Pentair Mastertemp 400 Max Temperature Setting

Hello. I have a pentair mastertemp 400 heater and we recently had some electrical work done and the pool equipment breakers were all shut off. This caused the heater to reset to the default settings and now we can't get the spa over 100 degrees. I read a lot of the advice on the forum and know I need to reset the temp by pressing the yellow button on the control board under the cover. I followed the instructions in the manual but the display doesn't turn on when I press the yellow button and I have no way of raising the max temperature.

There is an iaqualink controller installed as well and I understand there may be something I need to do with the firemans switch wiring to engage the yellow button to reset the temp but I don't know exactly what that is. Does anyone have any advice on this and what I need to do to get that yellow button to work?

Thanks in advance!
 
Welcome to the forum!
Is the heater direct wired to power or through a relay? It needs power to it for the process to raise the max temp to work.
I suggest you read ABC's of Pool Water Chemistry.
I don’t know if it is direct wired or through a relay. It turns on and off through the iAquaLink system so if that’s what you mean then it would be a relay. Is there something specific I can look for to determine?
 

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
34,767
Laughlin, NV
I suspect it is through a relay. You would need to activate that relay (should be your normal Pool Mode) and then see if the heater responds.

If not, you might have to jumper the Firemans Switch. I would like to ask @JamesW for his input prior to you going that far.
 

JamesW

TFP Expert
Mar 2, 2011
22,072
Set the desired temperature in Aqualink to be higher than the pool water temperature and that should turn the heater on.

What is the current water temperature displayed in Aqualink?

What is the desired temperature set in Aqualink?

I don't think that you will need to do anything with the yellow button.

Press the Pool On or Spa On button if the display does not come on.

See what the temperature is on the display and then press the up arrow to set the temperature to a few degrees higher than you will want to heat the water.
 

ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
22,248
Northern NJ
Pool Size
35000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-60
See page 37 in https://www.pentair.com/content/dam.../heaters/Manual-MasterTemp-472592-English.pdf


Maximum Temperature Set Point
The heater comes factory set with a maximum temperature set point at 78° F (25.6 c). for the pool mode and 100° F (37.8 C). The Installation Manual describes how to increase the maximum temperature set point of the pool and spa. It involves unbolting and removing the door panels, accessing the control panel board on the underside of the top cover, and locating the yellow button on the corner of the control board.

Pentair MasterTemp Maximum Set Point.PNG
 

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
34,767
Laughlin, NV
Allen - his first post stated he tried that process but the heater did not power on. The heater needs power to follow that process.
 

ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
22,248
Northern NJ
Pool Size
35000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-60
Allen - his first post stated he tried that process but the heater did not power on. The heater needs power to follow that process.

I missed that. I would try some contact cleaner around the yellow button. If the yellow button does not trigger the reset logic then he has a board problem.

I would pull the board and look carefully for any flaws around the yellow button.
 
Set the desired temperature in Aqualink to be higher than the pool water temperature and that should turn the heater on.

What is the current water temperature displayed in Aqualink?

What is the desired temperature set in Aqualink?

I don't think that you will need to do anything with the yellow button.

Press the Pool On or Spa On button if the display does not come on.

See what the temperature is on the display and then press the up arrow to set the temperature to a few degrees higher than you will want to heat the water.
Set the desired temperature in Aqualink to be higher than the pool water temperature and that should turn the heater on.

What is the current water temperature displayed in Aqualink?

What is the desired temperature set in Aqualink?

I don't think that you will need to do anything with the yellow button.

Press the Pool On or Spa On button if the display does not come on.

See what the temperature is on the display and then press the up arrow to set the temperature to a few degrees higher than you will want to heat the water.
No matter what temperature we set the aqualink to or on the heater display controls, the spa never goes over 100 degrees. It will turn on and off and maintain temp but will never go over the default 100 degrees. My question is how to bypass the automation wiring so that something happens when I press the yellow reset button to raise the max temperature
 

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JamesW

TFP Expert
Mar 2, 2011
22,072
What is the current water temperature displayed in Aqualink?

What is the desired temperature set in Aqualink?
 
What is the current water temperature displayed in Aqualink?

What is the desired temperature set in Aqualink?
The desired temperature is 102 and I have tried that, 103, and 104.

The current water temp never goes above 100. The heater shuts off at 100 and then turns back on when it drops down to 99 and then back off again at 100
 

JamesW

TFP Expert
Mar 2, 2011
22,072
Is the Pool On or the Spa On light lit on the heater?

What happens when you press the up arrow?

If the Pool On light is lit, press the Spa On button and then press the up button to increase the temperature setting to 104.

Is the water temperature reading correct from the heater and the Aqualink?
 
Is the Pool On or the Spa On light lit on the heater?

What happens when you press the up arrow?

If the Pool On light is lit, press the Spa On button and then press the up button to increase the temperature setting to 104.

Is the water temperature reading correct from the heater and the Aqualink?
Yes the Spa light is on and the heater works as expected. The only thing it does is max out at 100 degrees instead of whatever I set the temperature to. Even if I set it to 102 on the control panel on the heater or the aqua link. It is just defaulting to the factory settings of 100 degrees for the spa. I know I need to adjust the max temp setting by following the steps in the manual. I am just getting stuck at the reset button step.

All I need to know is how to bypass the automation wiring and get the unit to respond to my reset button.
 

JamesW

TFP Expert
Mar 2, 2011
22,072
You can jump the fireman's switch terminals together.

Make sure that you understand exactly what you're doing before you do it.

Do at your own risk.

Pentair_MasterTemp_Firemans_Switch.jpg
 

JamesW

TFP Expert
Mar 2, 2011
22,072
The fireman's switch should go to the automation where a switch closes when the automation wants the heater to turn on.

So, you just jump the two terminals together to do the same thing.
 

JamesW

TFP Expert
Mar 2, 2011
22,072
Can't you do the procedure when the heater comes on?

Is the heater display temperature accurate?

Is does the heater up button show the set temperature?
 

JamesW

TFP Expert
Mar 2, 2011
22,072
Even if I set it to 102 on the control panel on the heater or the aqua link.
Can you set it to 102 on the heater control panel?

If it's set to above 100 in Aqualink, then the fireman's switch should be closed all the time.

We are missing some important information that we need to understand exactly what's happening.

The heater should be powered all the time and not through a relay.

Maybe have the electricians back out to check everything if you can't get it figured out.
 

JamesW

TFP Expert
Mar 2, 2011
22,072
You can try putting the AquaLink in Service mode and then pressing the heater button to activate the heater.

What is powering the heater, is the power supply going through a relay?
 
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