DIY Error Codes

Hayward Universal H-Series gas pool heater Error bD

Gas valve or control board fault. Some bD conditions reset on their own; others stay locked out.

Note the code. Some bD conditions reset on their own; others stay locked out. If bD comes back, call a qualified pool heater technician.

Start the fix →When to call a pro ↓
Full answer & models

Hayward bD on a Universal H-Series heater means gas valve or control board fault. If it keeps returning, Hayward says to contact a qualified service company.

Applies to: H150FDH200FDH250FDH300FDH350FDH400FDH500FD
Also searched as: Hayward heater error BD, Hayward H-Series bD code, Hayward heater b d

Gas appliance. Service only by a qualified technician; power off before any service.
Why
Hayward, what to do if you smell gas: do not try to light any appliance; do not touch any electrical switch and do not use any phone in your building; immediately call your gas supplier from a neighbor's phone and follow their instructions; if you cannot reach your gas supplier, call the fire department. Installation and service must be performed by a qualified installer, service agency, or the gas supplier. Hayward: before installing or servicing this electrical equipment, turn the power supply off. Hazardous voltage can shock, burn, cause death or serious property damage.

What bD means

Gas valve or control board fault. Some bD conditions reset on their own; others stay locked out.

More detail
Hayward's Universal H-Series owner's manual (Figure 4, Error Codes) lists bD as "Internal fault / gas valve sensing / data retrieval error": Hayward lists several bD conditions: an internal fault or power-up error (resets immediately once the gas valve relay check is acceptable); gas valve sensed ON when it should be off (lockout, automatic restart 2 minutes after correction); gas valve sensed OFF while flame is sensed (lockout after 10 occurrences, automatic reset 60 minutes); and a data retrieval error (control input data corrupted, heater shuts down and locks out). The manual's instruction for error codes is to contact a qualified service company for assistance.

5-minute checks

Fix it step by step

Step 1 of 2

  1. Note the code and wait

    • 2 min
    • None
    • DIY

    Safety: Gas appliance. Service only by a qualified technician; power off before any service.

    Depending on the condition, reset is immediate, 2 minutes, or 60 minutes; a data retrieval error stays in lockout.

    More detail

    Note the code and wait.

    Write down the code and when it appears. Per Hayward's Figure 4: Depending on the condition, reset is immediate, 2 minutes, or 60 minutes; a data retrieval error stays in lockout.

    Did the code clear?

  2. Call a qualified service company

    • Decision
    • None
    • Pro decision

    Stop here and book a qualified technician.

    More detail

    Call a qualified service company.

    Hayward's owner's manual says to contact a qualified service company for assistance with error codes. Installation and service must be done by a qualified installer, service agency, or the gas supplier. Do not open the heater cabinet yourself.

    Still showing bD?Need a pro → call a pro

Code cleared. Nice work.

Watch the display for a day to make sure it stays clear.

Back to top

Fixed after any step? Watch the display for a day to make sure it stays clear. Still bD after step 2? call a pro.

Call a pro if…

  • You smell gas (leave first, then call your gas supplier from a neighbor's phone).
  • bD keeps coming back or the heater stays in lockout.
  • Anything that needs the heater cabinet opened or wiring checked.

FAQ

What does Hayward heater code bD mean?

"Internal fault / gas valve sensing / data retrieval error", per Figure 4 of the Universal H-Series owner's manual. Hayward lists several bD conditions: an internal fault or power-up error (resets immediately once the gas valve relay check is acceptable); gas valve sensed ON when it should be off (lockout, automatic restart 2 minutes after correction); gas valve sensed OFF while flame is sensed (lockout after 10 occurrences, automatic reset 60 minutes); and a data retrieval error (control input data corrupted, heater shuts down and locks out).

What does Hayward say to do about bD?

Contact a qualified service company for assistance, per the manual's error-code section.

Source: Hayward Universal H-Series Owner's Manual (H150FD-H500FD), Figure 4 Error Codes, pp. 13-14; safety, pp. 1 and 3. Written by the DIY Error Codes team. Updated 2026-10-16. DIY Error Codes is independent and not affiliated with or endorsed by Hayward.