Adding a second water temp sensor

[poolman112]

Hi everyone, I have a Jandy iaqualink system running my pool with attached spillover hot tub.

The water temp sensor is mounted on the pvc right before the pump inlet.

The temp sensor (connected to the pool temp sensor on the panel) has been reading 104 with the heater on but in actuality, the water temp is 100. As a result, it is turning off the heater too early. I can't calibrate the sensor any lower in the iaqualink interface. I suspect the temp sensors is faulty.

So- is the recommended fix here to replace the water temp sensor in the current location--

Or would it be better to add a secondary water temp sensor on the spa water temp sensor circuit on the panel?

Basically- is there any need to have two water temp sensors for pool or spa? When the system is in spa mode it recirculates the spa only .

 

[ajw22]

Replace your water temperature sensor.

Post pics showing where your water temp sensor is located. There may be a better location for it in your plumbing.

How are you measuring that your water is 100 when the Aqualink says 104?

The Aqualink does not support two water temperature sensors.

 

[poolman112]

Replace your water temperature sensor.

Post pics showing where your water temp sensor is located. There may be a better location for it in your plumbing.

How are you measuring that your water is 100 when the Aqualink says 104?

The Aqualink does not support two water temperature sensors.

Thanks for your reply. Photos attached.

I am measuring it using a thermopen thermometer in the spa. The ultratemp heat pump internal measurement is also 100. Jandy is reading 104 and therefore turning off the heat pump when it hits 100.

I have also already set the -4 calibration so its reading about 8 degrees off of the nominal water temp reading.

I ordered a replacement sensor and will install it today.

 

[ajw22]

I would remove the -4 adjustment at the Aqualink and see what actual readings you get.

If you have a multimeter you can test the resistance of the temperature sensor based on this chart…

Temperature Sensors - Further Reading

www.troublefreepool.com

 

[poolman112]

Thanks. Ill test that today and report back. What do you think of the plumbing setup and location of the sensor in my current arrangement?

 

[ajw22]

What do you think of the plumbing setup and location of the sensor in my current arrangement?

Typically the water temperature sensor is installed between the filter pump and filter or right after the filter output before the heater.

But your plumber did not think about leaving a piece of pipe to install the sensor in those locations so someone improvised and put it before the pump suction. And it looks like even there they barely squeezed it into the space on the pipe.

Do you use that tablet chlorinator?

It looks like your spa spillover is always running in POOL mode. You should consider enabling SPILLOVER with dip switch#3 and only running the spillover twice a day for 15-20 minutes. See Jandy Aqualink RS - Further Reading

 

[poolman112]

Typically the water temperature sensor is installed between the filter pump and filter or right after the filter output before the heater.

But your plumber did not think about leaving a piece of pipe to install the sensor in those locations so someone improvised and put it before the pump suction. And it looks like even there they barely squeezed it into the space on the pipe.

Do you use that tablet chlorinator?

It looks like your spa spillover is always running in POOL mode. You should consider enabling SPILLOVER with dip switch#3 and only running the spillover twice a day for 15-20 minutes. See Jandy Aqualink RS - Further Reading

View attachment 535150

Hi,

I replaced the water temp sensor today and the new one is reading 4 degrees less than the old one. So- with the temp calibration at -4 it is reading spot on now and consistent with digital thermometers and also the heater thermometer.

I don't use the tablet chlorinator. I did when I first started learning about pools- but after finding about elevated CYA levels, now I only use liquid chlorine.

Correct- the spillover runs non stop. As a result I have to add 20 oz of acid per week to keep the PH down.

Would adding the spillover function via the dip switch solve that issue while continuing to circulate the spa water?

One other feature I would like to achieve is to add some spillover ability while using spa mode. Right now- in spa mode it does 100% spa suction and return. So what happens, is when more people enter or leave the spa, or if water splashes out, the spa water level drops a lot and has no way to refill until I go back into spa mode. Any advice on that issue is appreciated as well

Thank you!

 

[ajw22]

I replaced the water temp sensor today and the new one is reading 4 degrees less than the old one. So- with the temp calibration at -4 it is reading spot on now and consistent with digital thermometers and also the heater thermometer.

Great! One problem fixed.

Would adding the spillover function via the dip switch solve that issue while continuing to circulate the spa water?

Running the spillover scheduled twice a day will reduce the rate of your pH rise and require less acid. Give it a try for a while and see what difference it makes.

You do not continue to circulate spa water continuously. You schedule the spillover to run twice a day. I run my spillover at 9AM for 15 minutes and 2PM for 15 minutes. That refreshed the spa water with pool water.

One other feature I would like to achieve is to add some spillover ability while using spa mode. Right now- in spa mode it does 100% spa suction and return. So what happens, is when more people enter or leave the spa, or if water splashes out, the spa water level drops a lot and has no way to refill until I go back into spa mode. Any advice on that issue is appreciated as well

Right now you have two modes - POOL mode or SPA mode.

You can get water into your spa now by changing to POOL mode for a few minutes and then switching back to SPA mode.

With SPILLOVER enabled you will have a third mode that suctions from the pool skimmer and returns water to your spa. You can switch from SPA mode to SPILLWAY mode for a few minutes to add water to your spa then switch back to SPA mode.

 

[poolman112]

Ok- So I set the dip switch 3 to on. Now I see the spillover option on the app. When i activate it, it is a total waterfall as you noted. However, when i turn it off, there is still water overflowing. Here is the image of the valve with the spillover off

 

[ajw22]

However, when i turn it off, there is still water overflowing. Here is the image of the valve with the spillover off

Now you need to adjust the cam on the actuator so that the valve is 100% OFF to the spa when in POOL mode.

Valve Actuators - Further Reading

www.troublefreepool.com