Hot tub will not heat past 84 degrees F

[ScottGreaves]

A couples of days ago I went out to check the chemicals in my Coast Mountain Garibaldi hot tub and found that the temperature had dropped form 102 degrees down to 84.  I tried heating up up but to no avail.  When I ran the pumps, the temperature rose, but when I turned them off, the temperature returned to 84.  I also shot off the breaker for 15 minutes but when I turned it back on, the tub would not heat past 84. I called a local hot tube store and they told me it sounded like I had accidentally put the tub in econo mode and would have to figure out the button sequence to put it back into standard.  Unfortunately, I have not even seen the owners manual for a few years and I believe Coast Mountain is now out of business.  Any suggestions?  Does the hot tub stores theory sound correct?  I have never accidentally put the tub in econo mode in the 8 y ears I have owned it. 

[Dr. Spa™ Ret.]

www.coastmountainspas.com

[ScottGreaves]

Thanks but they went out of business several years ago.

Scott.

[d00nut]

Is there any indication on your control panel of a different mode setting?  Sometimes I run into that when people accidentally put their Hot Spring in Summer Timer.  How much did the temperature rise when you ran the pump?  How long was it running?

There theory could be right, but there are plenty of other things that could cause it not to get to temperature.  However, if it is not getting lower than 84 degrees... I wouldn't make your heater the culprit.

[ScottGreaves]

On the advice of an engineer at work, I shut off the tub at the breaker for 24 hours, then started it up and have now let it run for 24 hours without touching the keypad. 

This time the tub has heated up to 77 degrees and is holding constant.  The digital display does not show any code which would indicate to me that the mode has been changed.  Basically it just shows the temperature with a small flashing dot which I believe indicates that it has not yet met the target temperature (the tub is set somewhere between 100 and 104 degrees).  To be honest, I did not really buy the explanation that I must have hit some incorrect keypad buttons.  During normal use, it is pretty straightforward...arrow up and down for temperaturs and the pump button to turn on the jets. 

[wmccall]

On the advice of an engineer at work, I shut off the tub at the breaker for 24 hours, then started it up and have now let it run for 24 hours without touching the keypad.  

This time the tub has heated up to 77 degrees and is holding constant.  The digital display does not show any code which would indicate to me that the mode has been changed.  Basically it just shows the temperature with a small flashing dot which I believe indicates that it has not yet met the target temperature (the tub is set somewhere between 100 and 104 degrees).  To be honest, I did not really buy the explanation that I must have hit some incorrect keypad buttons.  During normal use, it is pretty straightforward...arrow up and down for temperaturs and the pump button to turn on the jets.  

The figure 84 degrees probably led to that suggestion. My tub, set to 104, has an economy button that all it does it drop the tub 20 degree, hence 84.  Some tubs do the same thing via a sequence of pressing other buttons.  My tub can be switched between degrees F and C by pressing some odd combination and it seems whenever we have new people in our tub, they put their hands all over the control panel and switch it that commie loving Celciuis system.    
But it was only heating to 84, then 77 on another occasion, did your outside air temp change a lot?  Perhaps the heating element isn't working properly and is struggling to maintain any temp above ambient? I don't think you said where you lived.

Dr Spa gave you the website, which even if the company is out of business still seems to be up.  Did you look at it to see if any contact information may still be valid?

[ChaiSTi]

Have you checked for voltage across the heating element?  0 Vac would indicate that either your circuit board heater relays are fried or that there are conditions that would disable voltage to the heater i.e. flow issue or hi-limit issue.