Balboa · BP series (TP400, TP600, TP800, TP900, spaTouch panels)Stop using the tub

HTR DRY on a Balboa hot tub: heater is dry

There is not enough water in the heater to start it, and the spa has shut down. Do not run the tub until the water level and flow are restored, then press a button to reset.

Also shown as: M027, dry, The heater is dry

Most likely causes

  1. 1Water level too lowmost likely
  2. 2Air lock in the pump or heatercommon
  3. 3Blocked filter or closed valvecommon
  4. 4Pump failureless common

What to try, in order

  1. Fill the tub to the correct level.
  2. Turn off power at the breaker, clean the filter, and check that slice valves are fully open.
  3. Restore power and bleed air from the pump until water flows strongly from the jets.
  4. Press any button to reset the message.
  5. If no water moves, switch the tub off at the breaker and call for service.

HTR DRY questions

What does M027 mean?

M027 is the Balboa BP code for a dry heater. The spa stays shut down until you restore flow and reset it.

Will HTR DRY damage the heater?

The message is the protection working. Damage happens when a heater actually runs without water, so fix the flow before resetting.

Related codes

Balboa -- · Temperature not yet knownBalboa CHEK PH · Maintenance reminderBalboa CLN FLTR · Filter reminderBalboa CNFG FAIL · Configuration errorBalboa dr · Heater may be dryBalboa dry · Heater is dryBalboa Ecn · Economy modeBalboa FLO · Low water flow

General guidance. Follow your manufacturer's instructions; anything inside the control box is work for a licensed professional. Updated October 5, 2026.