2000 Hot Spring Prodigy Not Getting Hot Enough

[Ryan0751]

Last summer my 2000 Hot Spring Prodigy's heater failed (the tub went cold). I had the local spa company come out and they determined the heater to be faulty, and replaced it with a newer unit (that looks smaller, but the repairman insisted it was a newer better unit).

Then early this summer, the tub started to get WAY too hot (uncontrolled, around 110 before I shut it off). The spa company came back, and replaced the regular and high limit thermistor.

Now I'm noticing that the tub, even though it's set at 104 degrees, will not heat to above 100 degrees (more like 99 or so). I verified this with two different thermometers, and it definitely does not "feel" 104 degrees.

Does anyone know if this is something I can adjust or fix on my own? Tonight I've enabled the 'override' settings and have pushed it up a few degrees, I want to see if that helps in the morning. But it would be nice if the digital readout were correct.

[hottub.pool_boy]

if you have it set for 104 and it isn't within a degree + or -, then there's a few things to look at. If you haven't CHEMICALLY cleaned your filters in the last 3-5 weeks, it's time. Secondly, do you see an icon on the control screen of a sun/timeclock? That would mean your summer timer is on...and would affect your spa ability to heat. All things considered, it sounds as though the temp sensor is out of spec. All WATKINS parts come with a year warranty. Replace the temp sensor.

[Ryan0751]

Hmm, I did check and the summer cycle mode is definitely not set.

The filters are actually less than a year old.

Is the temp sensor easy enough to replace on my own?

if you have it set for 104 and it isn't within a degree + or -, then there's a few things to look at. If you haven't CHEMICALLY cleaned your filters in the last 3-5 weeks, it's time. Secondly, do you see an icon on the control screen of a sun/timeclock? That would mean your summer timer is on...and would affect your spa ability to heat. All things considered, it sounds as though the temp sensor is out of spec. All WATKINS parts come with a year warranty. Replace the temp sensor.

[spatech (the unreal one)]

The filters are actually less than a year old.

.. but when is the last time they were thoroughly cleaned. Take the circ pump filter out overnight and see what that does.

[Ryan0751]

I just cleaned them this weekend (drained/refilled the tub). I didn't chemically nuke them or anything, but they still look brand new and the tub gets light usage by just myself.

The thermistors are inserted near the heater, correct? The green "ready" light on the control panel is lit, even when the water temperature isn't hot enough according to my thermometer. That leads me to think the thermistors aren't measuring the temp correctly. I would think that if the filters were clogged, the spa wouldn't be able to get warm enough, and the green ready light wouldn't be on? Although, if the water isn't circulating properly, then the water near the heater would be warmer than the reset of the tub. Perhaps I should just yank the left filter (the always "on" one) for a while and see what happens?

Last night I cranked the temp on the control panel up over 104 using the "override" settings, and this morning it did bump up a few degrees.

Are the probes easy to remove? If I pull them out, is water going to go everywhere? What would the process be? Power the spa down, clamp the hoses leading to the heater, replace the thermistors, and power it back up?

The filters are actually less than a year old.

.. but when is the last time they were thoroughly cleaned. Take the circ pump filter out overnight and see what that does.

[Flyonthewall]

try the filter trick for sure. some hss from approx. your year have needed heater board replacements. it is a square circuit board mounted inside the iq conrol (black box). the heater board does not make up all the circuitry in the iq box. you may notice some burning on it if it is bad. it probably isn't bad if you're heating as much as you report.if your filters are original they might just be shot. they are past their lifespan.

[Dan.The.Spa.Man]

try the filter trick for sure. some hss from approx. your year have needed heater board replacements. it is a square circuit board mounted inside the iq conrol (black box). the heater board does not make up all the circuitry in the iq box. you may notice some burning on it if it is bad. it probably isn't bad if you're heating as much as you report.if your filters are original they might just be shot. they are past their lifespan.

Those heater boards started in the 2001 HotSprings.

The sensors are only sensitive to within 2 degrees, so if you want it hotter then just turn it up. You should be able to get the tub to 108 with the upper temperature settings on that year.

If you want to change them, the method is just as you said.