Click here to Find a Contractor in your area.
Welcome! Here are the website rules, as well as some tips for using this forum.

If you've found help here, check back in to let us know how everything worked out.
It's a great way to thank those who helped you.
Need to contact us? Visit

Boiler cycling easy fix

My system is a six zone system with zone valves and a ModCon boiler. I access the run time and cycles. The boiler was cycling 40x an hour during the winter months. I have a Taco ZVC control.
I disconnected the end switch from the control going to the boiler so the zones will not call the boiler. I took the largest zone hooked it up to a separate ZVC controll with that end switch calling the boiler and boiler pump and the system pump. I adjusted the outside temp curve to a lower at point temp so it would run longer to satisfy the house temperature.
The boiler only calls for the main zone. The other zones will call and wait till the main zone call for heat.
The boiler only cycles 4-6 times an hour. My therms for last year dropped by 20%.
The final test is that my wife hasn't complained about the heat.

Rich S


Sign In or Register to comment.


It looks like you're new here. If you want to get involved, click one of these buttons!