Control Valves for Terminal Equipment
Control Valves for Terminal Equipment
(OP)
Does anyone have a recommendation of whether to place control valves upstream or downstream for terminal heat transfer equipment (I.e. VAV boxes, fin tubes, convectors, unit ventilators, etc.)?
I am speaking of hot and/or chilled water coil scenarios.
I have been told for VAVs that downstream is better to avoid water hammer.
Any help would be greatly appreciated.
Thank you
I am speaking of hot and/or chilled water coil scenarios.
I have been told for VAVs that downstream is better to avoid water hammer.
Any help would be greatly appreciated.
Thank you





RE: Control Valves for Terminal Equipment
Not 100% sure of the reasons, but I think they could be these:
1)Keeps the coil filled all the time (which avoids air pockets, avoids having to refill the coil, helps keep thermal momentum after closing the valve, etc...)
2)Makes for more stable control
I think there are other reasons I am not thinking of at the moment, but certainly downstream of the coil.
HOWEVER, on occasion, when a 3 way valve is used, particularly at a boiler, it may be in a diverting ionstead of a mixing scenario which will actually be more upstream of the boiler. This is not seen very often, just wanted to throw it out there.
Ed
RE: Control Valves for Terminal Equipment
RE: Control Valves for Terminal Equipment
http://www.eng-tips.com/viewthread.cfm?qid=25360
RE: Control Valves for Terminal Equipment
One additional question for HVACctrl,
Your reply mentioned, "Makes for more stable control". Could you elaborate on this? Not really sure why?
Thanks