1 zone too hot on 4 month old slant fin boiler.Seperate circulators(supply side) for 3 zones, none of them on at the time. Tapped flo check valve with a hammer and baseboard cooled down. 2 days later same problem, same fix. Hopefully it is not wrong, but flo checks are on the return side. Taco 220 is the brand. Can these be cleaned or adjusted or will the sticking one need to be replaced? Thanks for the help

 

Here's a link to the PDF file for replacement parts for the Taco FlowChek valves.

http://www.taco-hvac.com/uploads/FileLibrary/ReplacementpartsFloCheck101-004.pdf

You might have to go to a heating supply house or large plumbing house to find the parts. The entire valve is under 50 bucks, so it might be most practical to replace the entire assembly. The entire mechanism unscrews from the top for service or replacement. Hopefully it's just some crud getting stuck under the weighted flapper keeping it from closing fully.
Seeing as your system is so new, I'd bet on something being stuck in the valve--loose piece of teflon tape, etc.

The problem is whether you have close in cutoff valves for servicing, if you have to drain the entire system to service it you might consider waiting until spring or having a pro do it.

Pete

 

It's ok on the return, but make sure it's facing the right way.