Jandy 2 wire remote question

[bagsofcole]

Hey guys. I’m hooking up my jandy jxi260p to a home brew automation and I have a question about the 2 wire remote. What exactly is the signal to switch on and off the heater? I see 24VAC all over the internet but I let some smoke out of the heater when I gave the pool and common terminals 24VAC. It still works but I’m afraid I fried the remote circuit of the Jandy. I’ve read the jandy manual, went through the mento to select TSAT, and even the board says 24VAC loop next to the remote terminal.

Other than this minor hiccup, this set up is pretty cool, I’ll share it onice it’s all up and running. Big props to to neilroeth on Instructables. He made it so easy, even a caveman can do it. Here it is if interested.

Replace Your Pool and Spa Controller With Raspberry Pi, Arduino, Node Red

Replace Your Pool and Spa Controller With Raspberry Pi, Arduino, Node Red: In this Instructable I will describe how to build a pool and spa controller that controls a pump motor, multiple electric valve actuators, lights, a cleaner, air blower, and heater. It also measures the water and air...

www.instructables.com

 

[ajw22]

You don’t put 24V AC on the fireman’s switch heater control. The voltage is supplied by the heater. You just close the circuit through the relay on the automation. It just needs a SPST switch to close the circuit and run the heater.

 

[bagsofcole]

Thanks ajw, now you tell me! . So any chance you or anyone out there knows what this little square black thing that I cooked is? A Field effect Transistor perhaps? It has the numbers BBE G3 551 stamped on it and is position TVS6.
Think the remote will work if I use the com and spa terminals instead of com and pool? The manual says to use pool...
Another possible other option is to steal the unknown component from TVS7, I’m just guessing that one is for the spa port of 3 wire remote and I’m only using the 2wire option.
Believe it or not the heater still works and cycles on and off as needed, but now that I’m just closing the remote for loop with a switch, the heater won’t shut off.

 

[ajw22]

The only difference between POOL and SPA on the heater is which thermostat setting the heater uses.

Some members have had good experiences with BP Engineering, Inc. repairing their Jandy boards. See if they can help you with the component you fried.

 

[PoolGate]

A used Jandy main board, especially an older board, is pretty cheap on ebay. I would just get a used one.

 

[MSchutzer]

That part you smoked is a TVS (transient voltage surge) protection diode. It's purpose is to clamp a transient voltage (think lightening or static induced voltage) across the diode before the high transient voltage can damage the circuitry after the diode. These are typically put across input terminals to protect the board from damage. It seems like the diode did it's job as it shorted and smoked when you put 24 VAC continuously across it. The diode is likely open now, but sometimes they can fail shorted also.

That's a part made by ST Microelectronics, let me look around a bit and see if I can find the exact part number for you. Typically a TVS diode runs about 50 to 60 cents in quantity 1 and is should be readily available at DigiKey Electronics if I can find the full part number. I'll get back to you shortly.

Mark

 

[MSchutzer]

Hi,

Here's some information on that part you fried. It is an ST Microelectronics TVS diode part number SMBJ12CA-TR. The base part number is SMBJ12CA, it's a 12v Bidirectional TVS diode. The -TR on the end just calls out tape and reel packaging.
You can order the part from DigiKey Electronics (www.digikey.com) under Digikey's part number 497-3002-1-ND and they are 39 cents in quantity 1. Below I have attached the marking legend for that diode and the marking code from ST Micro's SMBJ datasheet. I've also attached a screen shot of Digikey's page for that part. Just search for 497-3002-1-ND on Digikey's opening page and it will pop right up.

I hope this helps.

Mark

 

[MSchutzer]

One more thing, since your heater is enabled all the time the TVS diode likely failed shorted, keeping the heater enabled.

If you have a soldering iron you can remove that part by heating each end and while the solder is hot you can use a pair of tweezers to lift that end of the part from the pc board. Moving the iron from one end to the other you can work each end off the board. If the heater enable works normally with the part removed then the part failed shorted.

That part is not needed for the enable line to work, it is strictly there to provide protection from over-voltage and transients on the input lines.

I hope this helps,

Mark

 

[bagsofcole]

One more thing, since your heater is enabled all the time the TVS diode likely failed shorted, keeping the heater enabled.

If you have a soldering iron you can remove that part by heating each end and while the solder is hot you can use a pair of tweezers to lift that end of the part from the pc board. Moving the iron from one end to the other you can work each end off the board. If the heater enable works normally with the part removed then the part failed shorted.

That part is not needed for the enable line to work, it is strictly there to provide protection from over-voltage and transients on the input lines.

I hope this helps,

Mark

Mark, you have been 100% correct. I posted a pic on Reddit and got the exact same response. The obviously fried TVS was shorted and when the heater was in remote mode it was on all the time. I remove them both and now it won’t come on at all in remote mode, only works in remote off mode. I’m thinking my archaic soldering skills might have removed part of the circuitry on the board so this morning I’m trying to just dab a little solder on each of the four contact points to see if that completes the connection. Thanks for the replies, I’ll keep you all updated.

 

[MSchutzer]

Another thought, it might not have been your soldering skills at issue. Since the TVS diode shorted you would have large currents flowing on the PC board trace between the pool terminal on the connector and that TVS diode (TVS6). 24 VAC at an amp or better may have burned up that small PC board trace and caused it to go open. Turn the PC board over and see if you can see the trace connecting to the pool terminal of the connector. Does it look like it got hot, or possibly melted open? If this is the case you may have to patch a small wire from the pool terminal of the connector to the upper terminal (in your pictures) of TVS6 to restore remote operation.

And since you didn't have anything connected to the spa terminal of the connector I would expect that TVS7 and spa remote input is still functional currently.

I hope this helps,

Mark

 

[bagsofcole]

Another thought, it might not have been your soldering skills at issue. Since the TVS diode shorted you would have large currents flowing on the PC board trace between the pool terminal on the connector and that TVS diode (TVS6). 24 VAC at an amp or better may have burned up that small PC board trace and caused it to go open. Turn the PC board over and see if you can see the trace connecting to the pool terminal of the connector. Does it look like it got hot, or possibly melted open? If this is the case you may have to patch a small wire from the pool terminal of the connector to the upper terminal (in your pictures) of TVS6 to restore remote operation.

And since you didn't have anything connected to the spa terminal of the connector I would expect that TVS7 and spa remote input is still functional currently.

I hope this helps,

Mark

haha, I hit it with way more than an amp and that makes a lot of sense because I can’t find any conductor under where the TVS were, just a few strands of what I assume may have been the traces. Here are a couple of pics. where do you think the TVS6 goes to? Off to the left? I’ve circled the 3 scraps of potential traces. Think I should use #1? I imagine that one is for pool, and common has a piece of the TVS still on the board, so I should be good there.

 

[bagsofcole]

Another thought, it might not have been your soldering skills at issue. Since the TVS diode shorted you would have large currents flowing on the PC board trace between the pool terminal on the connector and that TVS diode (TVS6). 24 VAC at an amp or better may have burned up that small PC board trace and caused it to go open. Turn the PC board over and see if you can see the trace connecting to the pool terminal of the connector. Does it look like it got hot, or possibly melted open? If this is the case you may have to patch a small wire from the pool terminal of the connector to the upper terminal (in your pictures) of TVS6 to restore remote operation.

And since you didn't have anything connected to the spa terminal of the connector I would expect that TVS7 and spa remote input is still functional currently.

I hope this helps,

Mark

oh, and I let quite a bit of smoke out, so I'm sure those traces are toast... But like you said, since it was always on in remote mode, makes sense that the rest of the board works. And now that I removed the short (the dead TVS), makes sense it' open between the TVS6 position and the connector where I plugged in the remote wires.

 

[bagsofcole]

Another thought, it might not have been your soldering skills at issue. Since the TVS diode shorted you would have large currents flowing on the PC board trace between the pool terminal on the connector and that TVS diode (TVS6). 24 VAC at an amp or better may have burned up that small PC board trace and caused it to go open. Turn the PC board over and see if you can see the trace connecting to the pool terminal of the connector. Does it look like it got hot, or possibly melted open? If this is the case you may have to patch a small wire from the pool terminal of the connector to the upper terminal (in your pictures) of TVS6 to restore remote operation.

And since you didn't have anything connected to the spa terminal of the connector I would expect that TVS7 and spa remote input is still functional currently.

I hope this helps,

Mark

So you really got me thinking. After putting light behind the board and I think I can trace it. Fingers crossed.

 

[MSchutzer]

Yeah, the light behind the board makes it easy to see. It looks like the PC board pads came off the board for both TVS6 and TVS7 and that broke the connection that ran through the pads. That trace that comes off the pool terminal in the middle needs to get connected over to the pad on the bottom end of the 100 ohm resistor R6. The connection that goes to the Spa terminal of the connector needs to get bridged the bottom end of resistor R5. If you are careful you can use an Xacto knife and scrape the green soldermask off those traces to expose copper which you can solder to. It's probably easier to just run a jumper wire from the bottom terminals of the connector to the ends of the resistor pads.

Mark

 

[bagsofcole]

Yeah, the light behind the board makes it easy to see. It looks like the PC board pads came off the board for both TVS6 and TVS7 and that broke the connection that ran through the pads. That trace that comes off the pool terminal in the middle needs to get connected over to the pad on the bottom end of the 100 ohm resistor R6. The connection that goes to the Spa terminal of the connector needs to get bridged the bottom end of resistor R5. If you are careful you can use an Xacto knife and scrape the green soldermask off those traces to expose copper which you can solder to. It's probably easier to just run a jumper wire from the bottom terminals of the connector to the ends of the resistor pads.

Mark

Where do you think the com terminal of the connector needs to go? I was thinking the remaining piece of the TVS6 on the right? Or maybe the bottom of D13?

 

[bagsofcole]

Where do you think the com terminal of the connector needs to go? I was thinking the remaining piece of the TVS6 on the right? Or maybe the bottom of D13?

View attachment 175290

I GOT IT! Thanks MSchutzer!!! Worked as in picture from above!

 

[MSchutzer]

The common terminal is connected to ground and that’s still connected as you can see the connection on the bottom view of the board. So your blue wire jumper really isn’t needed.

Glad to hear its working now, good job!

Mark