We do not recommend any longer than 100' under any circumstance (coupler or one-piece). You may run into trouble using a coupler since they can introduce noise and generate electrical "reflections" that can confuse the Coal-trol. This is especially true if you're going to have a long run. We find and recommend that non-spliced, one-piece cables be used to provide the most reliability and trouble free connection of your Coal-trol thermostat to the control module.
We can and do provide longer cables of various fixed lengths and also custom cable lengths, but you can use standard through type ethernet cat-5 patch cables as well. Generally you can find them cheaper than by buying from us directly.
If you have any more questions let us know either here, by email (firstname.lastname@example.org
) or by phone at 315-299-3589.