Arctic Spa - Intermittent Heat

[Tepid Tub Guy]

I have been struggling with my 2008 Arctic Spa Cub series hot tub.

The heat is intermittent. Sometimes it heats to the desired temperature. Other times is maxes out around 96 degrees. If it is at 101 degrees (as an example), when it dips below 99 degrees, the pump kicks on, but the water doesn't heat. 

I changed the filters. I even removed them. It doesn't help. I installed a new pressure switch and heater. It doesn't help. I replaced the spade connector terminals at the pressure switch. It didn't help.

I'm getting 220 VAC at the heater. The heater measures 10 Ohms when disconnected. I can't verify the current because my meter is limited to 10A.

The pressure switch does open/close when there's flow/no-flow. I am getting no error codes on the display.

The display reads the temperature accurately. The pump seems to be working fine...there is no substandard water flow.

If I flip the breaker, wait an hour, and re-start, things work ok for a little while, but eventually the temp drops down to around 95 degrees, and the pump runs constantly. 

I ordered a new heater relay and will install it when it arrives tomorrow.

Is there anything I am missing, or something else I can try? If the HL switch was bad, I should get an error code, right?

Any guidance is appreciated!

 

[CanadianSpaTech]

3 hours ago, Tepid Tub Guy said:

I'm getting 220 VAC at the heater.

Then the spa is heating... unless there is an issue with the element like it is covered over with calcium and not performing as it should but you said you replaced the heater. If the temp probe sits in a tube with the tip of the tube touching the water in the beater area through the side wall of the spa make sure the temp probe is pushed all the way into the holding tube and up to the tip so it is getting an accurate reading. 

[Tepid Tub Guy]

On 2/22/2023 at 4:36 PM, CanadianSpaTech said:

Then the spa is heating... unless there is an issue with the element like it is covered over with calcium and not performing as it should but you said you replaced the heater. If the temp probe sits in a tube with the tip of the tube touching the water in the beater area through the side wall of the spa make sure the temp probe is pushed all the way into the holding tube and up to the tip so it is getting an accurate reading. 

Thanks for taking the time to reply. I appreciate it. Heater is almost brand new. Unless I got ripped off, the element should be clean. The spa temp reading is always accurate. When the heater works, it's definitely 101 or 102. And when it doesn't kick in, the display accurately follows the drop in temp. When it gets 2 degrees below the set point, the pump kicks in as expected, but the heat level vacillates between mediocre, and simply recirculating the water.

If I shut it off for an hour, it is 50/50 when I flip the breaker back if it begins functioning properly for a while. But it always settles back around 96 degrees if I have it set at 101 (if the lid is on...if the lid is off, it drops lower). I assume the heat from the pump running keeps it around 96F?

My heater relay shipment was delayed until Monday. I'll take a look at the temp probe this weekend. 

[Tepid Tub Guy]

Heater relay replacement didn't help.😡

Spa will heat to the preset temperature (say, 102), but once it drops 2 degrees below the set temperature (100 degrees) the pump kicks in...but the heater is mediocre at-best...if I'm lucky, it maintains the "2 degrees below preset" temp. Other times, the temp continues to drop down -3 degrees...-4 degrees...

And the heater is new, as is the flow switch.

Very frustrating.

[Jay G]

WAY out of left field, but this tub wasn't converted from 110v was it?

[Tepid Tub Guy]

8 hours ago, Jay G said:

WAY out of left field, but this tub wasn't converted from 110v was it?

No. But I'm getting desperate, and appreciate any long shot troubleshooting attempts. Thanks.