Hi all,
So I'm currently planning the install of my Nest 3rd Gen but there's 1 part which has me confused/stumped.
The hot water cylinder thermostat (Honeywell L641A) has 3 terminals; C, 1, and 2. According to their instructions https://heatingcontrols.honeywellhome.com/Documents/Installation-Guide/pdf/1152.pdf the heating load connects via terminal 1. Now it does say "Terminal 2 used on Y-Plan systems" but as i understand it that's used to turn the HW off so no heating load.
My HW thermostat is currently wired as followed;
Terminal C to the Programmer
Terminal 1 to Boiler, Pump and Orange on the 3 way valve
Terminal 2 to Grey on the 3 way valve
However....
The Nest Y-plan instructions show the heating load comes out of terminal 2
Any clarification would be greatly appreciated, thank you.
So I'm currently planning the install of my Nest 3rd Gen but there's 1 part which has me confused/stumped.
The hot water cylinder thermostat (Honeywell L641A) has 3 terminals; C, 1, and 2. According to their instructions https://heatingcontrols.honeywellhome.com/Documents/Installation-Guide/pdf/1152.pdf the heating load connects via terminal 1. Now it does say "Terminal 2 used on Y-Plan systems" but as i understand it that's used to turn the HW off so no heating load.
My HW thermostat is currently wired as followed;
Terminal C to the Programmer
Terminal 1 to Boiler, Pump and Orange on the 3 way valve
Terminal 2 to Grey on the 3 way valve
However....
The Nest Y-plan instructions show the heating load comes out of terminal 2
Any clarification would be greatly appreciated, thank you.