Hayward Heater b0 Code

sean-florida

Member
Aug 27, 2021
5
Florida
Yes, I've read other similar post - need additional guidance.

My Hayward 250 heater hooked up to Prologic won't turn on. It's on but just says b0. It's just not doing anything.
Now the back story.
About 6 months ago I noticed the display on the heater was missing the top clear layer and rain got into it (seems isolated to display/keypad board, not the main board).
Since the display board seemed mostly okay (there was some traces that burned the top layer of PCB, but they weren't broken/cut - very minor; tested for continuity), I bought a replacement keypad membrane and replace it and it worked. I could click Mode and switch between standby, pool, and spa. Fast forward - tried to heat the spa and nothing. I checked the heater - no error codes or anything, just b0. The mode button isn't work. I held down Mode + Down arrows and nothing except after 10+ seconds, I get the 56/5b error which means stuck button, so I know the buttons are functional. The Service & Heat indicators don't light up either (which I think is normal when it's not doing anything).
Other than the obvious "replace the display board", is there anything else that could lock out the keypad from working? I toggled power to the heater, nothing. I am testing when the pump is on, otherwise it shows L0 for lack of water pressure.

Appreciate any help - thanks!
 

ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
29,650
Northern NJ
Pool Size
35000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-60
Welcome to TFP.

b0 code simple means the heater is being controlled by the remote 2 wire connection to your Prologic and will not respond to the keypad controls


You need to diagnose if the heater is not getting the command to turn on from the Prologic or if the heater refuses to start when commanded.

You have a multimeter?

You need to check if the heater control relay in the Prologic closes when you call for heat. Do a continuity test on the relay pins.

If the relay is properly opening and closing then check the 2 wires for continuity from the Prologic to the connections in the heater.

If the connection to the heater is good then I would jumper the remote connections at the heater and see if it turns on. If it does not turn on then we know the problem is internal to the heater.

Get that far and report your results.
 

sean-florida

Member
Aug 27, 2021
5
Florida
Welcome to TFP.

b0 code simple means the heater is being controlled by the remote 2 wire connection to your Prologic and will not respond to the keypad controls


You need to diagnose if the heater is not getting the command to turn on from the Prologic or if the heater refuses to start when commanded.

You have a multimeter?

You need to check if the heater control relay in the Prologic closes when you call for heat. Do a continuity test on the relay pins.

If the relay is properly opening and closing then check the 2 wires for continuity from the Prologic to the connections in the heater.

If the connection to the heater is good then I would jumper the remote connections at the heater and see if it turns on. If it does not turn on then we know the problem is internal to the heater.

Get that far and report your results.
Wow, what a amazing response, thank you.
I do have a multi-meter. I figured it had something to do with the Prologic - relay sounds like a logical place to check. Will report back tonight!
 

sean-florida

Member
Aug 27, 2021
5
Florida
New update:
The wire does have continuity on both ends (ProLogic and Heater all the way to the board). Here's where I think the problem lies - I'm not getting 24v. I'm assuming 24v should be coming out of connector "Sensor Sel. Switch" ?
Does the keypad by chance have a say in if 24v gets delivered? Or any other sensor that may halt the 24v?


I have a h250fdn with control board f0059-476200. (I unplugged the connector for the picture - it was plugged in :) )
 

Attachments

  • IMG_3072.jpg
    IMG_3072.jpg
    527.7 KB · Views: 2
Thread Status
Hello , This is an inactive thread. Any new postings here are unlikely to be seen or responded to by other members. You will get much more visibility by Starting A New Thread