Hi, I'm replacing an old AT88A with the AT175F for my hydronic heating, which is connected to my 2-wire mercury t-stats and Honeywell V8043F zone valve motors (yellow leads). Wiring diagrams always show the "hot" red wire from the transformer going first to the t-stat, then white wire from t-stat to zone valve, then from zone valve back to "common" on the transformer. The two secondary wires on this transformer are Blue and Yellow, and the "common" on the Primary side is Black. The footnotes on the instructions say: "Black is common with respect to the transformer winding only and not the external circuit".
I need some clarification on how this should be wired:
(1) On the Primary side, the Black lead should be connected to Line White (Neutral) and the Red lead should be connected to the Line Hot (Black) (120V). Is this correct, or does it matter?
(2) On the Secondary side, which of the Blue/Yellow leads should I consider as the "red/hot" wire shown in the diagrams for wiring up to t-stat? And, does it even matter?
(3) If if doesn't matter in #2 above, and I want to use this setup with a smart t-stat that requires a third C-wire, does it THEN matter which is connected to R/Rh on the t-stat?
You can find the link to the AT175F manual here.
Any advice would be appreciated.
Thank you.
I need some clarification on how this should be wired:
(1) On the Primary side, the Black lead should be connected to Line White (Neutral) and the Red lead should be connected to the Line Hot (Black) (120V). Is this correct, or does it matter?
(2) On the Secondary side, which of the Blue/Yellow leads should I consider as the "red/hot" wire shown in the diagrams for wiring up to t-stat? And, does it even matter?
(3) If if doesn't matter in #2 above, and I want to use this setup with a smart t-stat that requires a third C-wire, does it THEN matter which is connected to R/Rh on the t-stat?
You can find the link to the AT175F manual here.
Any advice would be appreciated.
Thank you.