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Product Description Model YZ104

Model YZ104 is a Type Y or Z pressurization unit designed Type Y & Z Purging
to protect electrical equipment in Class I Hazardous Areas.
When connected to a supply of protective gas and utilized in & Pressurization Unit
conjunction with a Model PV-4 Spark Arresting Purge Vent, the
Model YZ104 will supply, regulate and monitor the protective
gas supply to a protected electrical enclosure and accomplish Class I Applications
purging of the protected enclosure in an expedited manner.
Type Z applications reduce the hazardous area rating inside the Up To 250 Cubic Feet
enclosure from Division 2 / Zone 2 to Unclassified. This allows
general purpose equipment to operate in Division 2 / Zone 2
areas. Type Y applications reduce the hazardous area rating Technical Bulletin YZ104 TB-R0 © 07.23.2018
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 / Zone 1 Hazardous Areas.

Unit Operation

Prior to Start-Up: Ensure Protected Enclosure Power is
OFF, Protective Gas Supply is ON, Filter Regulator is set to
60 PSI, and alarm system is activated (if utilized). Test Purge
Vent for proper operation. Start-Up: Close and seal Protected
Enclosure. Open Enclosure Pressure Control Valve until a
“Safe” reading is shown on the Enclosure Pressure Gauge.
Open Purge Control Value and allow unit to purge protected
enclosure for the required time marked on Unit Start Up
Instructions or for 5 minutes, minimum and then close Purge
Control Valve. Confirm protected enclosure “Safe” pressure
is stable. Energize protected enclosure equipment. Loss of
“Safe” pressure requires immediate attention. De-energized
power if “Safe” pressure cannot be restored within a reasonable
amount of time.
Product Specifications

Maximum Enclosure Volume: 250 cubic feet
Universal Unit Weight: 14.0 lbs.
Vertical & Horizontal Unit Weights: 17.5 & 18.0 lbs.
Operating Temp. Range: -20° F - 120° F Universal Mount Unit
Protective Gas Supply: * Air or Inert Gas less Pressure Switch for
Unit Supply Pressure: 80 - 125 psi maximum any side or panel mounting
Unit Supply Connection: 1/2” tube fitting
Enclosure Supply: 1/2” tube fitting
Enclosure Reference: 1/4” tube fitting
Safe Enclosure Pressure: 0.25” w.c.
Safe Pressure Flow Rate: ** 0.1 - 3.5 SCFH per cubic foot
Purging Enclosure Pressure: ** 5” - 8” w.c.
Purging Flow Rate: 30 SCFM / 1800 SCFH @ 60 psi
4 Volume Purge Time: 1 minute per 7.5 cubic foot
5 Volume Purge Time: 1 minute per 6.0 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 and
purging enclosure pressure.

Required Accessory

A Model PV-4 Spark Arresting Vent is required for proper operation
of the purging cycle and to protect the enclosure from excessive Vertical Mount Unit
pressure of the protective gas supply in accordance with the with Pressure Switch for
requirements of NFPA 496, EN 50016 and IEC 60079-02.
left or right side mounting
Best Purging Systems Corporation therefore requires the purchase of Horizontal Mount Unit
a Model PV-4 Spark Arresting Purge Vent with this unit for installation with Pressure Switch for
on the protected enclosure or the last enclosure of an enclosure array. top or bottom side mounting

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