Display shows 'PS' and heater will not fire; blower or pump may run briefly then stop.

Safety first: Turn off power to the heater before opening panels. Ensure pump cannot start unexpectedly.

Steps to address PS error:

• Verify pump operation: Confirm the pool pump is running and fully primed. Check for air in the pump basket and correct any suction leaks.
• Clean filtration system: Backwash sand/DE filters or clean cartridge filters. Dirty filters reduce flow and can open the pressure switch.
• Check valves and bypass: Ensure all valves to and from the heater are fully open. If there is a heater bypass, confirm it is not diverting most of the flow away from the heater.
• Inspect pressure switch tubing: Locate the water pressure switch on the header and inspect any small tubing or port feeding it. Clear debris or scale from the port using a small brush or wire with the system depressurized.
• Adjust pressure switch (if adjustable): Some Raypak pressure switches have an adjustment screw. With pump running and adequate flow, slowly adjust until the heater recognizes flow and the PS error clears, following Raypak’s specifications.
• Test/replace switch: With power OFF, disconnect the switch leads and check continuity with pump running (you may need a helper). If the switch remains open under good flow, replace it with a Raypak‑approved pressure switch.

Note: Never defeat or permanently jumper the pressure switch; it is a critical safety device.