Control Valve selection

Yoy need to know the maximum flow rate in liters per second or gallons per minute, the other fan coil units in the system to establish if you need tweo or three way and then go to a valve manufactureres (ie Honeywell, Johnson etc) catalogue. Good luck

You need to give other details like line size, Flow rate maximum, Line pressure

Regards

C.S. PANT

The rule of thumb is that the pressure drop across the control valve should be larger than the pressure drop through the coil (and strainer) to insure good modulating control. Because control valves only come in certain Cv sizes, you usually compromise by having a pressure drop a little less than the coil pressure drop figuring that as the valve throttles, the pressure drop will increase to where the valve will take control of the flow. Over size the valve and you get loose control. Under size the valve and you get insufficient cooling.

A good target for pressure drop across a full open control valve is 2 psi. With fan coils one often winds up with effectively 2 position control (especially with heating hot water) as the flows are small.

If the fan coil also has mixed air (outside air and return air), you would be better off with a unit ventilator with modulating face and bypass dampers around the cooling coil and no control valve, to reduce the tendency to get high humidity problems. Nothing worse than taking in outside air and cooling it down to just the dew point and delivering saturated air to the space.

Dear friend kindly tell me the desplacement thats the volume of water in litre/mint.then i can tell you about that.

e.mail akamal22000@yahoo.co.uk

GO TO KELE.COM AND SIZING WIZARD. IT WILL ALSO CALCULATE THE CV AND MATCH YOU WITH THE VALVE MODEL NUMBER. YOU WILL HAVE ACCESS TO EVERYTHING INCLUDING LIST PRICE. YOU NEED AND ACCOUNT TO GET A MULTIPIER.

IF YOU DON'T KNOW YOUR FLOW RATE IN GPM CONTACT ME AT MY E-MAIL AND I'LL GIVE YOU A HAND. WE DO THIS EVERY DAY AND IT'S QUITE SIMPLE.

CONWAYMECH@YAHOO.COM

thank you Ill try kele and else Ill be contacting you