MasterTemp and Intellicenter

spal24

Member
Mar 13, 2022
8
Bethel Park, Pennsylvania
Pool Size
18500
Surface
Fiberglass
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
We had our pool installed in the spring and the pool installers electrician made all the connections. Currently we can not monitor the Mastertemp heater because they did make a connection to the rs485 on the heater. Instead it is a 2 wire connection to the fireman's switch that turns it off and on. He is telling me this is how Pentair has told them to connect it. Way it is currently wired I can not change the temp on the heater from the intellicenter. It simply turns on and calls for heat but if the intellicenter reads lower than the heater it shows it is heating but it is really not.

My question is can I simply add the rs485 connection or do I need to remove the 2 wire connection to the fireman's switch when I add the rs-485?

Thanks for any help in advance.
 

rstrouse

Well-known member
Jun 17, 2020
485
California
The heater may only be configured as 2 wire or RS485 control. It will not do both at the same time and it will not fix your woes with the temperature differential. In IntelliCenter, it the water temp probe is off you can calibrate it to match the temperature recorded by the heater. But MasterTemp cannot be adjusted and the temperature readings are not shared between MasterTemp and IntelliCenter. So it is possible that the temperature readings between the equipment can be off but you can calibrate IntelliCenter to the heater.
 
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spal24

Member
Mar 13, 2022
8
Bethel Park, Pennsylvania
Pool Size
18500
Surface
Fiberglass
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
The heater may only be configured as 2 wire or RS485 control. It will not do both at the same time and it will not fix your woes with the temperature differential. In IntelliCenter, it the water temp probe is off you can calibrate it to match the temperature recorded by the heater. But MasterTemp cannot be adjusted and the temperature readings are not shared between MasterTemp and IntelliCenter. So it is possible that the temperature readings between the equipment can be off but you can calibrate IntelliCenter to the heater.
So if I switch it to rs-485. The temperature comes from the IntelliCenter temp sensor and I can increase temperate there. The heater basically is under the control of the IntelliCenter correct?
 

rstrouse

Well-known member
Jun 17, 2020
485
California
Unfortunately when using RS485 it only changes the setpoints and those setpoints are matched to the heater temperature probe. So if the heater probe isn’t accurate then it won’t match your displayed pool temp. 2 wire will use the temp probe assigned to IntelliCenter.

However if you think any heater is going to hold a constant temperature to a single degree you are mistaken. The heater will heat up to +2 degrees and -2 degrees to restart. Otherwise it would short cycle constantly when it reaches the temp. This does not matter which interface you use.
 

spal24

Member
Mar 13, 2022
8
Bethel Park, Pennsylvania
Pool Size
18500
Surface
Fiberglass
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
Unfortunately when using RS485 it only changes the setpoints and those setpoints are matched to the heater temperature probe. So if the heater probe isn’t accurate then it won’t match your displayed pool temp. 2 wire will use the temp probe assigned to IntelliCenter.

However if you think any heater is going to hold a constant temperature to a single degree you are mistaken. The heater will heat up to +2 degrees and -2 degrees to restart. Otherwise it would short cycle constantly when it reaches the temp. This does not matter which interface you use.
I think the rs485 is the way to go. I just want to be able to change the set points. In the two wire I can not adjust the set point.

Sorry for talking in circles. Thanks for your help.
 

Turbo1Ton

Gold Supporter
Dec 26, 2019
1,341
NE Oklahoma
Pool Size
14500
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
In the 2 wire you can certainly change the set point the only real thing you gain from RS485 is returned errors from the heater. MasterTemp operation through either interface is indiscernible.
When using the 2 wire fireman's switch, the set point adjustment only changes the Intellicenter set point, it has no effect on the actual set point of the heater. Meaning if for some reason the heater setpoint changes from 104, then you have to manually adjust it back at the heater. This has happened to me previously, not sure why, power outage maybe?

When using the RS485 comms, adjusting the set point adjusts the IC and the heater set points simultaneously. No more needing to verify the heater set point has not been altered and is above the IC set point.

The temperature differential issues between the heater and the IC temperature sensor could still be an issue, as rstrouse mentioned.

To answer the original question, if connecting the RS485, the fireman's switch connection is not needed. If the heater is connected via both the RS485 and the fireman's switch, it will prioritize the RS485 connection. When I first converted mine to the new board with comms, I left them both connected for a short time, not knowing that I didn't need the fireman's switch connection.

--Jeff
 

spal24

Member
Mar 13, 2022
8
Bethel Park, Pennsylvania
Pool Size
18500
Surface
Fiberglass
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
Thank you both for responding. I am going to look into switching to rs-485 connection in next day or so. Again thank you both for the input. This forum is really a great place.
 

sdpugsley

New member
May 28, 2021
1
Ontario
My installer just stated that you set the MasterTemp temperature to 99 degrees or similar, and let IntelliConnect use its own probe to turn the heater on and off. Basically, set the heater to 'always on', and let the remote controller turn it on and off as necessary
 

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