Heat Exchanger Assembly for Hayward FD350 Heater FDXLHXA1350

Heat Exchanger Replacement Procedure

Heat Exchanger Service Parts Kits
for Universal H-Series (Forced-Draft) Heaters

IMPORTANT NOTES:

REPLACEMENT PROCEDURE

1. Tum pump, main as valve, and heater power off.
2. Remove drain plug and drain water out of heat
   exchanger.
3. If necessary, disconnect header union fittings from
   swimming pool/spa piping.
4. Pull temperature limit switch wires through the
   grommet on the heater side panel. and disconnect limit
   switch wires from heater wire hamess.
5. Remove screws and remove both of the upper plastic heater side panels (see Figure 1 for screw locations,
   and Figure 2 for part locationhdentification).
6. Disconnect the 2 wires from the pressure switch. which
   is located on the inletloutlet header.
7. Remove countersunk screws on heater top and
   remove louvered exhaust panel on heater top (see
   Figure 2).
8. Remove the heater top tlue cover by removing 3
   screws on each side of the heater (see Figure 2).
9. Remove screws and remove rain shield assembly (see
   Figure 2). Note that there are screws which hold the
   rain shield assembly to the heat exchanger tube
   sheets, which also must be removed.
10. Remove the front access panel and the control box
    cover (see Figure 2).
11. Disconnect the temperature sensor plug from the
    circuit board located inside the control box.
12. Pull the temperature sensor wires out of the control
    box and through the hole in the heater cabinet.
13. Carefully lift the heat exchanger up and out of the
    heater cabinet.
14. Before installing the new heat exchanger assembly,
    install the new adhesive-backed gaskets (included in
    this kit) onto both ,of the new heat exchanger tube
    sheets.
15. Install the new heat exchanger assembly. Ensure the
    heat exchanger is properly oriented with the arrows on
    the tube sheet decal pointing up.
    CAUTION: Do not install heat exchanger upside
    down. Heat exchanger is labeled to indicate the
    proper orientation. The heat exchanger will be
    damaged if installed incorrectly.
16. Remove the pressure switch from the old heat
    exchanger assembly and install on the new heat
    exchanger assembly. Apply pipe thread sealant to the
    pressure switch threads before assembly.
17. Reverse the above steps to reassemble the heater.
18. Activate water pump and check the system for leaks.