In fairness to all, we don't discuss pricing on the Wall. Thanks for your cooperation.
I need the benefit of experience. Here's the problem:
1. Installed iron rads in two different zones with common return line. Found that return flow from one zone was back-flowing through rads in neighbouring zone, delivering heat there even when thermostat called for none.
2. Installed swing check valve in floor frame where rad pipes travel, found the check valves sometimes made noise. Also reconsidered the wisdom of installing check valve in floor frame that would be sealed under new hardwood floor later on.
3. Removed swing check valves and installed spring check valve in pipe leading down from rad into the floor. Idea being ease of future replacement and quiet operation.
4. Check valves only installed in two of the four rads in the affected system, now all water flows to the two rads with no spring check valves, unless those rads are shut off manually. And even when these valves are shut, flow through rads with spring checks doesn't always happen. It seems the springs are too strong. There's definitely no air in the lines to block flow.
Is there any value in me pulling the rads off again, removing the springs from the check valves, then buttoning everything up again? The spring checks are in a vertical position, so gravity and any attempt at back flow should close the valves when they need to be closed.
Am I on the right track? Will the check valves make rattling noises without their springs?
In hindsight, I should never have installed a common return line for two zones, but I can't change that now.
Thanks a million!