CRD PILOT/ Pressure Regulating/Sustaining Valve

Question 1

…. will keep water from going on to valve bonnet. Water already on valve bonnet will flow off through control tubing. Upstream psi pushes up on diaphragm of valve, fully opening valve.

…. doing so will over-pressure the downstream (wanted regulated) pressure zone. Bad deal.

How to fully open reg valve?

Answer 1

Closing upstream cock on PRV valve ( with CRD)

Question 2

…. Will keep water from flowing off bonnet through control tubing, thereby allowing water to build up on bonnet and closing valve.

With valve controls, How to close reg valve?

Answer 2

Closing downstream cock on PRV with CRD.

Question 3

Normal position for CRD PILOT

Answer 3

…. Normally open

…. the spring tension/pressure pushes the pilot open. When water enters pilot, the pilot will close once the water psi overcomes the spring psi.

Question 4

CRD is meant to maintain ….(upstream/downstream)….

pressure on the valve, regardless of ______ pressure/fluctuations/ or flow

Answer 4

….. downstream pressure

Regardless of upstream pressure Fluctuations or downstream flow rates (downstream gpm)

Question 5

As flow rate (gpm) decreases , psi ________?

Answer 5

Increases

Question 6

As psi increases, flow rate (gpm) _______?

Answer 6

Decreases

Question 7

Valve will Modulate _____ as downstream flow(gpm) increases/=/downstream pressure drops.

“ Drop in outlet psi, CRD will ____”

“ Valve/CRD will modulate _____ to get back to maximum downstream set point”

Answer 7

Valve will modulate open

Question 8

As demand decreases /=/ downstream psi increases valve will modulate ______.

“Rise in outlet psi, CRD will ______”

Answer 8

Valve modulates close

CRD will close

…. once downstream demand( flow/gpm) decreases, and downstream pressure builds up and meets the CRD set point, CRD sees system is satisfied and will close.

Question 9

Turning in CRD pilot stem will ____increase/decrease_____ psi on downstream side.

Answer 9

Increase

…. Turning CRD PILOT stem in, will actually open the CRD and increase pressure.

Question 10

Silent sparrow

Why did we increase downstream set point on 8inch reg valve?

Answer 10

…. if there is a drop in outlet/downstream pressure, valve will open to maintain pressure”

Downstream/outlet pressure dropped because demands/gpm increased, little 3inch reg was set up, and couldn’t flow enough water to keep up with demands and maintain pressure set point. We reset 8inch reg to maintain higher downstream pressure, making it open sooner. To help 3inch reg maintain pressure and keep up with demand.