Model 1011
Installation and Operation Manual
14
Par
t No
. 51
2083 Dra
wing No
. 1
29-0205a 03/09
Set-up Procedure
Class I Purging Set-up
1. Close the enclosure pressure control regulator fully by
turning counterclockwise (CCW).
2. Temporarily connect the inert gas supply to a 0 to 250
SCFH flowmeter. Connect the outlet of the flowmeter to the
enclosure pressure control regulator.
3. Check operation of enclosure pressure vent (if utilized).
4. Seal enclosure(s) and adjust enclosure pressure control
regulator by opening slowly clockwise (CW) to set a “safe”
pressure on the enclosure pressure indicator.
NOTE: If pressure setting is difficult to stabilize or set,
see page 16, “Troubleshooting Procedures.”
5. When safe enclosure pressure is stabilized, measure flow
of inert gas supply through protection system, to calculate
required exchange time, based on the Class I exchange
time chart.
6. Install and tighten all bolts on the pressure loss alarm switch
(if utilized). Ensure the conduit is sealed with approved
compounds. Energize power to switch and alarm system (if
utilized) and test the function of the alarm system.
7. Cease testing and remove test equipment (flowmeter).
8. Connect the inert gas supply directly to the enclosure
pressure control regulator.
IMPORTANT NOTE: Operators must secure wrist or
stop watch to manually time exchange cycle for Class I
applications.
CLASS I VOLUME EXCHANGE TIME CHART
MEASURED FLOW
REQUIRED EXCHANGE TIME
0.10 SCFM / 6 SCFH
40 minutes per cubic foot
0.25 SCFM / 15 SCFH
16 minutes per cubic foot
0.50 SCFM / 30 SCFH
8 minutes per cubic foot
0.75 SCFM / 45 SCFH
5.5 minutes per cubic foot
1 SCFM / 60 SCFH
4 minutes per cubic foot
2 SCFM / 120 SCFH
2 minutes per cubic foot
3 SCFM / 180 SCFH
1.5 minutes per cubic foot
4 SCFM / 240 SCFH or greater
1 minute per cubic foot
NOTE:
The volume exchange time chart is based on a four (4)
enclosure volume exchange. Multiply the required exchange
time above by 2.5 for applications requiring a ten (10) volume
exchange (motors).
Regardless of enclosure volume or system flow rate, it is
required that operators withhold power to the enclosure
while inducing Class I exchange, for at least five (5) minutes.
Normal exchange time calculations should be doubled if large
obstructions block inert gas flow.
The start-up instruction nameplate exchange time slot will be
blank, but the unit may feature a set of direct factor nameplates
with self-adhesive backing such as “TEN MINUTES,” for
application to the start-up instructions, dependent on how the
system was specified and purchased. Field modification of
this nameplate, to show a direct factor, is acceptable as noted
above if the method used to mark the nameplate does not
deface the instructions listed. Materials used for the marking
must be indelible and withstand prevailing environmental
conditions.
Class II Pressurization Set-up
1. Close the enclosure pressure control regulator fully, by
turning it counterclockwise (CCW).
2. Remove all traces of combustible dust from the protected
enclosure.
3. Check operation of enclosure protection vent (if utilized).
4. Seal enclosure(s) and adjust enclosure pressure control
regulator by opening slowly clockwise (CW) to set a “safe”
pressure on the enclosure pressure indicator.
NOTE:
If pressure setting is difficult to stabilize or set, see
page 16, “Troubleshooting Procedures.”
5. Install and tighten all bolts on the pressure loss alarm switch
(if utilized). Ensure the conduit is sealed with approved
compounds. Energize power to switch and alarm system (if
utilized) and test the function of the alarm system.
HELPFUL HINTS
The term “Safe” pressure for purposes of this manual
is defined as follows:
Class I = a minimum .25 inch of water column pressure
Class II = a minimum 1.0 inch of water column pressure
Regulator may be in the locked position upon arrival. To
adjust regulator, pull handle to outward position.
To test the vent’s operation, gently prod the vent flapper
open with a soft-pointed object, ( example: eraser end
of a pencil) ensuring that the vent valve works freely. On
vertically configured vents, this can be accomplished
from within the protected enclosure. Side mounted
-90 configured vents can be tested by removing the
conduit plug at the bottom of the mounting tee. Multiple
operations require only one test per day if enclosure is not
opened or left unattended.
