Cashco P7 - Manual (Page 2)

IOM-P7 2
SECTION IV
IV. STARTUP
SECTION V
V. SHUTDOWN
SECTION III
III. PRINCIPLE OF OPERATION
1. Movement occurs as pressure variations regis-
ter on the piston (5). The registering pressure
is the outlet, P
2
, or downstream pressure. The
range spring (28) or loading pressure (for dome
loaded or ratio loaded designs) opposes piston
(5) move ment. As outlet pressure drops, the
range spring (28) or loading pressure push es the
piston (5) down, opening the port; as outlet pres-
sure in creas es, the piston (5) push es up and the
port opening clos es.
2. A complete piston (5) failure will cause the reg u la -
tor to fail open.
For Spring Loaded Design the maximum outlet pres-
sure is indicated on the body as the upper range
spring pres sure level, and is the rec om mend ed “upper
operative limit” for the sens ing piston (see Sec tion IV.
Startup, Step 7).
For Dome & Ratio Loaded Design the max outlet pres-
sure is 1500 psig (103.4 barg).
Max loading pressure for Ratio Loaded Design is 105
psig (7.2 barg).
DO NOT HYDRO STATIC TEST THRU AN IN STALLED
UNIT; ISO LATE FROM TEST.
CAUTION B
1. Start with the block valves closed. A by pass
valve may be used to maintain out let pres sure
in the down stream sys tem without changing the
fol low ing steps.
2. Relax range spring (28) by turning the knob (38)
counter clockwise (CCW) until ro ta tion comes to
a complete stop; or remove the loading pressure
for dome loaded or ratio loaded designs.
3. If it is a “hot” piping system, and equipped with
a bypass valve, slowly open the bypass valve
to preheat the system piping and to allow slow
ex pan sion of the piping. Closely monitor outlet
(down stream) pres sure via gauge to ensure 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 knob (38) clock wise (CW) or
increase the loading pressure 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, reset the regulator set point by turning
the knob (38) (CW) to increase outlet pressure or
(CCW) to reduce outlet pressure. Adust the load-
ing pressure for dome or ratio loaded designs.
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 up per limit of the range spring (28) by
greater than 10%; i.e. 2-100 psig (.14-6.9 Barg)
range spring (28).
Do not walk away and leave a bypassed
regulator unattended.
CAUTION C
1. On systems with a bypass valve, and where sys-
tem pressure is to be main tained 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 (up stream) block valve. (When on
bypass, the sys tem pres sure must be con stant ly
observed and man u al ly reg u lat ed. Close the
outlet (down stream) block valve.
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 required.