Why Is My Pool Heater Not Heating the Water Enough
If your pool water stays lukewarm no matter how long the heater runs, the cause is usually not what homeowners expect first.
Scale Buildup Is the Number One Cause in San Antonio
A gas pool heater pushes pool water through a heat exchanger to warm it, and San Antonio’s water hardness, reported by SAWS at 15 to 21 grains per gallon, deposits scale inside that exchanger the same way it scales up a household water heater tank. Once the exchanger is coated, heat transfer drops significantly even though the burner itself is working fine.
Incorrect Thermostat Settings
Sometimes the simplest explanation is correct, the set point is lower than expected or a control has been bumped. Worth checking before assuming a mechanical fault.
Heat Pump Refrigerant or Compressor Issues
For heat pump pool heaters, insufficient heating often points to a refrigerant or compressor problem rather than scale, since these units do not have the same exchanger vulnerability as gas heaters. This requires a professional diagnosis rather than a simple flush.
Undersized Heater for Pool Volume
If the heater has never adequately heated the pool, even when new, it may simply be undersized for the pool’s actual water volume, an installation issue rather than a repair one.
Pool not heating right? Call (877) 560-1148 for a diagnosis.