Temperature reading 78F on all sensors

cptkirk

Well-known member
Jul 29, 2018
107
Miramar Beach, FL
Pool Size
20000
Surface
Plaster
Chlorine
Salt Water Generator
Have a salt water pool with Hayward Omnilogic controller. Yesterday for no apparent reason my system went into freeze protect on both the filter pump and water feature pump even though the air temperature was in the 60's. Tried power cycling the controller a couple of times to no effect. I turned off the water feature pump at the electric panel since I didn't want it running but left the filter pump on since I run it continuously anyway. This morning my air temperature and water temperature in the controller are both reading 78F currently, but the air temp is mid 60's and water temp is low 60's. Nothing seems wrong with the sensor wiring all nice and snug, no corrosion or visible breaks. Both had been working previously. Any hints as to what might be going on?
 

Dirk

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TFP Guide
Nov 12, 2017
8,624
Central California
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12300
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Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
Not really. Sensors can go bad. Hard to believe two would both go bad at the same time. Also, some pumps have their own freeze protection sensors and circuitry built in, independent of the automation controller's freeze protection components. The pump's will override the controller's. But also hard to believe both of those would malfunction at the same time (assuming they both have their own). Kinda stumped, sorry. Sounds like a possible controller motherboard malfunction in its temperature circuitry or firmware. That's really the only thing I can think of that would explain all the failures all at once.

Until someone else here chimes in, you might try Hayward's tech support to see if they've heard of this happening.

BTW, welcome to TFP! You might work on your signature and fill in your pool specs and equipment list. It can help our experts with answering your questions. Mine is a good example.
 
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cptkirk

Well-known member
Jul 29, 2018
107
Miramar Beach, FL
Pool Size
20000
Surface
Plaster
Chlorine
Salt Water Generator
The system is configured to send me emails when it gets alarm conditions. I just looked at the alarm chain from yesterday, it was quite abnormal. First it sent separate temp sensor open alarms on both the water and air at 5:40 pm, followed by alarm clear messages for both at 5:42, followed by a repeat of both alarms at 5:45. It also gave me a low T-Cell Temperature alarm at 6:10. None of these alarms is currently present. But the air is currently 79, water 78, and my T-Cell diagnostics don't show any data whatsoever.
 

Dirk

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Nov 12, 2017
8,624
Central California
Pool Size
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Plaster
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Salt Water Generator
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Pentair Intellichlor IC-40
Sounds like more motherboard evidence... If I'm understanding you, the T-Cell temp anomalies are in addition to two different other sensor-analyzing anomalies. There must be a motherboard component (hardware or firmware or both) that receives data (probably resistance/ohms readings) from all the various sensors, and then translates that into bits and bytes used by the motherboard's programming. The motherboard is acting correctly on the data, it's just being fed inaccurate data. And since it's acting on three different sensors, it has to be a common component. Which (I'm only guessing) has to be on the motherboard. That common component has failed or gotten corrupted somehow. Otherwise, someone is sneaking out to your pad and spraying down your gear with liquid nitrogen when you're not looking!

If the problem is firmware, and not hardware, and if the motherboard firmware can be flashed (updated or reloaded), that could conceivably be a fix. Like reinstalling the operating system on a computer sometimes fixes things. But I wouldn't know about that, or if the process is available to the end-user. Hayward would.
 
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cptkirk

Well-known member
Jul 29, 2018
107
Miramar Beach, FL
Pool Size
20000
Surface
Plaster
Chlorine
Salt Water Generator
Yes, the T-cell alarms are in addition to the other alarms. The T-cell low temp alarm cleared at 11:26 pm last night. The T-cell diagnostics were showing data earlier today (also with a temperature near 78F, even after I turned the heater on which should have caused the temperature to rise in the cell), but are no longer showing anything (no salt, no temp, nothing).
 

ajw22

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Jul 21, 2013
24,657
Northern NJ
Pool Size
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Chlorine
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SWG Type
Pentair Intellichlor IC-60
You can test your temperature sensors using a multimeter measuring the ohms. Read Temperature Sensors - Further Reading

78 degrees is around the temperature that many devices default to if the temperature sensor is open.

Sounds like you have a few spurious things going on with your board. Hayward boards have been known to overhat and burn out components and solder traces. You might want to remove the board and examine it closely for any signs of overheating. See Hayward Aquarite SWG - Further Reading for examples of what burnt boards look like.

Post pics of your system showing the boards and wiring.
 

cptkirk

Well-known member
Jul 29, 2018
107
Miramar Beach, FL
Pool Size
20000
Surface
Plaster
Chlorine
Salt Water Generator
Water sensor read about 12K ohms, air sensor around 8k ohms. Guess that makes sense since the air is about 10 degrees +/- warmer than the water. No visible damage to the motherboard I could see (I didn't remove it to inspect the backside though). The T-cell diagnostics are working now, except that the cell temp is showing 77.4F, very close to other two sensors. I presume that is an indepedent sensor through the T-cell connector?
 

cptkirk

Well-known member
Jul 29, 2018
107
Miramar Beach, FL
Pool Size
20000
Surface
Plaster
Chlorine
Salt Water Generator
Also looking back through the alarm emails, I see I got some MPP Comm Loss errors earlier in the day before the temperature sensor alarms. These are cleared now and the MPP seems to be cycling normally (power LEDs on, processor LED blinking at 6 sec on/6 sec off as normal).
 

cptkirk

Well-known member
Jul 29, 2018
107
Miramar Beach, FL
Pool Size
20000
Surface
Plaster
Chlorine
Salt Water Generator
Those numbers on the sensor readings are probably not exact, I was paying more attention to whether it was open or not. The actual water temp is in the neighborhood of 60F, air temp about 71F currently (but its got some sun so might be reading a bit higher). The controller says water temp 78, air temp 79, cell temp 77.4 at the moment.
 

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cptkirk

Well-known member
Jul 29, 2018
107
Miramar Beach, FL
Pool Size
20000
Surface
Plaster
Chlorine
Salt Water Generator
For grins I updated the MSP and MPP to the latest firmware. There is a new feature that lets you calibrate the air/water temp sensors, but basically it just lets you select an offset value if your readings are off a few degrees from what they should be. So for example my water temp now reads 68 instead of 78, but it's still "stuck" at that value. The SWG cell temp still reads 77.4. Will try to contact Hayward to see what they have to say.
 

cptkirk

Well-known member
Jul 29, 2018
107
Miramar Beach, FL
Pool Size
20000
Surface
Plaster
Chlorine
Salt Water Generator
Haven't made any real progress on this issue. Hayward so far has not been any real help. I had some warranty work done on my Omnilogic this past June, and the MSP, MPP, and power supply were all replaced (it really was a power supply issue). I am now outside of the 3-year warranty period on the unit, and although the new MPP would be in the one-year warranty period on the part if I had purchased it, that apparently does not apply to my situation.

For grins, I tried reseating the sensor terminal block and the salt cell connector block, and also moving the air temp sensor to a vacant sensor location (and reconfiguring the location in the Omnilogic), but get the same results. The Omnilogic detects open loop when the sensor is not connected, but always reads 78 (or close to that) on all temperature sensors (including the one in the salt cell) when the sensors are connected regardless of actual temperature. I tested all three sensors with a meter, and they all look good (that is, the resistance was about what you would expect given the actual temperatures). Basically, the Omnilogic thinks the resistance is always around 10k ohms when the resistance is actually some other value.
 

cptkirk

Well-known member
Jul 29, 2018
107
Miramar Beach, FL
Pool Size
20000
Surface
Plaster
Chlorine
Salt Water Generator
Update: I ordered and installed a new MPP, that fixed my issues. I was a little freaked out at first because nothing was working except the pump, but then realized I had to reconfigure all the sensors and relays. After I did that, all the temps are reading normally, salt cell diagnostics show correct info, and heater is functional.
 

KevJB

Member
Apr 28, 2021
11
Atlanta, Ga.
FYI - Some comments. For $14 I will keep a spare sensor and, if in doubt, swap to test.
Omnilogic - Adding Additional Temperature Sensor | Trouble Free Pool