chilled water valve location

[skorepeo]

if i have a chilled water valve and a circuit setter. what is the correct location? before the coil? after the coil? and why?

I am saying that the circuit setter goes before the coil in the supply side and the chilled water valve goes in the return after the coil. If I am correct why? and if I am wrong why?

[flange]

when using a circuit setter, it is a calibrated orifice. That means that it is used to measure and set flow, but it also means you create a pressure drop across it and an increase in velocity just after the device. It is better for this to occur in the return piping than in the coil. After a short distance velocity settles out, but if its right at the coil, you could have turbulence and affect performance. typical it would be used as a dual use valve, flow control and isolation.

As far as the control valve, is it two or three way? two way typically goes before the coil, three way can be either.

[desert guy]

I can't answer the question about the circuit setter but every valve I have seen either CHW or HW, was in the return regardless of whether it was a two way or a three way with the exception of three installations.
I came into the trade in 1981 starting out as an electrician for a controls company and have seen a few installations. :)

[flange]

in my honeywell grey book, they tell you to put the two way valve in the supply, but no explanation of why. i dont think it really matters that much, EXCEPT in heating applications. three way valves are ambidextrous, but piping of same matters.

[just_opinion]

if i have a chilled water valve and a circuit setter. what is the correct location? before the coil? after the coil? and why?

I am saying that the circuit setter goes before the coil in the supply side and the chilled water valve goes in the return after the coil. If I am correct why? and if I am wrong why?

2 way-valve -Downstream of the coil
3 way-valve - It depends if it is diverter or mixing
Diverter - Supplying/inlet pipe of the coil
Mixing - Returning/outlet pipe of the coil

Circuit setter - Either ends
On the Return then gives it at lease 1-diameter STRAIGHT distance
On the supply end then gives it at least 3-diameter STRAIGHT distance

[GA FRANK]

Contol valve and balancing valve on return side prevents air from building up
in cooling coils.

[ascj]

Contol valve and balancing valve on return side prevents air from building up
in cooling coils.

Could you elaborate? I'm not seeing why.

I always see 2 ways on supplies. 3 ways are mostly on returns. Circuit setters always on returns.

Aren't mixing valves more common and cheaper?

[GT Jets]

Contol valve and balancing valve on return side prevents air from building up
in cooling coils.


This is "almost" correct. Putting the balance and or isolation valves in the return side makes it easier to purge the air from the coil.

Air will not actually "build up" but it may get stuck due to the inability to have the coil under a higher pressure than the return line....

You have to also take the pressure differential rating of the valve in to account...Some valves require a larger actuator if put before the coil because you cannot factor in the pressure drop of the coil. This is only when the system is engineered to the gnats ass and not over sized like we normally see (meaning slop counting the same as skill)...

GT

[GA FRANK]

There are always air bubbles in a chilled water loop ,no matter how well
designed.If pressure is kept constant on the coil the air is more likley to be
removed from high point air vent.Air removal euipment is on suction side of
pump.

[GT Jets]

There are always air bubbles in a chilled water loop ,no matter how well
designed.If pressure is kept constant on the coil the air is more likley to be
removed from high point air vent.Air removal euipment is on suction side of
pump.

Not "always" though....:anyone:

Sometimes air bleeds are simply installed on the high side of the system on both the supply and return lines.

The reason you see "permanent" air vents an the suction side is because of the typical piping practices used...In other words, the outlets are on the top of the coils in most cases.

GT

[GA FRANK]

I was refering to air removal equipement such as B&G rolairtrol not just high
point air vents. Hope it is o.k. to mention brand.

[manny238]

what kinda valve you installing 2 way or 3 way?

[leoxxl]

2 way-valve -Downstream of the coil3 way-valve - It depends if it is diverter or mixing
Diverter - Supplying/inlet pipe of the coil
Mixing - Returning/outlet pipe of the coil

Circuit setter - Either ends
On the Return then gives it at lease 1-diameter STRAIGHT distance
On the supply end then gives it at least 3-diameter STRAIGHT distance

Downstream of the coil is normally the supply line, right?

[GT Jets]

Downstream of the coil is normally the supply line, right?

No, Leaving....I am not convinced it matters from a performance standpoint (on the two way deal), it allows you to use a lighter duty actuator if on the leaving side though..

GT

[emcontrols]

In my experience the control valves weather CHW/HW 2-way or 3-way is to be on the outlet (return line) always keeping the coils flooded. It also performs better heat transfer and tighter control. The only application in my experience, that you put the control valve on the inlet (supply) would be on a steam coil. Reason is you do not want the condensate to trap in the coil.

As a tech if I see the valve on the inlet I recomend changing it to the outlet.

Ditto on the balancing valve/circuit setter.

[slugger1]

i have seen some crazy piping. but as far as i'm concerned control valves 2 or 3 way go on outles of coil, and pipe in accordingly in the bottom out the top, ecsept as said above in case of steam heat in the top out the bottom of coil. circuit setter what ever type grisswold etc go on outles of coil, dif pres causes proper gpm flow through coil if sized right.