Is Stainless steel Ball needed for HVAC valves?

[EnergyProfessional]

I'm selecting some valves for HVAC. For flanged valves the better ones have SS-Balls. But for the smaller ones (1/2" up to 2.5" copper pipe) I like to use bronze valves and most have chrome-plated brass balls. Only few have SS-balls. The valves only will be operated occasionally (isolation valves), maybe once a year or for a repair. The water is kind of clean (HVAC system). Would an SS-Ball even be beneficial?

My understanding is SS-Balls wear less if the valve is operated often. But I also wonder if corrosion is a problem?

My main concern is that a valve doesn't get operated, it will corrode stuck. OR am I paranoid and Brass-balls will be fine for me? Fluid velocity typically is not more then 4 fps, often less (variable volume).

I also use isolation valves for pressure sensors. Those would not get any flow. I assume an SS-Ball would be overkill for those? I also use Valves as bypass during system flushing, so they get flow only once or twice in their life.

I guess part of what I need to know what the exact reasons are to require SS-Balls (wear? corrosion?) to make a better selection. Typically I like to use the best material so we don't have repairs, but it seems having SS-balls in every application may be overkill?

 

[katmar]

My experience, particularly in the smaller sizes, is that SS valves are no more expensive and can even be cheaper, simply because they have become the standard and are produced in such large quantities. If there is no economic advantage in using the lower spec valves then the choice becomes easy. Regarding possible corrosion see thread338-270642

Katmar Software - AioFlo Pipe Hydraulics

http://katmarsoftware.com

"An undefined problem has an infinite number of solutions"

 

[tbuelna]

A ball made from through hardened 440C would be just as corrosion resistant and far more durable than a chrome plated brass ball. It also would not cost much more.

 

[EnergyProfessional]

Katmar: maybe I need to do some more cross-shopping. but prices for 1/2" valves ranged from $6 for brass body-brass-ball to $ 26 for bronze-body-SS-ball valves.
It also seemed when you see Watts and Nibco etc. websites the majority of valves have brass body, and brass balls. Fewer have bronze bodies, and even fewer have SS-balls.

For 2" Valves with SS-ball the dealer even gave me a December availability (you notice it is August now). So SS-balls are less available and tend to be more expensive.

If price was the same, it wouldn't be a question which to chose. but for a Pressure gauge and pressure sensor setup around one boiler i need 4 valves (1/4"or 1/2" doesn't matter) and the cost seemed excessive for vales that never see flow. But maybe I'm better off to just pay more for peace of mind. If you add all labor etc. those few $ more are just a fraction of a %.

Any advice on Brass vs. Bronze body? It seems Dezinkification isn't really an issue in closed loop HVAC systems?