Best valve for balancing, gate or globe

Solid_Fuel_Man

I've read that a globe valve is best for throttling flow long term. Although balancing valves are pretty much always ball valves, or some type of modified ball. 

What say the wisdom of the Wall? 

Jamie Hall

Never use a gate valve for balancing. They're built for and intended to be either fully on or fully off.

As to ball vs. globe... well, globe gives you better control, but at the cost of much higher head loss even fully open. There are, also, specialty valves (pricey!) for really good -- and linear -- flow control, but in my humble opinion they are overkill for this type of application. If it were mine I'd use a plain vanilla ball valve...

hot_rod

The valve with the smoothest flow passage, best adjustability, price, etc?

As for static, manual balance valves.
Basically there are 3 types of commonly used balance valves.
Ball type are very common, all the hydronic manufacturers offer ball style, usually the best price point. The B&G circuit setter is probably one of the most commonly speced valves.

There are are pros and cons to all 3 types. Generally you do not want to choke down a ball valve much beyond 45- 50% as it presents two sharp edges of the ball to the flow stream. Noise and wear could be result of cranking way down. A tiny movement of the handle at the end of the range make a big jump in flow. really do not want to oversize this type of valve. Don't install 2" and try to balance down to 1 gpm

Fixed and variable office are the next two. The wheeled handle and fine thread allows for very precise adjusting. You need a ∆P gauge to dial them in and a chart with some to relate ∆P to gpm. Notice where the pressure ports are on the valve to determine which type of valve you are looking at. You read the pressure drop across the orifice, to make the adjustments.

It really comes down to designer preference, some engineers prefer fixed, some variable office, Ford or Chevy. There are many variations of these 3 common types of balance valves. Features and construction vary from brand to brand.

More and more we supply dynamic balance valves, you select the required gpm and the valve modulates and self adjusts. To a point.
Then there are thermal balance valves, also dynamic, which use a term actuator.\

Pretty deep subject, calculating and selecting balance valves, lots of math involved. It took a lot of pages in Idronics 8, to just scratch the surface of flow balance.

https://www.caleffi.com/sites/default/files/coll_attach_file/idronics_8_0.pdf

JohnNY

Plug valve.

MrCofDG

More of a question - I just discovered(!) I have two THRIFT brand balancing valves, each leading into a 3/4" copper tube baseboard; they have a screw head top on them, which I assume works as follows: if the screw head slot is aligned with the pipe then it's 'open'; if the screw head slot is turned perpendicular to the pipe, then it's 'closed'. Anyone know the internal mechanism of these things?
P.S. i don't think these things are sold anymore....

hot_rod

Thrush maybe? Yes, I would think if it is a 1/4 turn type valve, you are correct.