Groth 1402 - Manual (Page 2)

1402revb.doc 1
The Groth Model 1402 pilot is a pressure
actuated 4-way valve that can be used to
control a single acting (push) or 2-way
(push-pull) pneumatic actuator. The pilot
can be actuated by pressure as low as 1.5
IN WC.
It is used with Groth pilot operated valves
(POV) when very low set pressure or a
non-flowing pilot is required. For further
information regarding the installation,
operation and maintenance of pilot
operated pressure/vacuum relief valves,
see the manuals for Groth 1660 or 1400
series valves.
The following section describes the use of
the 1402 pilot to control a 2-way (push-
pull) actuator, see figure 1.
Tank pressure is sensed by connecting the
“sense” port to the pressure pick-up
fitting in the POV or directly to the tank
vapor space. If tank pressure is used to
operate the POV, this port will also be
connected to the pilot “supply” port by a
factory-installed tube.
The 1402 pilot can utilize an independent
supply (air, nitrogen, etc.) up to 1 PSI to
operate the POV. In this case, the
independent supply is connected to the
pilot “supply” port.
The “upper dome” port of the pilot is
connected to the upper dome or “push”
chamber of the actuator. The “lower
dome” port of the pilot is connected to the
lower dome or “pull” chamber of the
actuator.
When tank pressure is less than set
pressure, the pilot spool remains in the
lower position. Supply pressure is
applied to the upper dome of the valve
actuator and the lower dome is vented
through the pilot spring bonnet vent.
There is no emission from the pilot.
When tank pressure exceeds the set
pressure, the pilot spool moves to the
upper position. Supply pressure is
applied to the lower dome of the valve
actuator and the upper dome is vented
through the pilot spring bonnet vent. The
only emission from the pilot is that
required to vent the actuator chamber
during valve opening or closing.
Figure 1