Noisy Taco flocheck

I recently switched from oil boiler to an efm 520. I used the existing flow check valves. When my upstairs zone is calling for heat my Taco 220 on that zone is rattling. Do you think this is air or low flow causing this? I am using the same circulators from the oil furnace. They are mounted in the back on the return line. The flow checks are mounted on the outlet right off the top of the boiler.

If there is any steam in the pipe it will cause that rattling. Check temps.

What do you mean by check temps? The boiler temp fluctuates between 140-160. The pressure is 22-26.
Thanks

Any thoughts?
Thank you

If the circulator for one particular zone is oversized, it can cause flow in other zones...and rattle the flowcheck in the process. If there is a valve on the discharge side of the circulator, try closing it halfway.

Thanks for the response. The valve that is rattling is the one on the zone calling for heat. If there is a valve should I still try closing that a little?

If the check is on the same zone that is running, it is probably just worn. You can try changing the harmonics by adjusting that valve.

Rob R. wrote:If the check is on the same zone that is running, it is probably just worn. You can try changing the harmonics by adjusting that valve.

Hi Rob R., not trying to steal this thread but, this is the first time I've read about check valve rattle on this site. I have check valves in each one of my secondary circulators. They've rattled from day one (new). Only the zone calling for heat would rattle. It does not rattle other zones. From what you're saying, the check valve has too much freedom, which is why it rattles. Closing the ball valve a little would put more constant / steady preasure on the check valve, elimitating the rattle. Am I thinking correctly? I answered my own question: I just walked down cellar and tried closing the ball valves some. At about 45* closed, the rattle quieted down, but is still there. I also noticed a new noise of the circulator working harder. So, I openned the ball valves again. The only room I hear rattle is the office, just above the circulators. Before putting check valves in the circulators, the entire system was whisper quiet. Oliver

The check valves in your circulators are just a piece of plastic with a small spring...I have never heard one of them rattle. The Taco flow-check mentioned earlier in the thread is the old weighted style, which basically has a weighed metal disk that slides up and down on a rod.

Rob R. wrote:The check valves in your circulators are just a piece of plastic with a small spring...I have never heard one of them rattle. The Taco flow-check mentioned earlier in the thread is the old weighted style, which basically has a weighed metal disk that slides up and down on a rod.

Yes, I knew this post was talking about a independent in line check valve. It's the rattling noise, and remedy that caught my attention. Your remedy sounded logical, and something that never entered my mind. So I gave it a try. And yes, it does make quite a difference in rattle noise. If it wasn't for ghost flow, I'd pull the check valves back out of my circulators. You've never heard rattle in circulator check valves? Any ideas? This is my first hydronic system. It performs very well. I do see little changes I'd make on my next system, where I could do away with check valves, and ghost flow. I actually wanted to design a drop loop into my present piping system, but HAVAC buddy was against it for some reason.

Guys,

Everything I ever read about hydronic heating says emphatically , the circulators should be on the supply side of the boiler. . Too, does each zone have its own check or is it on the manifold? Ideally the check should be at the outlet of the circulator, at least in my experience..... I hate gremlins youll get it keep after it.

Waldo

Air in the system can also cause flow checks to rattle. This situation can occur with the circulator on either side of the boiler...but it is somewhat easier to rid the system of air with the circulators on the supply side.

Another "old rule" is to have at least 12" of straight pipe before and after the circulator to reduce turbulence.

Do you by any chance have isolation /balancing valves on the return line of the reconfigured system? What position are they in? How about a balance loop [feed to return] in the boiler piping ? Could a valve that was used to purge or start the new system be left in "partial" position compared to when it was used on the oil system? It has got to be some flow characteristic that is present now and was not present when the oiler was being used since you say it is essentially the same hardware. I had the same trouble a bit ago and in my case it was because I had too much flow in my equalization line on the boiler itself. It turned me every way but loose for a while but I finally got it and you will too.That tink ,tink,tink, can drive a person nuts!!! Keep thinking flow and pressure differential across that flow check,and then figure out how to alter it. Mike

Thanks Mike.
I do not have any isolation valves. I put a new air release valve on that zone. It seemed to have helped some so maybe it was just air. I will try to do my best to make sure all the air is out and let you know how I make out.
Thanks to everyone for their help.

I had that check valve noise happening in my system and a good banging with a hammer straightened it all out for a while.