Brand new temperature sensor way off

Mr3dPHD

Member
Dec 1, 2024
6
Melbourne, FL
Pool Size
17000
Surface
Plaster
Chlorine
Salt Water Generator
Hey everyone, I read through a bunch of posts here about air temperature sensor being off. Most of the threads say the reading is too high and they're worried their freeze protection won't kick on, and the advice seems to be sensor location.

I have the exact opposite issue. My sensor is perpetually under 30° even though it's 70°+ outside, so my pumps are constantly running and there's no way to turn them off as far as I can tell because of freeze protection. This system is only about 6 months old so it's a new sensor. Should I just buy a new one?
 
It should be under warranty...

That said, they are very cheap and it would most likely be less effort to just buy and install a new one.

It could also be that your automation system is bad and not reading the air temp sensor correctly.

Thanks,

Jim R.
 
Welcome to the forum.
If you tell use what equipment you have we likely can guide you turn off the freeze protection. I doubt your area needs that to be available.
 
Welcome to the forum.
If you tell use what equipment you have we likely can guide you turn off the freeze protection. I doubt your area needs that to be available.
We don't typically but around once a year it may dip into the high 20s. What temperature do I need to worry about with a salt water system? I imagine it's lower than 32°.
 
PHD,

Welcome to TFP! How old is your unit? Very likely it's just a bad thermister. Has it always done this? They usually do fail high but the opposite can happen as well. It would be very helpful if you could add your signature. This gets you answers quicker and helps our volunteer experts to be more efficient with their time. It's easy to do here's how.

Chris
 
If you have a multimeter, you can test the temperature sensor.

Read Temperature Sensors - Further Reading

Reading in the 30's when the temperature is in the 70's shows high resistance. Check that the sensor wires are cleanly under the screws on the connector.

1200px-10K_thermistor_chart.png
 
  • Like
Reactions: setsailsoon
Sorry for the late response everyone! I finally got my signature updated. I'm going to try testing the sensor with my multimeter tomorrow. If it doesn't look right, I'm just going to order a new sensor and try installing it myself. Am I right that the exact same sensor is used for both water and air? I was looking at this one. The pool and all the equipment is very new. We were first able to swim in March of this year ('24).

@mknauss, I think I may want to disable the freeze protection until then as well. I'm not sure how to do that though. iAqualink is not very intuitive lol.


PoolTopDown.jpg
 
Am I right that the exact same sensor is used for both water and air?

Correct.

I was looking at this one. The pool and all the equipment is very new. We were first able to swim in March of this year ('24).

if your sensor is bad put in a warranty claim with your builder and get a new Jandy sensor.

This one for $20 will work fine and you will have a spare. Check that the 20’ cord is long enough.

 

Enjoying this content?

Support TFP with a donation.

Give Support
How are you trying to do that?

Why?
I'm using the instructions @mknauss posted above inside the iAqualink web app. Any of the items listed in the settings can have the "X" toggled on or off except for the one for the filter pump. As for the temperature, when I type anything lower than 34° it returns an error that 34 is the lowest you can set it to.
 
Freeze protection for the filter pump is on by default.

Jandy is Big Brother.

Call Jandy Support and discuss with them why you want to be able to disable it.
 
M,

Not sure if Jandy allows you to 'calibrate' your air temperature sensor or not..

Pentair does, so I adjust it so that my air temp reading is always 2 or 3 degrees high. This means when the system thinks it is 34 degrees it is actually 32 degrees.

Thanks,

Jim R.
 
You can use a 10k resistor in place of the thermistor to make it read 77 degrees all the time, which will disable Freeze Protection.

If the 10k resistor does not make the system read 77 degrees (+/- 1 degree), then the board is probably defective and needs to be replaced.

You can set the pump to run all the time at low speed.

You can control the Freeze Protect Speed.

You can disconnect the Air Temp Sensor and it might prevent the Freeze Protect from engaging or it might make it turn on all the time.

9.11 Freeze Protection.

NOTE By factory default the filter pump circuit is freeze protected and cannot be removed from the freeze protection.

Use Freeze Protection menu to assign freeze protection to your pool and spa equipment.

When a piece of equipment is assigned to freeze protection, it will turn on when the iAqualink detects freezing conditions.

The main filter pump is freeze-protected as a default.

Activation temperature can be adjusted between 34°F (1°C) and 42°F.

Default freeze protection activation temperature is 38º F (3°C) and will deactivate within two degrees..

NOTE The filter pump is always assigned to freeze protection.

Freeze Protection.

In the freeze protect mode the pump will turn ON and be set to at least the freeze protect speed.

If the filter pump speed is higher than the freeze protect speed, then the pump will run at the filtration speed.

Also, if speeds have been assigned to auxiliaries and if those auxiliaries are freeze protected, the pump will be set to the
highest of the speeds

SENSOR OPEN.

This error message indicates that the sensor is not installed properly or is malfunctioning.

NOTE If the message reads WATER TEMP OPEN, the heater will not fire.

If message AIR TEMP OPEN is displayed, freeze protection will not operate correctly.


https://www.amazon.com/California-JOS-Carbon-Resistor-Tolerance/dp/B0BR67DJHM

https://www.digikey.com/en/products/detail/yageo/MFR-12FRF52-10K/13921893

https://www.digikey.com/en/products/detail/ohmite/MRA0207-10K-B-15PPM-TA/18689054

https://www.digikey.com/en/products/detail/koa-speer-electronics-inc/CF1-2CT52R103J/13538334
 
Last edited:
TFP is a registered 501(c)3 non-profit that is maintained by user donations.

All of our content is free of advertisements.

Please consider donating at:

 
Why is the builder not helping you with this?

Have you filed a warranty claim with Jandy?

If no, why not?
The builder has been awful. They built a great pool but the second we made the final payment, they almost never respond when I contact them. I hadn't set up a claim with Jandy because the sensor is only $20. Figured I'd just try that first.

Needless to say, I *did* try that first and it worked! The sensor was bad. The new one I got from Amazon did the trick. Thanks so much for all your help everyone!
 
  • Like
Reactions: JamesW
Glad we could help.

TFP is a member supported 501(c)3 non-profit that is volunteer staffed and has no ads. Your support keeps the servers running so we can be here to help you. It would be helpful if you considered supporting TFP so we can be here to help in the future....

s
 
  • Like
Reactions: JamesW

Enjoying this content?

Support TFP with a donation.

Give Support
Thread Status
Hello , This thread has been inactive for over 60 days. New postings here are unlikely to be seen or responded to by other members. For better visibility, consider Starting A New Thread.