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dr

Balboa Hot Tub

Severity: Moderate

Source: OnlyErrorCodes.com — Every error code. One place.

Balboa Hot Tub dr Error — Heater Dry Fire Warning

What Does This Error Mean?

'dr' on a Balboa control means the heater started but can't confirm there's water flowing through it.
This is the dry-fire protection — without water, the heater element burns out in seconds.
Stop and check the water level (should be above the highest jet), refill if low, then make sure the filter isn't clogged.
Most cases are simply low water from evaporation.

Affected Models

  • Balboa BP501
  • Balboa BP601
  • Balboa GS501Z
  • Balboa GS510DZ
  • Balboa VS501Z

Common Causes

  • Water level below jets — most common cause
  • Filter cartridge clogged with debris
  • Air lock in the heater after a refill
  • Pump losing prime
  • Failed flow switch or flow sensor

How to Fix It

  1. Check the water level.

    Lift the cover.
    Water should sit at least 1-2 inches above the highest jet.
    If lower, top up with a garden hose.
    Evaporation alone can drop the level several inches per week in summer.

  2. Inspect the filter.

    Remove the filter cartridge.
    Look for visible debris, leaves, or hair on the pleats.
    Hose it down with strong water.
    If saturated with oils or residue, replace it (filters are 25-50 USD).

  3. Bleed an air lock.

    If you recently refilled, an air bubble can sit in the heater housing.
    Loosen the small union nuts on either side of the heater (just a quarter turn) until water trickles out, then retighten.
    Restart and watch for 'dr' to clear.

  4. Check the pump is priming.

    Listen at the pump.
    You should hear water moving, not a high-pitched squeal (dry running) or silence.
    If silent or squealing, prime by pressing pump button on/off in 10-second intervals — air burps out.

  5. Test the flow switch.

    If water level, filter, and pump are all good, the flow switch may have failed.
    Open the equipment compartment and locate the flow switch (small device with two wires near the heater).
    This is replacement-level work — a service tech can confirm with a multimeter.

Frequently Asked Questions

How long can the spa run with 'dr' showing?

The heater is locked off when 'dr' shows — it's protecting itself.
Pumps still run, so the water won't damage anything.
But the spa won't reach temperature.
You can use it cold or fix the issue first.