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Heater Errors (DR / DRY / HTR)

Heater Error Diagnostics (DR / DRY / HTR Codes)

Heater error codes such as DR, DRY, and HTR occur when the spa control system detects that the heater is not operating under safe conditions. In most cases, these errors indicate that water is not moving properly through the heater, which can cause the heater element to overheat.

Many spa systems will automatically shut down the heater when these errors occur to prevent damage to the heater element or plumbing.

Before replacing expensive components, it is important to properly diagnose the spa system.

Common Causes of Heater Errors

The most common causes of DR, DRY, or HTR errors include:

• Dirty or clogged filters
  • Circulation pump failure
  • Air lock in the plumbing after refilling the spa
  • Restricted water flow through the heater
  • Flow switch or pressure switch problems
  • Temperature sensor issues
  • Heater relay stuck closed on the control board

Circulation Pump Problems

Many modern spas use a small circulation pump to constantly move water through the heater and filtration system. If the circulation pump stops working or becomes restricted, the heater may shut down and produce a DR or DRY error.

Signs of a circulation pump problem include:

• Spa not heating
  • No water movement from circulation return
  • Pump humming but not moving water
  • Repeated heater shutdowns

Air Lock After Draining

After draining and refilling a hot tub, air can sometimes become trapped in the plumbing lines. This can prevent water from flowing through the heater.

In many cases, simply loosening the pump union slightly to release trapped air will restore normal water flow.

Heater Element Problems

If water flow is normal and the heater still does not work, the heater element itself may be failed. Heater elements can burn out over time and may need to be replaced.

This is a simple continuity test. Using your meter check across the two terminals of the heater for continuity. The reading does not matter if there is continuity; the element is good.

The two things that can happen to the element itself is being open meaning no continuity or causing a GFCI Breaker trip. Other than that there are no other failures meaning if you do not have either of these two issues the element is not the cause. 

Control Board Problems

Another possible cause of heater errors is a stuck heater relay on the control board. When a relay fails to open, it may prevent the heater from turning off causing it to operate incorrectly.. Inversely if the relay does not close it can cause the heater not to heat. 

Diagnose Before Replacing Parts

Heater errors are often caused by flow problems rather than a failed heater.

Always check filters, pumps, plumbing restrictions, and wiring before replacing parts.

Note: If you ever remove the filters to clean them, power down first. If you don’t and there are any items floating in the tub they can be pulled into the front suction side of the pump. I have seen many things pulled into the pumps like bikini bottoms and more.

Proper diagnosis will save time and prevent replacing components that are still working.

Call for basic support or parts help or Text pictures for part identification.

Call 1-866-829-3660 or Text Parts Pics to 772-800-5445 Know Before You Go.