I checked the low-flo pump and it always seems to be running (not sure of the speed). The filters are new and so that shouldn't be the problem. I can hear the heater relay turn on and off when I bring the thermostst dial past setting 3.

The circuit breaker appears to be fine yet I'm not sure what could go wrong with it. Perhaps you can explain.

I checked the heater resistance and it is about 10 ohms at the lowest (it tends to read about 15 to 20 ohms). When I turn up the thermost past 3 and hear the relay kick in I check my home's electric meter and it spins quickly. When the relay is off the meter spins very slow. I know this is a cheap way of reading ampergae but I trust it gives a good indication.

That leaves the flow switch or the thermister. Is there a way to validate the flow switch? What about the thermister?

Don't test when the meter spins very quickly, it's working fine at that point. Wait until you turn it up, and the meter doesn't spin.

I don't understand what I'm supposed to further test when the meter is spinning slowly. All of my tests mentioned don't matter whether the meter spins slow or fast: filters are new, relay engages, and low-flo pump is ALWAYS running (not sure at what speed, since it sounds the same all the time).

Is there a way to test the flow sensor or thermistor?

Sorry, I was reffering to troubleshooting while the meter is whipping around. You mentioned, "When I turn up the thermost past 3 and hear the relay kick in I check my home's electric meter and it spins quickly. " I was just letting you know that your poor man's amp meter works. And if the heater's pulling amps, it's good.

You're going to have a hard time troubleshooting until you turn it up and the meter doesn't spin. The flow switch doesn't get voltage until high speed is energized, and there won't be enough flow to close the switch until high speed is energized (by turning up the heat)

You can guess, and start throwing parts at it, but if it heats initially, it's a safe bet the flow switch and thermistor are both good.

Update....

I previously said that in order to get my tub heating again I have to reset the circuit breakers. What I found out this week is that even by doing that the heater doesn't always kick back on. Only a small percentage of the time will it heat.

What happens every time is that the relay switches on and off as I increase and decrese the thermistat (about setting 3 of a 9 scale). The low flow pump always runs (not sure the speed).

Based on this my guess is that the flow switch might be bad. Then again, if the flow switch is bad will I hear the heater relay click on and off?

My only other thought is that the circuit breaker could be bad. I'm not sure how to determine this. I know the GFCI reset works when tested.

Perhaps I have a make/break connection in the wiring someplace.

Any thoughts?

If the flow switch is bad, you will not hear the heater relay or flow switch relay open or close. (there are both)

When you turn it up, there are actually two clicks at the same time. One click is the flow switch relay, the other is the heater relay. By unplugging one or the other (one at a time), you should hear a click when either one is unplugged (when the heater is operational)




You might need to drop the control box to test if the heater relay is working properly.