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Product Description Model YZ101B

Model YZ101B is a Type Y or Z pressurization unit designed Type Y & Z
to protect electrical equipment in Class II Hazardous Areas.
When connected to a supply of protective gas, the Model Pressurization Unit
YZ101B will supply, regulate and monitor the protective gas
supply to a protected electrical enclosure. Type Z applications
reduce the hazardous area rating inside the enclosure from Class II Applications
Division 2 / Zone 2 to Unclassified. This allows general purpose
equipment to operate in Division 2 / Zone 2 areas. Type Y Up to 50 Cubic Feet
applications reduce the hazardous area rating inside the
enclosure from Division 1 / Zone 1 to Division 2 / Zone 2. This
allows Division 2 / Zone 2 equipment to operate in Division 1 Technical Bulletin YZ101B TB-R0 © 07.23.2018
/ Zone 1 Hazardous Areas.
Unit Operation

Prior to Start-Up: Ensure Protected Enclosure Power is OFF,
Enclosure Pressure Control Regulator is closed, Protective
Gas Supply is ON and alarm system is activated (if utilized). If
utilized, test Purge Vent for proper operation. Start-Up: Remove
all dust from protected enclosure. Close and seal Protected
Enclosure. Open Enclosure Pressure Control Regulator until
a “Safe” reading is shown on the Enclosure Pressure Gauge.
Energize protected enclosure equipment. Loss of “Safe”
pressure requires immediate attention. Protected enclosure
power should be de-energized if “Safe” pressure cannot be
restored within a reasonable amount of time.
Unit Specifications

Class II Maximum Enclosure Volume: 50 cubic feet
Universal Unit Weight: 5 lbs.
Vertical & Horizontal Unit Weights: 9.0 & 9.5 lbs.
Operating Temp. Range: -20° F - 120° F
Protective Gas Supply: * Air or Inert Gas
Supply Pressure w/ RR-6 Regulator: 5 psi maximum
Supply Pressure w/ PV-3 Vent: 80 - 125 psi maximum
Unit Supply Connection: 3/8” tube fitting
Enclosure Supply: 3/8” tube fitting Universal Mount Unit
Enclosure Reference: 1/4” tube fitting less Pressure Switch for
Safe Enclosure Pressure: 0.25” w.c. any side or panel mounting
Safe Pressure Flow Rate: ** 0.1 - 3.5 SCFH per cubic foot
Switch Set Point on Decrease: 0.15” w.c. ± 0.02”
Pressure Switch Conduit Port: 1/2” FPT
Pressure Switch Contact Ratings: See EPSK Bulletin
* Air must contain no more than trace amounts of flammable vapors.
** Enclosure integrity determines safe pressure flow rate.

Recommended Accessories

Redundant safety devices are necessary to protect the enclosure
from excessive pressure of the protective gas supply in accordance
with the requirements of NFPA 496, EN 50016 and IEC 60079-02.
Best Purging Systems Corporation therefore strongly recommends
a Model RR-6 Redundant Regulator installed upstream of this unit’s
enclosure pressure control regulator. As an alternative, a Model
PV-3 Spark Arresting Purge Vent may be installed on the protected
enclosure or the last enclosure of a pressurized enclosure array to
relieve excessive pressure created by other sources.
Vertical Mount Unit
with Pressure Switch for
left or right side mounting
Horizontal Mount Unit
with Pressure Switch for
top or bottom side mounting

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