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Hot tub dr and dry heater codes

Short answer

dr means the heater may be dry: not enough water in it or flowing through it to start safely. Balboa shuts the spa down for 15 minutes and tries again. After the third dr the panel shows the dry message (dy, drY or M027) and waits for you to clear it.

Updated By the HotTubFinder research desk

What to check first for a hot tub error code: for an overheat code, stay out and take the cover off; otherwise clean the filter, top up the water, open the valves and purge any air lock, reset the breaker once, then call a technician
What to check first for any code, in order, before you call a technician.

What you can check yourself

  1. Check the water level and top it up to the line in your manual.
  2. Purge an air lock the way your owner's manual describes.
  3. Clean the filter, or replace it if it is worn.
  4. Open any closed valves and jets.
  5. Clear the message on the panel once the cause is fixed.

Where the owner's part ends

Anything else: turn off power at the breaker and call a technician.

Heaters, pumps, sensors and the control board sit on mains power next to water. Never bypass a sensor, a pressure or flow switch, or a high-limit to get a tub running: they are what stop it from overheating.

What is the difference between dr and dry?

dr is the warning; dry is the lockout. Balboa's dr (M028) means the heater may be dry, so the spa shuts down for 15 minutes and then retries on its own. Its dry message (M027) means there is not enough water to start the heater at all, and the spa stays down until you clear it. On Balboa's VL panels the dry message appears on the third dr.

Every dry-heater code, system by system

9 codes
Every dry-heater code we recorded, by the system or manual that defines it
CodeWhat it meansWhat to do
M027Balboa, M codesPanel: The heater is dryThere is not enough water in the heater to start it, so the spa is shut down until the message is cleared.Check first
  • Check the water level and top it up to the line in your manual.
  • Clean the filter, or replace it if it is worn.
  • Open any closed valves and jets.
  • Purge an air lock the way your owner's manual describes.
  • Clear the message on the panel once the cause is fixed.

Call if it comes back after the checks.

M028Also: drBalboa, M codesPanel: The heater may be dryThe heater may be dry or short of water. The spa shuts down for 15 minutes, then tries again.Check first
  • Check the water level and top it up to the line in your manual.
  • Clean the filter, or replace it if it is worn.
  • Open any closed valves and jets.
  • Purge an air lock the way your owner's manual describes.

Call if it repeats after the checks.

drAlso: HTR MAY BE DRYBalboa panel lettersPanel: Heater may be dryPossible dry heater, poor flow or air bubbles in the heater. The spa shuts down for 15 minutes. Same fault as M028.Check first
  • Check the water level and top it up to the line in your manual.
  • Purge an air lock the way your owner's manual describes.
  • Clean the filter, or replace it if it is worn.
  • Open any closed valves and jets.

Call if it repeats after the checks.

Code 27Jacuzzi 2025 onPanel: Heater DryLow water flow; the heater is dry.Check first
  • Clean the filter, or replace it if it is worn.
  • Check the water level and top it up to the line in your manual.

Contact your dealer if it persists.

Code 28Jacuzzi 2025 onPanel: Heater Maybe DryLow water flow inside the heater; it may be dry.Check first
  • Clean the filter, or replace it if it is worn.

If the filter is already new, contact your dealer.

Code 27Sundance 880, 2025Panel: Heater DryThe heater is dry.Check first
  • Check the water level and top it up to the line in your manual.
  • Clean the filter, or replace it if it is worn.
  • Open any closed valves and jets.
  • Purge an air lock the way your owner's manual describes.
  • Clear the message on the panel once the cause is fixed.

Call if it returns after the checks.

Code 28Sundance 880, 2025Panel: Heater Maybe DryThe heater may be dry.Check first
  • Check the water level and top it up to the line in your manual.
  • Clean the filter, or replace it if it is worn.
  • Open any closed valves and jets.
  • Purge an air lock the way your owner's manual describes.

Call if it repeats.

drYAlso: dy, HTR DRYVita Spa 2026Panel: Heater is dryNo water reaching the heater; a closed valve or blocked suction, return, filter or skimmer.Check first
  • Check the water level and top it up to the line in your manual.
  • Open any closed valves and jets.
  • Clean the filter, or replace it if it is worn.

Contact your dealer if it persists.

drAlso: HTR MAY BE DRYVita Spa 2026Panel: Heater may be dryNot enough water reaching the heater.Check first
  • Check the water level and top it up to the line in your manual.
  • Open any closed valves and jets.
  • Clean the filter, or replace it if it is worn.

Contact your dealer if it persists.

Why does a hot tub heater read as dry?

The heater checks itself before it heats. Balboa runs the pump, fires the element for 6.5 to 18 seconds, then watches how far the temperature jumps. Water flowing past the element keeps the jump small; little or no water lets it spike, and the control calls it dry. Balboa calls this its dry-fire protection.

So the heater is usually fine. Low water, a closed valve, a clogged filter or air left in the plumbing after a refill keeps water out of it. Vita Spa's manual lists closed valves and blocked suctions, returns, filters or skimmers as the causes.

How do you clear a dr code?

Fix the water side, then clear it once. After a refill, use priming mode: Balboa gives you 4 minutes after power-up to run each pump and push the air out before the heater may start.

See what Pr and priming mode mean and how to start up a hot tub after a refill.

Common questions

What does dy mean on a hot tub?

The heater is dry. Vita Spa's 2026 manual shows the same fault as drY, dy or HTR DRY depending on the panel. The spa stays off until you fix the water supply to the heater and clear the message.

Why does my hot tub say dr after I refilled it?

Often trapped air: Balboa's VL panel guide lists air bubbles in the heater as one cause, next to low water and poor flow. Run each pump during priming mode to push the air out, or purge it the way your manual describes.

What does error code 27 or 28 mean?

On Balboa systems and the manuals that use Balboa's numbers, M027 (or Code 27) is heater dry and M028 (Code 28) is heater may be dry. Cal Spas, Marquis, PDC, Jacuzzi and Sundance print the same numbers.

Can I keep resetting a dr error?

Clear it once after checking the water level, filter, valves and air. If it comes back, stop resetting: the heater is not getting water and the cause needs a technician.

Sources

9
  1. Balboa TP400/TP600 user guide (40940_N), panel messages balboawater.com · checked October 2026
  2. Jacuzzi J5 owner's manual (rev A) links.imagerelay.com · checked October 2026
  3. Sundance Spas 880 Series owner's manual, 2025 (rev E) links.imagerelay.com · checked October 2026
  4. Vita Spa owner's manual, 2026 res.cloudinary.com · checked October 2026
  5. Balboa VL401 user guide (40789_G), diagnostic messages balboawater.com · checked October 2026
  6. Balboa troubleshooting and service manual for EL/VS systems balboawater.com · checked October 2026
  7. Cal Spas Patio and Patio Plus owner's manual, Balboa equipment, 2026 calspas.com · checked October 2026
  8. Marquis Crown Collection owner's manual, 2026 marquisspas.com · checked October 2026
  9. PDC Spas hot tub owner's manual, 2026 media.cmsmax.cloud · checked October 2026

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