02-05-2024 07:55 AM
Hello,
I have r/w/c heat only system running to a new addition. I have a taco sr503 control board. The nest was not detecting the cwire (connected to com on the taco board) so I purchased a power connector. Neither are able to pick up power with the nest. Additionally I tried running the c wire and power connector to the 24v slot on the taco board and this did not work. This works for my Nest learning (through power connector/older thermostat wiring).
I have 3 zones.
any ideas?
Answered! Go to the Recommended Answer.
02-06-2024 01:10 AM - edited 02-06-2024 01:24 PM
@Grepes ,:When using a TACO relay pack, including the SR-503 you need to install a 1000 Ohm, 1/2 Watt resister between the 24VAC Common and the W terminal of the thermostat connection. This is necessary for the Nest to be able to reach the 24 VAC common of the TACO SR-503. Your other choice is to use an available wire conductor attached to the Nest C terminal and the TACO SR-503 24VAC Common block in the upper left corner.
AC Cooling Wizard
02-06-2024 01:10 AM - edited 02-06-2024 01:24 PM
@Grepes ,:When using a TACO relay pack, including the SR-503 you need to install a 1000 Ohm, 1/2 Watt resister between the 24VAC Common and the W terminal of the thermostat connection. This is necessary for the Nest to be able to reach the 24 VAC common of the TACO SR-503. Your other choice is to use an available wire conductor attached to the Nest C terminal and the TACO SR-503 24VAC Common block in the upper left corner.
AC Cooling Wizard
02-07-2024 07:07 PM
Thank you, attaching the wire connector didn’t seem to work. How would I get the resistor all the way across the panel?
02-08-2024 07:46 PM
@Grepes , the resister does not have to go all the way across the panel. You can get a 1/2watt 1000 Ohm resister and insert one en in the Common terminal, then if the W is to far away, use a short wire and attach it to the W and the other end to the resister.
AC Cooling Wizard
02-14-2024 06:21 AM
Thank you @CoolingWizard. There is a COM and a 24v which should the 1k Ohm Resister be connected too? Additionally is this with or without the Nest power connector?