Technical data

31.
Figure 33
MODEL A-2
Figure 34
MODEL B-1
2.4.2 Model B-1 Air Maintenance Device
The Reliable Model B-1 Pressure Maintenance Device is designed for use in conjunction with a tank-
less air compressor that does not have a pressure control switch to maintain the correct pressure in
the system. By wiring the compressor motor to the electrical pressure switch of the Model B-1 Device*,
the on/off operation of the compressor is controlled directly by the pressure in the system. A significant
decrease in air pressure closes the pressure switch contacts activating the compressor. The com-
pressor runs until the air pressure is restored to the pre-adjusted setting of the pressure switch. When
the pressure is satisfied, the switch contacts open and stop the compressor. The pressure switch on
the B-1 is equipped with an unloader valve that automatically bleeds off the air pressure between the
compressor outlet and the air maintenance device each time the pressure switch opens. This protects
the compressor motor from starting under a load the next time it starts. Like the Model A-2 Device, the
Model B-1 has a strainer for contamination control, a bypass valve for rapid fill, and shut off valves open
for ease of repairs to the device.
*Note: The switch on the B-1 Air Maintenance Device is NOT a low pressure alarm switch. When using
this device, a separate low air alarm switch is required.
Approvals and technical data for the Model B-1 Pressure Maintenance Devices can be found on Reli-
able Automatic Sprinkler Company Bulletin 254.
2.4.3 Model NS-Pak
The Reliable Model NS-PaK is designed to supervise nitrogen pressure for individual preaction and dry
pipe systems. The nitrogen supply is obtained from a high pressure nitrogen cylinder (or cylinders)
which are sold or rented separately. The NS-PaK includes a single stage pressure regulator equipped
with high pressure inlet and low pressure outlet gauges. As the nitrogen is gradually depleted and
the pressure inside the cylinder drops, the low pressure regulated output remains stable. The cylinder
pressure supervisory switch (System Sensor Model EPS40-2) is factory set to 90 PSI and monitors the
regulated pressure coming out of the nitrogen cylinders. The pressure switch provides notification to
the owner that the nitrogen cylinders are in need of replacement or refilling. The adjustable system
pressure supervisory switch (System Sensor Model EPS10-2) is factory set to 13 PSI and monitors the
system supply pressure.
Braided flexible hoses and adapters are provided for connection of the NS-Pak to the nitrogen regula-
tor and the system. All components are conveniently cabinet mounted, and a quick by-pass segment is
incorporated on the NS-PaK to reduce set up time. The Model NS-PaK Panel is designed with keyhole
slots for ease of wall mounting.
Approvals and technical data for the Model NS-Pak Panel can be found on Reliable Automatic Sprin-
kler Company Bulletin 254.