Mastertemp communication error.

[dhulfiqar8409]

Hi there i was able to set thing up on raspberry pi 5 , configure everything pretty much, and everything is working fine even the heater itself, just keep seeing this error, Im using Rs485 to the heater and the pump,. I can set the heat temp normally and its working just this error along with no successful Received from the pool. One note , the heater wasn't working when i had the GRN connected to the rs485 adapter GND, the moment i disconnect it , the heater works again but still with this error.

[tagyoureit]

Hi, the most likely cause here is that data is being sent to the pool heater correctly, but we are not receiving any communications back.

Per the MasterTemp manual pages 37-39, you should see “RS485 Control” on the heater panel.

From the njsPC side, you can use MessageManager to view the packets. Filter down to only heater messages and you should see something like the following:

Source OCP to Dest Heater[1] (Action 114) is the outbound communications. You will likely see this one. Source Heater[1] to OCP (Action 115) is the reply. You will probably not see this one.

Check your wiring carefully. Make sure DT+/DT- are connected. These are the YEL/GRN wires in the picture. BLK/GND is just your standard ground and not part of the communications path. If you have the yellow/green connected to screw terminal ports 2 & 3 and you still only get one way communication it may indicate a break in the wiring. In that case, try another physical wire between the OCP and Heater.