Hayward H250- 15 years old- throwing a LO code- will not reset

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Nashvillejoe

Nashvillejoe

Gold Supporter
Apr 14, 2013
119
Nashville
Pool Size
20000
Surface
Vinyl
Chlorine
Salt Water Generator
SWG Type
Hayward Aqua Rite (T-15)
So i have looked through a couple of the threads and didn’t see a solve- apologies in advance if there is something i missed.

I was hoping to get another year out of this guy-

i replaced the heat exchanger and a couple of the transisters about 2 years back and everything was going fine with it……. I run the pool year round so i have heat on in the fall - spring- and i run it at its lowest setting……. Nashville is pretty mild 360 days a year.

I tried to fire it a few weeks back and it would try to fire for about 90 sec and then error - after doing that for a bit- now it just flashes LO with the service light on.

I have a new variable speed Hayward pump that i keep at about 65% top speed but mostly run it about 50% - i was thinking it might be the flow switch……

2 questions…..
is there a way to reset the error code- (my unit is 2007 ish)
What is part number for flow switch replacement -


bonus: anyone else have any ideas……. You can see its old and pretty worked ……
 

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99% of the time LO can be a problem with the pressure switch which is located in the upper right hand side of the heater under the top front panel where the display is at. Locate it, remove the two wires from it and using another wire, jumper the two of them together and try the unit. FDXLWPS1930 is the part number for the flow switch. You can also find universal ones usually on Amazon.

You can power reset the unit by turning off the breaker to the unit and back on again.
 
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ps0303 said:
99% of the time LO can be a problem with the pressure switch which is located in the upper right hand side of the heater under the top front panel where the display is at. Locate it, remove the two wires from it and using another wire, jumper the two of them together and try the unit. FDXLWPS1930 is the part number for the flow switch. You can also find universal ones usually on Amazon.

You can power reset the unit by turning off the breaker to the unit and back on again.
Click to expand...
i jumpered the wires that i removed from the sensor power cycled the unit and fired it up …… same error LO
I then jumpered the two contacts on the sensor- in case i wasn’t reading your post properly and same error message

so it appears its not the flow switch ……..
 

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Last edited:
ajw22 said:
I think this is your manual - https://hayward-pool-assets.com/ass...ries-millivolt-owners-manual.pdf?fromCDN=true

Page 24 says LO is Limit string open. Not a flow problem.

Page 31 and on describes the limit switches. As a test you can jumper each switch to find out which one is faulting.

See page 38 for a chart with the possible causes of the LO code.

Page 43 has part numbers.
Click to expand...
Gonna swing by lowes and grab some jumpers- i do have a millimeter- So i can test all that when i get back this afternoon - thanks for taking the time to post it
 
These are limits that might be open.

1637090624255.png
1637090712053.png
1637090477826.png
1637090526286.png

Hayward H Series Pool and Spa Heater Temperature Limiters Kit - HAXTLK1930 - INYOPools.com

H-Series Temperature Limiters Kit
www.inyopools.com www.inyopools.com

6223-81.jpg
 
JamesW said:
These are limits that might be open.

View attachment 382234




Hayward H Series Pool and Spa Heater Temperature Limiters Kit - HAXTLK1930 - INYOPools.com

H-Series Temperature Limiters Kit
www.inyopools.com www.inyopools.com
Click to expand...
Upper left switch seems bad- the reset switch- all the switches zero out with the MV reader- except that one- it goes to all zeros with a 1 blinking where the 10 would be - i used the V reading on the millivote and it was scrolling through a bunch of numbers……. I ordered the 3 switches and will see about resetting them
 

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JamesW said:
View attachment 382285
1637091152268-png.382240
Click to expand...
Okay i get it- i have to remove the top vent enclosure to access it- and if that guy is bad then perhaps thats giving me the LO ….\

1) one question even if that Hi Limits sensor was off- wouldn’t i be able to jumper the ends and have it fire up…….
2) So a second question….. my pressure sensor that you had me jump the two cables……. One of the connector stems is loose - so i am thinking i should just replace that sensor….. its the one on the upper right corner- that has wires that connect to the outside sensor(i have circled it in the photo). That connector post is loose….

i have another question- i recently had a variable Hayward pump put in- i run it about about 60%, is it possible that I’m not putting enough volume/pressure through the line…..??
 

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Nashvillejoe said:
i have another question- i recently had a variable Hayward pump put in- i run it about about 60%, is it possible that I’m not putting enough volume/pressure through the line…..??
Click to expand...

That is easy enough to test. Just turn up your pump and try the heater.
 
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