HAXBPK1931
Bypass Service Parts Kit
(for heater models with fin-tube type heat exchangers)
IMPORTANT NOTE
This kit is intended to be used with Hayward gas heater models which utilize fin-tube type heat exchangers manufactured after
December 1996. Fin-tube heat exchangers can be identified by the existence of two plastic headers (one on either end of the
heat exchanger), or by the date of heater manufacture. Fin-tube heat exchangers were used in heaters manufactured
through October 2000. The table below may be used to extract the date of heater manufacture based on heater serial number.
Serial Number Format | Year (Y) | Month (M) |
| 2ymxxxxx | 7=1997 9=1999
8=1998 0=2000 | A=Jan D=Apr G=Jul J=Oct
B=Feb E=May H=Aug K=Nov
C=Mar F=Jun l=Sep L=Dec |
| 00mxxxxx | 2000 | B=Feb D=Apr F=Jun
C=Mar E=May G=Jul |
| ymmxxxxx | 0=2000
1=2001 3=2003
2=2002 4=2004 | 01=Jan 04=Apr 07=Jul 10=Oct
02=Feb 05=May 08=Aug 11=Nov
03=Mar 06=Jun 09=Sep 12=Dec |
| 21130ymm1xxxxx001 | 5=2005 7=2007
6=2006 8=2008
| 01=Jan 04=Apr 07=Jul 10=Oct
02=Feb 05=May 08=Aug 11=Nov
03=Mar 06=Jun 09=Sep 12=Dec |
INSTALLATION PROCEDURE
1. Turn pump, main gas valve, and heater power off.
2. Remove drain plug and drain water out of heat exchanger.
3. Remove screws from access panels around inlet/outlet
header and remove panels.
4. Remove wires from high limit switches on header.
5. Millivolt Heaters Only: Remove the thermostat bulb from the
header. Note: Using needle nose pliers to pull out copper
strip makes bulb removal easier.
6. Electronic Heaters Only: Unplug thermistor wire lead from
control board.
7. Remove pressure switch tube from header.
8. Loosen union nuts and detach pool plumbing from header.
9. Remove (12) nuts from the header.
10. Remove the header and header o-
ring from the heat exchanger.
11. The bypass adapter, shaft, and
spring are removed by unscrewing
the adapter as shown in the
illustration.
12. Remove the bypass insert and
valve disk from the header as
shown in the illustration.
13. Replace parts as necessary with
the new ones in this kit. It is
recommended than all parts be
replaced at the same time.
14. Inspect and ensure valve disk
slides freely on the shaft.
15. Re-install by reversing the above
procedure. Install the new header
o-ring when re-installing the
header to the heat exchanger.
Parts List
Item
Number
| Description
| Quantity |
| 1 | Bypass Baffle
| 1 |
| 2 | Header O-Ring
| 1 |
| 3 | Valve Spring
| 1 |
| 4 | Valve Shaft (Brass)
| 1 |
| 5 | Valve Disk (Brass) | 1 |
| 6 | Bypass Adapter (Brass) | 1 |
