Cashco PBE-L Pressure Build Economizer - Manual (Page 2)

IOM-PBE-L 2
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 opposes di a phragm movement. As
SECTION III
IV. STARTUP
SECTION IV
De ter mine if the regulator is fl owing. If not, slowly
rotate the regulator adjusting screw clockwise
(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 screw CW to increase outlet
pressure, or CCW to reduce outlet pressure.
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
by greater than 10%; i.e. 20-80 psig (1.38-5.52
Barg) range spring. (Example: at low fl ow the
outlet pressure should not exceed 88 psig (6.07
barg), if it does, con sult factory).
C AUTION
outlet pressure drops, the range spring pushes
the dia phragm down, opening the port; as outlet
pres sure in creas es, the diaphragm pushes up
and the port opening clos es.
2. A complete diaphragm failure will cause the reg u-
la tor to fail open.
V. SHUTDOWN
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.
SECTION V
CAUTION
The maximum outlet pressure is list ed on the name plate
as the upper range spring pres sure level, and is the rec om -
mend ed "upper operative limit" for the sens ing diaphragm
(See Section IV. Startup, Step 7). Higher press ures could
dam age the di a phragm. (Field hydro static tests fre quent ly
de stroy dia phragms. DO NOT HYDRO STATIC TEST THRU
AN IN STALLED UNIT; ISO LATE FROM TEST.)
CAUTION
Do not walk away and leave a bypassed reg u la tor unat-
tended.
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 the range spring by turning the adjusting
screw counter clockwise (CCW) a minimum of
three (3) full revolutions. This reduces the outlet
(down stream) pres sure set point.
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.