Red & white wires swapped

Old 11-08-16, 07:25 AM
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Red & white wires swapped

I had a Taco SR503-4 installed along with a new aquastat on my oil-fired hydronic system. Being the AR person I am, I had to look at the wiring. It all looked fine, except that Zone 3, connected to a Honeywell RTH7600D, had the R & W reversed. I double-checked that the colors were correct at the thermostat (I was certain anyway, as I had done that install), so I swapped the wires at the 503.

Just curious as to any potential side effects of having the wires in the incorrect spots. Thanks.
Old 11-08-16, 08:38 AM
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Colors do not mater on that 24V circuit. It's not like a 110V with a hot and a common. Either way would work fine. I'm only talking about a 2 wire 24V circuit, not a 4 or 5 wire where you have a fan or compressor terminals on the t-stat. Those must be installed correctly.
Old 11-08-16, 05:56 PM
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If this reassures you: I have a spool of 2-conductor thermostat cable, and both wires have the same color (white). I have used it all over my heating system with 24-V controls.
Old 11-09-16, 07:48 AM
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any potential side effects of having the wires in the incorrect spots.
The test is not whether “it works” but can it cause problems in the future?

Sticking with common, widely accepted practices makes things easier for someone in the future to work on or trouble shoot the system.

Systems should be wired so in the future experienced technicians can easily trouble shoot it.

I have wiring diagrams and manuals by the boiler to help a stranger deal with it.

Last edited by doughess; 11-09-16 at 09:32 AM.

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