Cashco 5381 - Manual (Page 2)

2 IOM-5381
SECTION III
III. PRINCIPLE OF OPERATION
1. Movement occurs as pressure variations regis-
ter on the diaphragm. The registering pressure
is the outlet, P
2
, or downstream pressure. The
range spring op pos es diaphragm movement. As
outlet pressure drops, the range spring pushes
the di a phragm down, opening the port; as outlet
pres sure in creas es, the diaphragm pushes up
and the port opening closes.
2. A complete diaphragm failure will cause the reg u -
la tor to fail open.
SECTION IV
1. Start with the block valves closed. A bypass
valve may be used to maintain outlet pressure
in the down stream system without changing the
fol low ing steps.
2. Relax the range spring by turning the adjusting
knob (30) counter clockwise (CCW) a min i mum of
three (3) full revolutions. This re duc es the outlet
(down stream) pressure set point.
3. If it is a “hot” piping system and equipped with
a bypass valve, slowly open the bypass valve
to pre-heat the system piping and to allow slow
ex pan sion of the piping. Assure proper steam
trap operation if installed. Closely monitor outlet
(down stream) pres sure via gauge to assure not
over-pressurizing. NOTE: If no bypass valve is
in stalled, extra caution should be used in starting
up a cold system; i.e. do everything slowly.
4. Crack open the outlet (downstream) block
valve.
5. Slowly open the inlet (upstream) block valve ob-
serv ing the outlet (downstream) pressure gauge.
De ter mine if the regulator is fl owing. If not, slowly
rotate the regulator's adjusting knob clock wise
(CW) until fl ow begins.
6. Continue to slowly open the inlet (upstream)
block valve until fully open.
7. Continue to slowly open the outlet (downstream)
block valve, especially when the downstream
pip ing system isn't pressurized. If the outlet
(down stream) pressure exceeds the desired
pres sure, close the block valve and go to Step
2, then return to Step 4.
8. When fl ow is established steady enough that the
outlet (downstream) block valve is fully open, be -
gin to slowly close the bypass valve if installed.
9. Develop system fl ow to a level near its expected
normal rate, and reset the regulator set point by
turning the adjusting knob CW to in crease outlet
pressure, or CCW to reduce outlet pres sure.
10. Reduce system fl ow to a minimum level and
ob serve set point. Outlet pressure will rise from
the set point of Step 9. The maximum rise in
outlet pressure on decreasing fl ow should not
exceed the stated upper limit of the range spring
by greater than 10%; i.e. 20-80 psig (1.38-5.52
Barg) range spring, at low fl ow the outlet pressure
should not exceed 88 psig (6.07 Barg), if it does,
consult factory.
IV. STARTUP
1. On systems with a bypass valve, and where sys-
tem pressure is to be maintained as the reg u la tor
is shut down, slowly open the bypass valve while
closing the inlet (up stream) block valve. Fully
close the inlet (upstream) block valve. (When on
bypass, the system pressure must be constantly
observed and manually regulated. Close the
outlet (down stream) block valve.
V. SHUTDOWN
SECTION V
2. If the regulator and system are to both be shut
down, slowly close the inlet (upstream) block
valve. Close the outlet (downstream) valve only
if reg u la tor re mov al is re quired.
Do not walk away and leave a bypassed
regulator unattended.
CAUTION