I have a caldera spa and the heater is not working. I replaced the heater and it still is not working. Could it be a sensor?

What year is it and any error codes like 4 flashing lines...is the 'temp' light flashing, or flo readings?

Its an 2001 I believe and no errors or anything are showing. I pulled the panel cover and the heater light is on but the heater is not working. Its circulating the water fine.

Is the panel where the heater light is a metal silver box or a blue or black plastic one?

Its a blue plastic box. You have to pull the cover on the box to see the light. The heater looks like a trombone if that helps and there is a sensor that straps to the stainless tube on the heater.

I would check in the upper left corner of the box for burn marks around the relay to the heater. If there are no burn marks I would still check to see if you have 220 volts there.

I checked it and there is four dashes flashing in the display. What does this mean?

You didn't have the four flashing lines before but you have them now?

Sounds like you could have several different problems, because before you said that the heater light was on but it wasn't heating...this can't happen with the flashing lines.

Perhaps a bad hi-limit, low flow from the circ pump, summer timer on, or even too much foam in the water.

I would pull the filter out and reset the breakers and watch the tub for a while.

After a few minutes:

1.check to make sure the 'temp' light is not flashing...if so...bad pressure switch

2.Make sure that the circ pump is pushing out water

3.If you have an ozonator you can take the 1/8" line off of the injector valve while the tub is on...if water pours out of it then you don't have enough flow from the circ pump.


Are you in a colder climate and do you have the summer timer function engaged? If so...if the heater was on when the circ pump shuts off then the residual heat causes the heater to get too hot... thus producing the four flashing lines.

I've also seen too much foam on the water surface cause the circ pump to cavitate while the jet pumps are on...also causing the flashing lines.

Also, when the jet pump turns on by itself once/day...if there is not enough water in the tub the circ pump will not get enough water and cause the flashing lines.

Check all these things first..if not any of these it may be the hi-limit sensor.