2001 Hot Spring Prodigy Not Heating

[lkneisler]

I have a 2001 Hot Spring Prodigy that's not heating. Running on 110v.

The circ pump is perfect and there are bubbles. The filters were pulled out just to be sure it wasn't a water flow problem.

When I reset the GFCI at the plug, the heater light on the board goes ON for a few minutes, then it turns OFF and stays off, very consistently, every time I reset the GFCI.

The green light is always on.

The red light on the control panel is solid.

I replaced the thermister with the same result; the heat light goes on then it goes off after a few minutes and stays off.

When the heater light is on, there is power at the heater relay board and to the heater leads.

I looked at the heater relay board and it does have a tiny dark spot right at one of the solder points for K1. But there is power going to the heater leads and the heat light is off, so that makes me think it's something else.

What else can I do, check, look at?

Thanks for your help! Lori

[Peteyboy]

Check the top LED above the heater LED on the circuit board. Is it lit?

Which Thermister did you replace?

[lkneisler]

Check the top LED above the heater LED on the circuit board. Is it lit?

Which Thermister did you replace?

The LED (green) above the heater LED is on and stays on.

What I replaced was the temp sensor.

[Peteyboy]

I would try the control thermister, it doesn't cost much.

What temp do you have it set for? I'm sure you are turning the temp up plenty.

One thing I would do is convert the control box so the display will show actual temp.

Unplug the spa, open the control box and find a vertical row of little pin jumpers marked JP1 - 12. Find a jumper that is only on one pin and not across the 2 pins. Put this jumper across the 2 pins at JP10, plug the spa back in and it will show actual temp.

[lkneisler]

I would try the control thermister, it doesn't cost much.

What temp do you have it set for? I'm sure you are turning the temp up plenty.

One thing I would do is convert the control box so the display will show actual temp.

Unplug the spa, open the control box and find a vertical row of little pin jumpers marked JP1 - 12. Find a jumper that is only on one pin and not across the 2 pins. Put this jumper across the 2 pins at JP10, plug the spa back in and it will show actual temp.

I believe that's the one I replaced. There are two, right? One is hi-limit the other is the temp (or control) thermister? I should replace the other one anyway.

I had the temp at 101 then 104. And the water is fresh so FREEZING!

Thanks for the info about showing the actual temp. I'll have to try that out. Always so annoying not being able to see the actual temp.

Right now the spa is all apart waiting for a new heater relay board. When that's done I'll continue this most wonderful hair pulling experience.

Someone mentioned the control head might be a problem.

[Dan.The.Spa.Man]

I would try the control thermister, it doesn't cost much.

What temp do you have it set for? I'm sure you are turning the temp up plenty.

One thing I would do is convert the control box so the display will show actual temp.

Unplug the spa, open the control box and find a vertical row of little pin jumpers marked JP1 - 12. Find a jumper that is only on one pin and not across the 2 pins. Put this jumper across the 2 pins at JP10, plug the spa back in and it will show actual temp.

I believe that's the one I replaced. There are two, right? One is hi-limit the other is the temp (or control) thermister? I should replace the other one anyway.

I had the temp at 101 then 104. And the water is fresh so FREEZING!

Thanks for the info about showing the actual temp. I'll have to try that out. Always so annoying not being able to see the actual temp.

Right now the spa is all apart waiting for a new heater relay board. When that's done I'll continue this most wonderful hair pulling experience.

Someone mentioned the control head might be a problem.

Is the summer timer option on? It will show a sundial/timer looking icon on the control panel. If so the circ pump will shut off shortly after resetting the breaker as will the heater. If the summer timer is on it will take quite a while for a 110volt tub to heat up.

[lkneisler]

Is the summer timer option on? It will show a sundial/timer looking icon on the control panel. If so the circ pump will shut off shortly after resetting the breaker as will the heater. If the summer timer is on it will take quite a while for a 110volt tub to heat up.

Thank you, yes we were told to check that and it was not in Summer mode. Plus the circ pump did stay on when the heat light kicked off; it'll stay running til we shut off the power.

Any thoughts on the control head (thing behind the control panel) being a problem since the thermisters check out okay? Or is there anything else to look at before replacing it?

My understanding is that if the circ pump is on and flow is good, and heat on light goes off, and the green light is still on, and the control panel light (red) is solid... then the problem is the temperature sensor. I need to go drink, huh?

[mrfixit]

If you have power to the heater leads, as described in your original post, then I would guess your element is gone.

[Dan.The.Spa.Man]

If you have power to the heater leads, as described in your original post, then I would guess your element is gone.

I was confused by that a little as well.

I think lkneisler meant that there was power going to the leads for the short time that the red "heater on" light was lit but then the light goes off the voltage drops off as well.

Definitely make sure that you replaced both thermistors, there really isn't much more to it. After that, yes, the control head or the IQ box. But that would be pretty rare to have to replace those parts for a heater light not coming on.

[lkneisler]

If you have power to the heater leads, as described in your original post, then I would guess your element is gone.

I was confused by that a little as well.

I think lkneisler meant that there was power going to the leads for the short time that the red "heater on" light was lit but then the light goes off the voltage drops off as well.

Definitely make sure that you replaced both thermistors, there really isn't much more to it. After that, yes, the control head or the IQ box. But that would be pretty rare to have to replace those parts for a heater light not coming on.

Right, sorry to be confusing, power to the heater leads is there when the light is on, but then power is gone when the light goes off.

I'll start with replacing the other thermister and see what happens.

Thank you everyone for your help!

Lori

[lkneisler]

Just to follow up...

I replaced the heater relay board and the spa is working / heating perfectly.

So... if the heater light is off on the main board it very well may be the heater relay board after all.

I still believe the situation was very unusual; not typical. Anyway... I hope all this might help someone somewhere down the road!

[Bob S.]

I have a similar issue on my 2001 120v prodigy. My pump went out, so I replaced, along with a new heater, which came with two new sensors. Refilled and all worked well. the tub heated for around 3 weeks, then stopped heating. jets and recirc pump work fine. Cleaned the filters. The heater will go on for a minute or so, after plugging in the spa, then kick off. No blinking lights or indicators. The heater board looked slightly fried, so I replaced with one of the new re-designed upgraded boards. I still get the heater kicking off after around a minute.  I did have to splice the two sensor connectors onto the new sensor cables. I can only think that it might be the sensor splices, however it did work fine for 3 weeks. What should the ohms be for those two sensors?  Any advice will be appreciated.