High Limit Switch used in many gas & electric heaters. Common on some Hurlcon & Astralpool heaters. Failed hi limits cause the F2 Errors found on Hurlcon and Astral Gas Heaters. AKA Thermal Cutout
Used on Outlet for some early Hurlcon & Purex Minimax heaters. Never used in any plastic headers. Automatic Reset. On early Hurlcon HX heaters, the high limit switch had a blue plastic body secured with 2x philips head screws onto a small copper plate brazed onto the heat exchanger outlet elbow. Some newer ones are threaded.
- These are an Extremely Important Safety feature found on heaters. They must be replaced when necessary.
- When installing, make sure both male & female thread are clean. We recommend lightly lubricating the thread, and *gently* screwing them in, as the thread shaft is thin brass. Dirty threads, or over-tightening can break the shaft.
May also be found on JX 130 and JX 160 gas heaters.
Hurlcon Part Number 71032 - Threaded / 71018H - Non Threaded
Purex Pentair Part Number 071017
Other High Limit (Hi Limit) Switches:
42-45C° Inlet Hi Limit (Hurlcon, Astralpool, Raypak, Pentair)
52-55C° Outlet Hi Limit (Hurlcon, Astralpool, Raypak, Pentair)
60C° Outlet Hi Limit AGS (Hurlcon, Astralpool, Raypak, Pentair)
70C° Outlet Hi Limit (Hurlcon, Astralpool)
175C° Flue Temp Sensor (Hurlcon, Astralpool)
Hurlcon / Astralpool HiLimit Locator Brass Threaded Plug