Check valve help please

[cumminstinkerer]

I have an econoburn 100 with the bypass circ setup as econoburn says for return protection, the issue I am having is the check valves from the box stores all take around 2 PSI above static pressure to open, I believe that most of our circs can't really generate that kind of pressure, the valve i currently have will chatter and it seems like the system is really slow to move the heat to storage, although the boiler does not over heat. Any thoughts would be great, Thanks guys.

 

[maple1]

I have never had any issues with my checks working OK. They are the cheap simple swing checks. Don't recall hearing chatter either. Not sure what the number is, but I think between the suction pressure on one side of the check & the push pressure on the other side of it (so to speak, I kind of butchered that description), there should be more than 2psi dP on the check flapper thingie? Someone who has measured pressures on each side of their circ can likely answer that better than me.

 

[cumminstinkerer]

Thanks @maple1 I can hear it chatter, the one issue i wonder about making a difference is I am open system with exspanion/vent tanks above the boiler about 2.5 ft and the check is on the return side at the base of the boiler, just a thought but could that be causing to too much pressure on the close side, my check is a EZ-Flo 20405LF I believe

 

[Bad LP]

Mine was giving me trouble so we took out the swing and quickly learned it wasn't needed.

 

[cumminstinkerer]

@Bad LP that is what I am going to try tonight, its a bit of pain but I think I can make it pretty simple

 

[Bad LP]

@Bad LP that is what I am going to try tonight, its a bit of pain but I think I can make it pretty simple

Mine is visible but it took a little work cooperating. Sort of like a tooth with deep roots.

 

[E Yoder]

I'm assuming the chattering check valve is a spring check. If you look at them, some have two "guides" inside for the shaft, others have one guide.
I've seen the single ones wobble at certain flow rates, creating the chatter.
A regular circulator can produce 2 psi no problem, it will slow the flow rate down a bit of course.

 

[cumminstinkerer]

Update,
Remove the check vale and all seems much better, I do not get any flow in the direction I was trying to check so I am good I think. @E Yoder this was a single spring, maybe that had to do with the chatter. this style check is definitely a pretty good restriction, I think if I were to need one I would go with one for at least double the line size you are trying to check. I would really like someone to chime in on how much flow restriction a spring style check really does create, I bet it is more than we think, just from my results.

 

[RockyMtnGriz]

Stupid fact, but FWIW, if you dig deep into the specs for check valves, they will have a minimum flow that is required so that the valve fully opens and is pinned against the stop. At lower flows, the valve is constantly moving with the turbulence of the water and wears out much more quickly. It's very relevant in applications like a city water system, but otherwise how much does this matter? Well I don't worry too much about it. For instance, the spring check on my 1" domestic water inlet is probably almost always below the minimum flow, but I'm not changing it for a smaller one for the rare occasion I need max flow. Same goes for the stuff on my circ pump loops. I don't want the restriction or plumbing headaches of a smaller "proper size" valve. 3/4 check valves are cheap, and won't wear THAT fast, if they even wear out before I do.

I throw this out in case it might help someone who has a real wear problem. The answer, according to the valve manufacturers, would probably be a smaller valve, in which case I'd be sure to opt for a low restriction style (swing?).

Yes, spring type check valves will create a lot of restriction when the pressure available to overcome them is small. There are spec sheets that will detail all of that if you're willing to root around a manufacturer's website.

 

[E Yoder]

I don't think the swing type checks are supposed to be used in a circulating system? I forget why, the slap of the water can break them or something like that. ? Seems like I read that somewhere. I've always used the spring checks if needed.