclusion that the heat pump has a serious malfunction. The problem may be a simple one. Look over the thermostat again and make sure all the settings necessary for the heat pump to switch over to cooling mode are correct. Take out the air filter from the HVAC cabinet to see if it is thickly clogged up. If it is, put in a fresh one. (Clogged filters often cause a drop in cooling ability because they strangle airflow through the system.) Examine the outside cabinet to make sure nothing is obstructing it. If the fan didn’t come on at all, open up your home’s electrical panel to find out if the circuit breaker to the heat pump tripped.
The broken reversing valve
If you haven’t been able to find a basic cause for the heat pump not switching to cooling mode, call for an Ankeny, IA, HVAC contractor to come to your house and find out what’s wrong. There are a number of malfunctions that can lead to a heat pump refusing to change to cooling mode, and one of the most common is a broken reversing valve. This valve is the component responsible for changing the direction refrigerant moves through the heat pump, and that determines if the heat pump is in heating or cooling mode. If the valve becomes stuck or doesn’t respond to the thermostat, the heat pump will remain frozen in one mode. Technicians can either fix the reversing valve or replace it to repair the problem.
Sometimes the thermostat controls are what is causing the heat pump to refuse to change to cooling. The temperature sensors in the thermostat may become miscalibrated so they sense the temperature in the house is cooler than it actually is so it won’t turn to the cooling mode when it should. Thermostats can also lose their connection to the reversing valve, the compressor, or the blower fan—each component has a different thermostat wire to control it. An HVAC professional can diagnose if the thermostat is at fault and take care of repairing it or recalibrating it.
At Golden Rule Plumbing, Heating & Cooling, “We Obey the Rules to Live By!”
Call us anytime when you need a heat pump or AC repair.