Spa Board Doctor

The hot tub temperature sensor should be accurate within a couple of degrees to a known good digital thermometer. Did you make a splice connection to the old temp sensor harness wires or eject the pins from the old harness (no splice)? A spliced connection can add resistance to the circuit which could affect the accuracy of the displayed temperature. You could drape the old temperature sensor over the lip of the tub into the water and reconnect it to the harness temporarily to see if it is accurate to your digital.

White jumper wires for each output receptacle on the board go to either "RED AC" for 240V output or "WHITE AC" for 120V output. There are multiple male spade terminals on the board at "RED/WHITE AC", any open spades can be used.

Can you hear an audible relay click on the board when you press the "Jets 1" button? If yes, it's either a bad relay, fuse, or break in the trace that feeds the relay. If no, then sometimes, when a relay burns down internally, the coil circuit of the relay short circuits. This short can feed back to a transistor array which burns up too. This is a repairable failure, however, the skills and knowledge required for the repair exceed the scope of a forum.

Sounds like the heater relay is stuck on.

These boards, even brand new out of the box, are hit an miss as to whether they will work or not. There is a board repair option that works in most cases however, if it's brand new and under warranty, I'd return and hope you get a good one next time.

With power on and meter set to 240VAC (or higher), test across L1 and L2 on the input terminal, you should read 240V. Next, test from N to L1 (120V) and N to L2 (120V). If these values are present, with the power still on and the same meter setting, test across the three fuses, the meter should read 0V. If you read line voltage i.e. 120V or 240V, the fuse(s) are bad.

Sorry, just realized you're probably talking about the sensor mount here in the pipe? Toothpick or silicone wouldn't work well here because it's a wet well. You could remove and plug this fitting with a 1/4"NPT (I think) plastic plug, then tap a new 1/8"NPT hole and use this fitting and sensor (splice the new sensor wires to the old sensor wires). P/N: 34-0202B-K

Any possibility that one of the jet pumps got plugged in to the circ pump jack? Over amperage on this circuit may have caused a failure?

Okay to be a little skinny, shim against it with a toothpick or add a dab of silicone to hold it in place. As long as it is in the heater thermowell it will do it's job.

On J21, test for 240VAC between pin 2 and the second screw from the top on the input terminal (L1/HOT black wire/area 2). If you have 240V here it would have to be a bad circ pump relay - not uncommon, but strange for a brand new pack.

Best to test for voltage at the circ pump receptacle on the board. Unplug the heater. Wait for the prime mode, then press a temperature key, from top to bottom on the circ pump receptacle, test between pins 2 and 4, there should be 240V.

Maybe try a memory reset. Turn power off, switch S1 switch 6 to on, turn power back on and wait for prime mode, turn power off and switch S1 to off, turn power back on and see what happens. If this doesn't work there would almost have to be a break in the circuit board trace or relay that feeds the circ pump receptacle. It also doesn't make sense that the circ pump works in the pump 1 receptacle, unless you are pressing the jets 1 button to activate the pump.

You have it set to setup 2? The circulation pump wires should be inserted into the AMP plug as follows: green, white, space (no wire), black. Is this correct?

It's 1-1/2" i.d. - thanks. When you boot the system and the display says prime mode, press a temperature key (either up or down), and the circulation pump should come on. You might try removing the filter(s) first and try booting without the filters installed. It sounds like a water flow issue i.e. dirty filter, too many heater return jets or waterfalls (if installed) shut off. With this circulation pump and heater design, proper water flow is critical. You'll want to keep your filters clean and rotated and make sure that all the returns (where the heated water comes out) are open and clear of debris.

Are the plumbing connections for the circulation pump 1-1/2"?