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applying 24v to Tekmar 274
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trl14
Member Posts: 5
I'm twining 2 utica UB-95s together.I'm using a Tekmar 274 to control the boilers and provide outdoor reset.Tekmar wants 20v min. to the "boiler demand" terminals. I have 2 t-stats going to a control box that looks home made and 1 going to a honewell r87 single pump control the 2 tt's are conncted to the 274 but I do not have 24v there just dry contacts. how can i tie a 24v transformer to my "endswitchs going to the tekmar control?
Thanks
Thanks
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tekmar 274 boiler demand wiring
To provide a 24V powered demand to the tekmar 274 do the following: Run two wires from your end switch (let's call it X1-X2) to the 274 enclosure. Connect one of these wires, let's say X2, to the 274 boiler demand terminal 22.
Now run two wires from your 24V transformer R & C to the 274 enclosure. Connect the C wire to the 274 boiler demand terminal 21. Connect the R wire to your end switch X1 wire with a wire nut.
Now power the system and transformer up. You had it turned off right?:)
Now whenever the end switch closes the 274 boiler demand will be energized and the control will start targeting based on Outdoor Air temperature. The Application drawing A274-5 shows something similar.
The boiler T-T connections are wired to the tekmar boiler dry contacts. This should fire the boiler(s) when it closes. I hope this helps and have a Merry Christmas!0
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