Hayward H250 16 years old……. Solid service light- blinking LO error…..

Nashvillejoe · May 29, 2022

So i havent used my heater in about a 8 mo- last year i installed a new heat exchanger and used it for most of 2021. By the end of the year we decided to refurbish the pool so i didn’t use the pool or heater over the winter months….. finished refurbishing the pool and and tried to fire up the heater and i get the solid service light and the blinking LO….

I do have a sensor issue in the call Omni logic app no flow- could that be causing my heater to not working- my sense is no - that error is most likely from me shutting the system down to swap the T15 and filters(?)

as i said the exchanger is about a year old and i have a TriStar Variable so i know i am getting plenty of water, the exchanger is new and i can control my heater from the OmniLogic app……

My first thought …… is there a way to reset the panel?? (When i power off the heater- my pump stops and then will restart….. so that sensor is functioning..

What is best way to isolate the sensor that is causing the fault…..

thanks in advance!!

Poolbreh · May 29, 2022

LO seems to be the pressure switch, increase speed on the heater circuit. Clean the filter if necessary.

Nashvillejoe · May 29, 2022

Poolbreh said:
LO seems to be the pressure switch, increase speed on the heater circuit. Clean the filter if necessary.

New filters installed yesterday and running a Tristar at 90% - is it and instantaneous reading - maybe the flow sensor is corroded - can I bypass the circuit and just tie the two sensor wires ??

Poolbreh · May 29, 2022

All pressure switches are fairly similar usually you can see the piston open will the pump is on and it hits the microswitch to close the loop. You can bypass it but it should only be done for testing.

Nashvillejoe · May 29, 2022

Poolbreh said:
All pressure switches are fairly similar usually you can see the piston open will the pump is on and it hits the microswitch to close the loop. You can bypass it but it should only be done for testing.

I was only going to use it for testing after reading some of the threads I’m thinking it’s probably just time to buy a new heater

Nashvillejoe · May 29, 2022

Nashvillejoe said:
I was only going to use it for testing after reading some of the threads I’m thinking it’s probably just time to buy a new heaterView attachment 416808

Can I just close the loop with the blue and red wire??

For testing

Poolbreh · May 29, 2022

The pressure switch looks like it’s behind front panel. You can also flush tubing and try cleaning pressure switch if it’s not opening. Don’t adjust it though. Instead of jumping it you can use a flat head and engage microswitch on the pressure switch. If the microswitch is bad it will have to be jumped or tested.

Nashvillejoe · May 29, 2022

Okay so i clipped the wires and bypassed both sensors and the unit fired right up - working perfectly

so does anyone know what sensors those are - i figured i would just replace them both

Poolbreh · May 29, 2022

Best to verify with your manual but that came up as Hayward’s h250 manual. Hls 135 hls 160. It’s best to jump the quick disconnect terminals with a wire instead of cutting wire.

Nashvillejoe · May 29, 2022

Poolbreh said:
View attachment 416838 View attachment 416839
Best to verify with your manual but that came up as Hayward’s h250 manual. Hls 135 hls 160. It’s best to jump the quick disconnect terminals with a wire instead of cutting wire.

I think I found the culprit - its that white sensor…… interesting though….. i thought there was a flow sensor that opened and closed with the flow…. And everything i pulled off the manifold is just pieces that have no mechanism to affect flow- it seems like most of the holes are filled with caps….… i am guessing that one pressure switch is it

ajw22 · May 29, 2022

Nashvillejoe said:
I think I found the culprit - its that white sensor…… interesting though….. i thought there was a flow sensor that opened and closed with the flow…. And everything i pulled off the manifold is just pieces that have no mechanism to affect flow… i am guessing that one pressure switch is it

That is a pressure switch not a flow sensor.

Nashvillejoe · May 29, 2022

ajw22 said:
That is a pressure switch not a flow sensor.

Nashvillejoe · May 29, 2022

i don’t see a flow sensor anywhere on my heater…… i do see one in my piping after the salt cell - is it possible there is supposed to be a flow sensor on this and the previous owner removed it and replaced it with a cap ??

Nashvillejoe · May 29, 2022

This is the only mechanical attached to the manifold and as you noted its clearly a pressure switch!!

Poolbreh · May 29, 2022

The no flow on the Omni logic is probably related to your salt system. Your omnilogic doesn’t communicate with the heater in that way. It only tells the heater to turn on or off based on the omnis temp sensors and demand. LO is a pressure issue, not exactly sure why it would fire with hls bypassed.

ajw22 · May 29, 2022

Nashvillejoe said:
i don’t see a flow sensor anywhere on my heater

Pool heaters use pressure switches, not flow switches, for water flow.

Nashvillejoe · May 29, 2022

Poolbreh said:
The no flow on the Omni logic is probably related to your salt system. Your omnilogic doesn’t communicate with the heater in that way. It only tells the heater to turn on or off based on the omnis temp sensors and demand. LO is a pressure issue, not exactly sure why it would fire with hls bypassed.

If the relay on the pressure switch is shot- than it wont complete the circuit so even though there is sufficient pressure- the relay will read- no pressure-

so i will swap out that part and i would bet a nickel i will be good to go !!!

thanks so much for helping - i will post the resolution after i track down that part

Nashvillejoe · May 29, 2022

These hi limit switches have a fair amount of copper oxidation on them….. at first i thought it was some kind of copper plating and then i realized its most likely oxidation so just wanted to confirm before i took steel wool to the base and cleaned off the oxidation

ajw22 · May 29, 2022

I don't think the oxidation has any impact on their functioning. The electrical contacts need to be clean and the temperature controlled switch is all internal to the sensor.

Poolbreh · May 29, 2022

LO is a limit string so it checks the loop of multiple sensors before firing. One of those hls must of been open upon LO test that’s probably why it fired. If the pressure switch engages microswitch, I would jump or test each hls individually one of them is open. For future reference don’t cut the wire just use the quick disconnects and bridge with a small piece of wire.

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Hayward H250 16 years old……. Solid service light- blinking LO error…..

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