LAARS LX400N-L - HI LIM SW Error - Replaced Switches and Harness

[garywi]

Hi Guys, my heater will run for 15 minutes and then throw the HI LIM SW Error. I replaced the High Limit Switches twice and also just replaced the harness and still same problem.

I don't seem to have a flow problem. Filters are clean. Everything else on the pool is working.

Thoughts on where to go next with this one..

Thanks

Gary

 

[ps0303]

The next stop is whether or not the board they are connected to is bad. How would you know? Replace the board or call a service tech company out and let them swap out parts to find the issue.

 

[garywi]

Thanks Paul. There is nothing else that is causing it to overheat?

 

[ps0303]

How old is the unit?

Bad bypass spring, obstructed flow of water, or blower motor is not exhausting the heat correctly.

 

[garywi]

Thanks Paul. The heater is 10 years old. I hear the blower motor running.

 

[garywi]

Solved. I closed the external heater bypass valve 50%, directing more water through the heater. Now, no more Hi Lim SW error.

 

[ps0303]

Solved. I closed the external heater bypass valve 50%, directing more water through the heater. Now, no more Hi Lim SW error.

Yes that would cause not enough water flow thru the unit and thus allowing it to over heat.

 

[danpik]

Ideally, you should flow as much water as possible thru the heater. This way it will pull the max BTU's from the heat source and return them to the pool.