Hayward pro logic board repair

Jump to latest Follow Reply
G

Georgia088

Member
Jun 29, 2013
17
Hello and thanks in advance for any help!

I have a Hayward pro logic pool pump controller. It has a controller that has buttons to turn the filter on (220v), pool lights, and two AUX switches

The display with the buttons is some sort of micro controller that connects to the main board. There are several small relays on the main board. Coming off of the main board are 8 wires that go to 4 independent large relays. These large relays have a 24 vdc coil and are what activate to turn the pool pump, lights, and two AUX devices on.

All 4 relays are receiving 24vdc all the time. As soon as the controller is powered up 24vdc is going through to the large relays and activating them. Making my pump, lights, etc. ON all the time.

I am assuming some of the small relays on the board are supposed to be activated by the button press on the display screen. Then, they activate the coil of the bigger relay? Does that sound logical?

The button presses seem to be working properly as you can hear an audible beep when they are pressed and the display reads “pool lights on” etc.

After doing a little research, I have identified two of the chips near all the small relays as mic5841YN. These are apparently relay driver chips. I found this spec sheet:

ww1.microchip.com 11

mic5841.pdf 1​

163.60 KB

I am not sure how to test them though…. Or even if I am headed in the right direction. Has anyone else had issues with these chips?

Again, thanks for any help!
 

Attachments

  • 0F9BE1C2-E682-4B78-AA01-6DBA3B5AB275.jpeg
    0F9BE1C2-E682-4B78-AA01-6DBA3B5AB275.jpeg
    581.8 KB · Views: 22
I have sent them an email. I wouldn’t mind giving it a shot, but I am not sure how to test the mic5841 relay driver. I believe this is what is faulty. I was hoping to find a schematic or someone with experience troubleshooting the board. Thanks again!
 
Hey just saw your pm...

As far as the relays go... I'm pretty sure the small relays control the valves, not the large relays. I'd bet that all the relay coils are driven by the mic5841 chips.

I haven't repaired any Hayward units, I've only guessed at potential problems by looking at photos of the board. In the post I think you found me in, it ended up being a bad relay... I think the relays are all soldered in so with the board powered off you could energize/de-energize the relay coils with your own power source to check them.

i'm thinking the 24v you noticed may be a red-herring unless you're seeing 24v across the relay coil (i.e. put your test probes on either side of the coil, not at the driver output pin and ground)

The mic5841 has a serial input that drives an 8-bit latch to control a Darlington array at the output that "sinks" current... the latch pulls the corresponding output pin to ground or to whatever is connected to the "K" pin. I don't have a schematic for the hayward board so you'll need to verify how the relays are wired to the drivers and what K is connected to... but normally, one side of the relay coil would be tied to the "K" pin which is also connected to 24v, and the other side of the coil is connected to the driver output pin. When the output goes low it puts 24v across the coil and it turns ON.

So, measure the voltage across the coil which would also be from the output pin to the K pin if they're wired up as described above. If the relay is ON with 0v across the coil, it's stuck. If you don't get 24v across the coil when the relay should be ON, or 24v when the relay should be off... the driver is probably bad.

I hope that's helpful?
Tom
 
That is awesome help! I have verified that the large relays are good. I actually have a separate 24v supply connected to a “smart plug” (controlled by Alexa) that I can turn the relay (pump) on by turning the “smart plug” on which turns the 24v supply on and it works. So, I know the large relay works.

I think your test will allow me to test the actual small relays and determine if the small relays are bad or if it is the driver. I will post back and let you know I really appreciate it!!

edit: I reread your post. The large relays that I am referring to are not soldered to the board. I think (very well could be wrong) what you are saying does happen, but those relays are actually activating the larger relays that are not soldered to the board (that I have connected to “smart plug”). I am not sure if those smaller relays are bad or the driver.

The large relays I am referring to are the tan colored at the bottom of the picture.
Thanks!
 

Attachments

  • B4652DB6-285C-4D0A-80D3-98FFDAB6347D.jpeg
    B4652DB6-285C-4D0A-80D3-98FFDAB6347D.jpeg
    581.8 KB · Views: 13
Last edited:
ahh ok cool, I didn't notice the two tan Omron relays there before - but you said those are working? (I actually didn't know the hayward could drive external relays at all) ;)
 
Yes, there were actually 4 omron relays in the panel. The picture only shows two. I removed the other two. They were for the two aux switches on the board. They are all four are working. I can put 24v on the coil terminals of all four and all four activate. I am able to control the pool pump now by disconnecting the wires coming from the main board to the coil of the large omron relay. I can then connect the coil of the same relay with a separate 24v supply and when it is powered on, the relay activates. Powered off, the relay deactivates.
The problem is all four omron relays when connected correctly from the main board are receiving 24v across the coil all the time so they stay activated all the time. So, I believe whatever is supplying the coil voltage to the omron relay (which I think you’re test will help me determine) has stuck closed and is sending 24v all the time to the large tan omron relays. I hope that makes some sort of sense.

I believe the faulty component is going to be the mic5841 driver. I just can’t imagine all four small relays going bad at once, but I will have to test. My other question is: There are two mic5841 drivers side by side. Does each one control two relays? Or does one of them control all 4 and the other controls some other function with in the board?

Again, I really appreciate the help!
 
I'm betting on the drivers being faulty too... those small relays are probably fine - the only bad one I've ever had to replace was physically damaged, like it was hit with something.

I bet the drivers are just for the relays. Each driver has 8 outputs, and I think there are 9 relays on the board itself plus the 4 external ones you mentioned, and it also looks like there's room for an additional 4 (maybe depending on the system?). That makes 17, but there are only 16 driver outputs. The 9 on-board relays may not all be controlled by the drivers but I bet at least the small ones are (You'd have to trace out the coils with a multimeter to be sure). The outputs can also be combined to drive larger loads but I'd be surprised if they did that with these relays - so it's probably one driver output per relay.
 

Enjoying this content?

Support TFP with a donation.

Give Support
oh, i forgot to add... when you replace the drivers you might want to install sockets first. might never have to change them again, but it's cheap insurance. (the pentair drivers are socketed)
 
It’s a shame these drivers aren’t socketed! I have dabbled in electronics, but I am not sure that I can desolder the dip chip without doing damage to the board.
To be honest, I am kind of liking having the ability to control the pump via Alexa or my phone. I can set the timer for the pump up through the Alexa interface. I probably would have done this before now had I known how it worked and that the SWG didn’t really “need to know” when the pump was running and when it wasn’t. I assume it determines this with the flow switch?
I am curious if it is the drivers or the relays, but I feel pretty confident that it is the driver. I will probably still do your test to determine, but unless there is a reason not to continue using Alexa to trigger the relay/pump separate from the main board; I will probably continue using Alexa.
Thanks again!!
 
yeah, it's a shame they didn't socket them!

The flow switch is there to prevent the cell from generating chlorine when there's no - or insufficient - flow... otherwise gas can build up in the cell, potentially causing damage and/or injury.

Is your swg powered up all the time or only when the pump is on? (i have a hayward swg connected to my intellitouch, and it's only on when the pump is on)
 
ogdento said:
yeah, it's a shame they didn't socket them!

The flow switch is there to prevent the cell from generating chlorine when there's no - or insufficient - flow... otherwise gas can build up in the cell, potentially causing damage and/or injury.

Is your swg powered up all the time or only when the pump is on? (i have a hayward swg connected to my intellitouch, and it's only on when the pump is on)
Click to expand...
To be honest, I’m not sure. I’m not looking at it right now, but the only adjustment that I can think of is the percentage of “power” the SWG is putting out.
I assumed that once the pump went off the flow sensor “told” the main board to turn the SWG off. But I really don’t know how it works.
Thanks!
 
You must log in or register to reply here.
Thread Status
Hello , This thread has been inactive for over 60 days. New postings here are unlikely to be seen or responded to by other members. For better visibility, consider Starting A New Thread.
Top Bottom
Back
Jump to latest Follow Reply