HL (high limit) error continues.

[Douglas]

I have been trying to chase down an elusive prolem with my spa.  It started with an occasional HL error reading.  I'd shut it off, turn it back on and it would go away.  It started getting more frequent to where I called and talked with a specialist who said it was more than likely a bad motor.  I took the motor in for a rebuild, reinstalled it and the next morning had an HL error.  Now it's back to having to reset the unit once a day to clear the error.  I'm not sure where to look next.  Every once in a while the heating unit will come on but there will be no motor running.  I know it's on because I can hear the water in the heating tube sizzling.  I can watch the digital read out show the temp rising rapidly until it hits the safety shut off level of around 125 degrees.  At this point it shuts down but comes back on after a while, eventually the motro kicks back on and it continues to heat the tub normally but displaying the HL error until I clear it again.

[CanadianSpaTech]

What brand of spa? Post photos of the circuit board and the schematic on the inside cover if there is one so we know what you have. I am leaning temp sensor. 

[Douglas]

Believe it or not the spa is 35 years old.  I've had numerous control units and various pumps and motors over the years but the old round, redwood Sonoma tub is still operational.  Well sort of.  I'm now using an EasyPack control unit from SpaDepot.com and a 2hp motor.  I just had the motor rebuilt thinking it was the problem.  The motor did have some serious issues but I'm still getting the HL message.  I have never had deposits or buildup of any sort in the system and I think I have sucessfully bled any air out.  It runs well when it's running but every once in a while the heat comes on without the pump.  I'll lhear a sizzeling in the heating tube and watch the temp go up until it triggers the auto shut down.  If I leave it alone it eventually starts running again but with the HL error on the readout.  I'll then shut down power, turn it back on and it runs normally again.

[Douglas]

[RDspaguy]

On 11/26/2021 at 5:10 PM, CanadianSpaTech said:

Post photos of the circuit board

Also the topside, box cover, and equipment area. Ixm not aware of a digital spa control system in use 35 years ago.

On 11/26/2021 at 5:10 PM, CanadianSpaTech said:

leaning temp sensor. 

Wouldn't engage the heater without the pump. I'd say stuck heater relay, and HL relay is shutting it off.