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Burnham Alpine 105 wiring for DHWP

Slowhand63 Member Posts: 80
Can someone confirm the proper wiring of the indirect HW tank for an Alpine 105 boiler? As per my other very lengthy thread - "Burnham Alpine 105 - DHWP - ?" (lots of pics of my system) I have a situation where the radiant heat seems to be priority although DHWP is enabled in the Sage 2 controller. I believe the issue is the way the system is wired. I traced the wiring from the Alliance HW tank this morning - 4 wires - 2 are spliced and run to the 24v transformer, the other two are connected to the second and third slots from the top (RED = "Heating T-stat/DHW temp switch" and WHT = "DHW Temp switch"). This looks correct to me. Can anyone confirm? What else would the boiler need to know that both the radiant and HW tank are calling for heat? Thanks in advance.


  • Slowhand63
    Slowhand63 Member Posts: 80
    I am posting some rough drawings of the wiring. While tracing the wiring I found a missing wire nut with two wires barely touching. The wires were for the 24v to the mixing valve. I did not notice if the mixing valve was working properly or even had power before I reconnected the two wires. Based on the symptoms I've described - does it seem logical that this was the issue? Put the radiant on this morning and it when calling for hot water they both seemed to be running simultaneously (as opposed to only the DHW indirect tank) but the DHW indirect tank supply and return were HOT which I took as a good sign.