Remote connection on Jandy LRZ Legacy Heater

madpsintst

Member
Jul 1, 2014
6
Mississauga, Ontario
I would like to control my Jandy LRZ Legacy heater using my existing home automation system. I notice in the heater installation manual (p. 23 linked below) that the main control board has a remote control connector with three pins labelled COM, POOL and SPA. Using my home automation system I can control a relay connected to this remote control terminal, but the manual does not provide any current requirements for the remote control connections. For example, does the heater turn on when 24 VAC is passed through the COM and POOL terminals? Or is this a contact closure detector such that the heater turns on by simply bridging the connection between the COM and POOL terminals? Or does this terminal have different requirements altogether? Perhaps there is an industry standard used in the pool heater industry that somebody can point me to?

Thanks in advance for any help or advice.

Link to Jandy Legacy manual: http://www.jandy.com/~/media/zodiac/global/downloads/h/h0299500.pdf
 

ps0303

TFP Expert
In The Industry
Jul 6, 2011
3,965
FL
The heater turns on when 24 VAC is passed through the COM and POOL terminals or the COM and SPA terminal.
 

madpsintst

Member
Jul 1, 2014
6
Mississauga, Ontario
The heater turns on when 24 VAC is passed through the COM and POOL terminals or the COM and SPA terminal.
I seem to have run into a problem. I connected the COM and POOL terminals to a relay which provides 24 VAC via a 200 mA power adapter. This is the adapter I used: http://ca.mouser.com/search/ProductDetail.aspx?r=553-WAU24-200

The heater did not turn on, but instead I could smell burning electronics. After killing the power I examined the circuit board, and it looks like a diode has been burned out. Here are photos of the board: http://macropodsoftware.com/lrz/heater_circuit_01.JPG and http://macropodsoftware.com/lrz/heater_circuit_02.JPG

I contacted Jandy tech support, and they confirm that I am supposed to pass 24 VAC through the COM and POOL terminals to engage the heater. The heater still works using manual controls, but I'm not sure what to do next to connect it to my home automation system. I am reluctant to replace the heater board only to fry the next one too. Any ideas what could have gone wrong? Did I pass too much current through the pins? I measured the power adapter voltage with a voltmeter and it reads 25.6 VAC.
 

Vinoh

New member
Apr 22, 2017
3
San Jose, CA
I seem to have run into a problem. I connected the COM and POOL terminals to a relay which provides 24 VAC via a 200 mA power adapter. This is the adapter I used: http://ca.mouser.com/search/ProductDetail.aspx?r=553-WAU24-200

The heater did not turn on, but instead I could smell burning electronics. After killing the power I examined the circuit board, and it looks like a diode has been burned out. Here are photos of the board: http://macropodsoftware.com/lrz/heater_circuit_01.JPG and http://macropodsoftware.com/lrz/heater_circuit_02.JPG

I contacted Jandy tech support, and they confirm that I am supposed to pass 24 VAC through the COM and POOL terminals to engage the heater. The heater still works using manual controls, but I'm not sure what to do next to connect it to my home automation system. I am reluctant to replace the heater board only to fry the next one too. Any ideas what could have gone wrong? Did I pass too much current through the pins? I measured the power adapter voltage with a voltmeter and it reads 25.6 VAC.
I've been wondering the same thing about my JXi heater. I think the COM supplies 24V so all that should be required is a relay (or switch) closure between COM and POOL or COM and SPA. Supplying a separate 24VAC to the COM line may have fried the component especially if it was out of phase with the internal voltage. Did you happen to measure the voltage on the COM line before hooking up your relay?
 

madpsintst

Member
Jul 1, 2014
6
Mississauga, Ontario
Unfortunately I didn't measure the voltage across those pins before connecting. I sure wish I had. I contacted Zodiac support and asked precisely this question. They gave me a vague answer that there needed to be 24V AC there, but did not specify if I needed to supply this current externally or just use my relay to connect the COM and POOL pins. When I asked for clarification, they would not answer but instead referred me to my "pool professional" to connect my heater to my home automation system. Very frustrating given that my pool installer has no clue how my home automation system works, and frankly given the quality of the work he did with my pool I wouldn't let him anywhere near my home automation system! If anybody else has a Jandy Legacy I would appreciate if you could measure the voltage at the COM pin. If there is already 24 V there, then it would indicate that I need to replace my controller board and try a different approach.
 

madpsintst

Member
Jul 1, 2014
6
Mississauga, Ontario
Here is what I have learned:
- set the remote setting to HI-LO-COM as per the user manual
- to turn on the heater remotely using a relay, simply bridge the connection between the COM and POOL terminals
- DO NOT provide 24 VAC to the connector labelled COM POOL SPA terminals. If you do, you will FRY YOUR CONTROL BOARD! I learned this the expensive way and had to replace my control board.
 
Thread starter Other Threads of Interest Forum Replies Date
J Under Construction 14
aquiapools Everything Else 0
B Everything Else 4

Other Threads of Interest