Potter Releasing Systems - Manual (Page 54)

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section of piping. When water flows into the system, it also flows into this port. The flow switch will operate
when the pressure reaches 6 psi. These devices do not need a retard as there should be no water surges. This
device does not need adjusting.
The waterflow switch will not trip until after the release panel goes into alarm and operates the release circuit
which opens the valve and allows water to flow into the system.
Low Air Pressure Switch: PS40-1, PS40-2, PS10-1, PS10-2
The pressure on single and double interlock systems must be monitored to ensure the integrity of the piping.
On double interlock systems, a low air switch with two switches can be used. One switch could be set to trip
first for a low air SUPERVISORY condition which would indicate a loss of air pressure possibly due to a failed
compressor. The other switch could be set to trip a few psi lower for the low air ALARM. Then when a smoke
or heat detector and the low air ALARM switch are both in alarm at the same time, the release panel will trip
the solenoid. On systems with 5-15 psi, the PS10-1 will provide a low signal at 4 psi. It can be adjusted to trip
between 4-15 psi. For systems with more than 15 psi, the PS40-2 will provide a low signal at 30 psi. It can be
adjusted to trip between 10-60psi. To change the pressure settings, remove pressure from the device. Adjust the
thumb wheel until the top of the wheel corresponds with the desired pressure setting on the scale. The switch
should trip at approximately that pressure on a drop. Pressure supervisory switches should have a bleeder valve,
model BVL installed in line for testing purposes.
Pre-Action (Single-Interlock) Systems
Pre-Action systems are basically dry pipe systems, except they use an electrically operated valve to hold
back the water supply instead of a dry pipe valve. They are designed to overcome the operational delay of
conventional dry pipe systems, and to eliminate the possibility of accidental water damage caused by accidental
damage to the sprinkler heads or system piping.
The water supply valve is operated independently of the opening of sprinklers. The valve is opened by the
operation of a releasing panel which is monitoring initiating devices such as smoke or heat detectors, not by the
fusing of sprinklers.
Single interlock systems use closed sprinklers attached to a piping system containing supervisory air pressure.
The water is held back by an electrically operated valve. The valve is connected to a compatible releasing panel.
The panel is monitoring initiating devices such as smoke or heat detectors, and manual stations, that are located
in the same area as the sprinkler heads. These devices are connected to the releasing panels alarm initiating
zones. A low air pressure supervisory switch is used to monitor the supervisory pressure in the piping system, it
is connected to a supervisory zone on the release panel.
If the system pressure drops due to an open sprinkler, damaged pipe, or air compressor failure, the pressure
switch will cause a supervisory condition on the release panel, the valve will not open. If the smoke or heat
detectors operate or if a manual station is activated, the release panel will go into an alarm condition, causing
the release circuit on the panel to energize which will allow the valve to open and water to flow into the system
piping, even if no sprinklers have opened.
Typical System Configuration (PFC-4410RC Program #1)
Initiating [ inputs ]
Zone #1 - Conventional Alarm Zone - Smoke or Heat detectors
Zone #2 - Conventional Alarm Zone - Smoke or Heat detectors
Zone #3 - Waterflow Zone - Pressure type waterflow switch
Zone #4 - Manual Station Zone - Pull Stations
Sup #1 - Supervisory Zone - Valve tamper and/or low air supervision
Sup #2 - Supervisory Zone - Valve tamper and/or low air supervision
Indicating (outputs)
#1 - General Alarm - Operates as soon as the panel detects an alarm condition.
#2 - Waterflow Bell - Operates when the waterflow switch detects water flowing into the system.
#3 - Release - Opens the Solenoid to allow water into the system after the panel goes into alarm.
#4 - Supervisory - Bell or horn to indicate a supervisory condition.