Mastertemp with RS485 not working with IC

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Nateski

Nateski

Active member
Jun 2, 2023
43
Arizona
Hooking up my Mastertemp 400 to Intellicenter on brand new build. Wired MT400 via RS485 to IC. IC is NOT controlling the MT400 correctly. I understand that when it's working correctly, the manual heater controls should be disabled (and heater display should say so) but they are not. IC does show correct temp of water and sometimes it will call the heater to come on, but I can't set the temps and heater on/off with the IC and have it actually work as desired. It feels like I may have missed a step to get things to handshake. When I configured the heater in IC, I did not see any choice for the Mastertemp specifically, just a generic gas heater. Is there something(s) I need to do on the heater manually to prepare it to be correctly seen by the IC?
 
Okay, after several deletions of heaters and adding new ones, I finally got the choice of Mastertemp to show up in the 'type' field and 'Connected Gas' finally appeared. Hopefully, this will get me online fully. Thanks again.
 
Nateski said:
Okay, after several deletions of heaters and adding new ones, I finally got the choice of Mastertemp to show up in the 'type' field and 'Connected Gas' finally appeared. Hopefully, this will get me online fully. Thanks again.
Click to expand...
That's what you needed.
 
I'm stumped. I've got the Mastertemp installed with 'Connected Gas' showing. I have the set temp for both the pool and the spa on the IC really low (like 40 degrees) so the heater doesn't come on during a normal pump cycle. Both the Pool and Spa show Mastertemp as the heat source in the IC. The heater itself does not seem to reflect that the IC is in control... I don't see any notification on menu on the heater that it is being controlled by the RS485 (I thought I read somewhere that it was supposed to reflect that). So, my heater comes on whenever I run the pump for either the spa or the pool. Is there a final step that takes the heater out of the control and leaves it to the IC?
 
Check that the RS-485 wires are connected properly at the heater and IntelliCenter. See pages 37-38 of the MasterTemp Installation Manual.

When a heater is being controlled via the RS-485 interface:
  • The heater front panel buttons are inactive. Press a panel button to turn on the LCD display. “RS485 Control” is displayed.
  • Heater Alarms/Errors are displayed on IntelliCenter’s control panel(s) Status Home screen.
 
Okay, all wiring is okay (RS485 on heater circuit board and Com Port J5 on IC, Black, Green, Yellow as called for). Also, there IS indeed a jumper to set on the MT circuit board to enable or disable the RS485. So, set that for 3-wire. Now, heater display says "3 Wire Control". But display also now says "Heater Off" and no amount of keying on the heater will change that. Heater display shows both Pool and Spa at "MAX". However, now heater won't come on when the IC set temp is increased to call for heat. Any ideas?
 

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UPDATE: Sometimes I wonder if Pentair hires documentation writers with the specific goal of making these configurations more confusing. Page 40 of the Heater manual shows a jumper to be set to 'enable 3 wire control'... which you would think is all about the RS485 3-wire connection (what else could it be?). That is why I enabled it (post above). In trying all kind of things to solve my continued problem, I switched the jumper back to 'disable 3-wire control' and now... voila... the heater displays "RS485 control" on the display and now it's working as expected. Go figure.

Hope this post helps someone else with this issue.
 
Glad you figured it out. Pentair manuals have never been written for the common man. Neither has Jandy or Hayward manuals.

Enable 3 wire control is for when you are using n external2-way switch connected to the POOL-COM-SPA spade lugs on the PCB.
 
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