Master Temp 400 HLS

[lc7118]

I've had my master temp 400 since 2017 and it seems like I'm replacing sensors and part on it annually.

Currently its turns on, heats for about a minute, then shuts off for a minute, then starts on again, and repeats this endlessly.

Its showing a HLS error, so I replaced the HLS and ACG sensors but the same problem persists.

If I jump the HLS wires it stays on with no problem.

I replaced the thermal regulator just last year.

What else might be causing this?

Is there any danger in leaving the wires jump until I fix the root cause?

 

[ajw22]

.

I replaced the thermal regulator just last year.

The High Limit Switch prevents the Heat Exchanger outlet temperature from exceeding 135°F (±8°F).

The HLS is often caused by lack of sufficient water flow through the heat exchanger. This can be due to several things:

• Thermal regulator not opening.
• External bypass open.
• Internal bypass broken.
• Pump too small or on too low rpm.
• Clogged filter.
• Scale in heat exchanger.

Is there any danger in leaving the wires jump until I fix the root cause?

Yes, the heater is internally overheating and you will further damage it running with the HLS sensor bypassed. The HLS sensor is doing its job.

Check that the thermal regulator is opening at 120F in a pot of water.

Pentair MasterTemp Heaters - Further Reading

www.troublefreepool.com