Diagnostic guide
Heat pump runs constantly? Here is what is happening and what to do.
A heat pump that runs constantly is either undersized for the load, has lost refrigerant, has a dirty coil that's reducing efficiency, or is fighting a poorly insulated space. In Vermont, dirty coils are the most common fixable cause we encounter.
Likely causes, ranked by probability
- 1
Dirty coil reducing efficiency
System runs longer to reach setpoint.
Likelihood 35%
- 2
Low refrigerant
Reduced capacity means longer run times.
Likelihood 25%
- 3
Undersized system or poor insulation
System can't keep up with the load.
Likelihood 25%
- 4
Aggressive thermostat setpoint
Very low cooling or very high heating setpoints.
Likelihood 15%
What you can try first
- · Wash the filter
- · Rinse the outdoor coil
- · Raise heating setpoint or lower cooling setpoint by 2-3 degrees
When to call us: Cleaning and setpoint adjustments don't reduce runtime within a week.
Our diagnostic process
We arrive within a one-hour window, inspect the system end-to-end, read any active error codes, test temperatures and pressures, and identify the actual cause. You get a written quote before any repair work starts. The $129 diagnostic fee is applied to any repair you proceed with.
Frequently asked questions
Is heat pump runs constantly dangerous?
Most causes of "heat pump runs constantly" are not immediately dangerous, but ignoring them can damage the system or raise repair cost. Cleaning and setpoint adjustments don't reduce runtime within a week.
Can a cleaning fix this?
Sometimes. Biofilm, dirty coils, and clogged drain lines often resolve after a deep clean. Mechanical or electrical issues require a diagnostic visit instead.
How much does diagnosis cost?
Our diagnostic visit is $129 flat, applied to any repair you proceed with. We will quote any repair before starting work.
Need a tech to take a look?
$129 flat diagnostic. Same-week scheduling across Vermont. Credited toward any repair.