Spa temperature doesn't reach set temperature

bmccarty

Bronze Supporter
Mar 8, 2017
41
Sonoma, CA
#1
I am a new pool owner having purchased a house with a pool already installed. I've tried using the spa 6 times and about half of those times the spa temperature never reached the set point while the other times it worked fine.

I have a Pentair system, Master Temp 400, Intelliflo Variable Speed Ultra Energy Efficient Pump, Intelli-Touch System i7+3, Clean and Clear Plus Cartridge filter.

Today I tried again setting the target temperature to 101 and the spa never went above 83 degrees when I look at the readout on the in-home display panel. That panel shows the set point at 101 and the actual at 83. I went to look at the heater display and it said the current temperature was 99 and the set point was 100. So I'm guessing that the heater thinks it has reached it's set point and therefore has stopped heating. Both the Service System nor Service Heater lights are off.

I looked at the filter pressure and the needle has reached the point where it says to clean the filter. Could that be the problem? Are there other things to try on my own to investigate? I did already call my pool pro and of course at that time it heated fine so he couldn't do anything.

Thanks for your help!
Brad
 

ps0303

TFP Expert
In The Industry
Jul 6, 2011
3,959
FL
#4
Yes I would first clean the filter, verify that the valves are rotating correctly when you put the system into spa mode, then turn the heater on and actually sit by it to see how it acts.
 
OP
OP
B

bmccarty

Bronze Supporter
Mar 8, 2017
41
Sonoma, CA
#5
After some time, I've gotten the filter cleaned and the PSI went down about 5 PSI. I've watched the heater when in spa mode and the valves all seem to be doing the right thing, switching from from pool suction and return to spa suction and return. Still the heater kicks off before reaching the desired set point. It still appears that the heater's display is in line with the set point, e.g. current temp is say 99 and set point is 100. But the Intellitouch temp display is reads 92 (or more typically around 88). I measured the water and it's temperature is in line with what the Intellitouch display is reading.

Are there other potential causes for the heater to seemingly reach the set point before the water does? Any possible pump speed settings etc?

Thanks again for any help while I continue my wait (and wait) for my pool pro to visit.

Brad
 

ps0303

TFP Expert
In The Industry
Jul 6, 2011
3,959
FL
#6
The temp sensor for your automation system may need to be calibrated. Do you have the Easytouch automation system?
 
OP
OP
B

bmccarty

Bronze Supporter
Mar 8, 2017
41
Sonoma, CA
#8
The temp sensor for your automation system may need to be calibrated. Do you have the Easytouch automation system?
Can you tell me how the temperature sensor works in conjunction with the temperature display on the heater itself? The temperature I see on the Intellitouch display matches the temperature that I get when I manually measure the water with a thermometer but that is different from the temp on top of the heater display, which one is the automation using? I.e. is the heater obeying the temp on it's display or the temp provided by the temperature sensor?

Thanks again,
Brad
 

ps0303

TFP Expert
In The Industry
Jul 6, 2011
3,959
FL
#9
When you have automation, the automation controls the temp. The heater should be set to the highest temp, usually 104. Then the automation tells the unit when to turn on or off.

So if the heater is set up correctly, if you press the pool or the spa button on the heater, then press the up arrow to make sure the heater is set for 104. That is the highest temp the heater can go to. Once you have done this, do not change anything on the heater. Leave it set on either pool or spa and the temp on it set to 104. Then on your automation system, you would turn the heater on and set your temperature. The automation system will tell the heater to fire up and the automation system will tell the heater when the temperature has been satisfied and then to turn off.

So make sure the heater is set to pool or spa, the temp on the heater is set to 104, then set your automation for spa, and set the temp for the spa, now see what happens. Remember, do not change anything on the heater once you select pool or spa and set the temp on the heater.

There is still a chance the heater might be acting up or the water temp sensor for the Intellitouch.

Here is the manual for the system. Page 84 section 4 talks about calibration of you need it.
http://www.pentairpool.com/pdfs/IntelliTouchOM.pdf
 
OP
OP
B

bmccarty

Bronze Supporter
Mar 8, 2017
41
Sonoma, CA
#10
Thanks very much Paul. I tried all this and it did seem to help, I got the spa temperature up about 98 but it still didn't reach my set temperature of 101. Here's what I tried.

I first did as you said and pressed the spa button on the heater then the red up arrow and increased the temp setting on the heater up to 104. Then I turned on the automation with a set point for the spa at 101. Everything heated well until the water reached about 98 degrees as measured by a thermometer; this temperature also agreed with the Intellitouch water temperature display. But the spa didn't get any warmer. I looked at the heater temperature display (not pressing any buttons) and it was reading 104. This implies to me that the heater had stopped heating because it reached it's set max of 104 and not because the automation told it to stop heating. I'm not clear how the heater's temperature display is different from the temperature sensor's reading (?).

Just for grins, I tried using the Intellitouch temperature sensor calibrate function to adjust the temperature down, thinking that if the automation were controlling the heater, then lowering the calibration would cause it to heat. But this didn't do anything to get the temperature higher, as measured with a thermometer.

So I *think* what's happening is that the heater is turning off before the automation is telling it to, because the heater has reached it max temperature.

So I'm still puzzled.

I've read some posts that mention that if the water flow through the heater is not sufficient, that the heater can hit the max before the water in the spa does. Could I have some issue with water flow causing this?

Thanks again for the great information,
Brad
 

ps0303

TFP Expert
In The Industry
Jul 6, 2011
3,959
FL
#11
I would suspect if it were a water flow issue, the heater would have a knocking sound when running and it would super heater the water inside thus many times providing you a reading of like 120+. So the heater is getting to what it thinks is the max temp. You could try and replace the thermistor on the heater and see if that gives you a better reading.

This is one of those where unless you get an error code on the display, you have to play around with a few parts to see what happens. It's easy for me as I carry the parts and can swap them out to test.
 
OP
OP
B

bmccarty

Bronze Supporter
Mar 8, 2017
41
Sonoma, CA
#12
Thanks again for all your help. The heater is not making any unusual noises and I've never seen the temp reading go above 104. I think I'll have to try and wait for a pro to help me out, I'm not sure I'm willing to try swapping parts at my expense. :)

I posted my issue on a different site and someone also suggested that it could be the thermal regulator, do you have any opinion as to whether that's possibly in the mix also?

Thanks
Brad
 

ps0303

TFP Expert
In The Industry
Jul 6, 2011
3,959
FL
#15
It *not* making any unusual noises. Just what I would think are the normal heater sounds. E.g. The burner sound.


Sent from my iPhone using Tapatalk
Time for glasses for me. I missed the "not" when I read it.

On a thermal regulator, I would expect the unit to make some knocking or banging sounds and shut down as it over heated because the part didn't open up. It's just like a car radiator thermostat.
 
OP
OP
B

bmccarty

Bronze Supporter
Mar 8, 2017
41
Sonoma, CA
#17
Well after 10 days, a filter cleaning and a replacement for the thermistor, the heater temperature is still way above the automation temperature reading and the actual water temp when measured with a thermometer.

My pro is telling me that I need to replace the Pentair Control Board ($$$). First, is this reasonable, does it sound like the most likely cause at this point?

If so, how hard is it for a non-pro like me to replace the board myself and save a lot of money? I'm familiar with circuit boards and can unplug and and plug in new connectors if that's all it takes or is it more complicated than that? Do you need to configure the board or anything like that?

Thanks
Brad
 
OP
OP
B

bmccarty

Bronze Supporter
Mar 8, 2017
41
Sonoma, CA
#18
Just to close this out. It turned out to be a bad control board. There was a lot of evidence of a fairly good mouse infestation with a nest directly under the exposed back of the control board. There wasn't any evidence of chewed wires or other parts so were not clear on the specific cause of the board going bad, but replacing it fixed the problem.

After seeing what it takes to change the board I would definitely do it myself if I ever need to again. The work amounted to opening the access panels, unplugging the old board, unscrewing the board from the heater top, screwing in the new board and plugging the wire connectors back on. It would have saved several hundreds of dollars if I had done it myself.

I've put some 1/4" mesh over the openings as best I can to prevent a re-infestation.

FWIW, the service tech had also tried replacing the thermal regulator first but that didn't fix it.

Thanks for all the input, I'm learning a lot from the TFP site!
Brad