Manufacturer: Johnson Controls
Description: 9 SWITCH STEP CONTROLLER 120V
Category: Electrical Controls
Sub Category: Switches & Relays
The Johnson G-7185 Pneumatic Step Controller is
designed to regulate electric heating elements in
accordance with the demands of a direct acting,
single or dual temperature pneumatic thermostat.
The G-7185 is available with six or nine pressure
electric switches adjusted for sequence operation
within a nominal operating range of pilot pressure.
Each switch is rated at 20 amperes 480 volts A.C.
(non-inductive); 360 V.A., 120-480 volts A.C. pilot
duty. The G-7185 is U.L. component recognized.
The solenoid operated exhaust valve and a reverse
acting 2:1 cumulator are integral parts of the G-7185
and act as fail safe devices. If a power failure occurs
in the fan circuit, the solenoid valve exhausts the
control air from the switches returning them to their
normally open position.
For unit ventilator applications, 120 volts A.C. six or
nine point models are available with a line cord and
plug and 1/8 in. brass barbed fittings for supply and
pilot pressure connections.
The reverse acting cumulator varies its output
pressure inversely to the pilot air pressure changes
from the thermostat, at a 2:1 ratio. With full pilot
pressure from the direct acting thermostat to the
cumulator, the output pressure will be 0 psig and all
of the pressure electric switches will be de-energized.
As the temperature at the thermostat decreases, the
output pressure of the cumulator increases. When
the cumulator output reaches 6.5 psig, the switches
begin to close. The nine switch model closes in
steps of 0.8 psi and the six switch model in steps of
1.2 psi until all the switches are closed and all
heating elements are energized.
The G-7185 is furnished in a heavy gage metal
cabinet designed for unit ventilator end compartment
mounting or wall mounting in any position. Conduit
knockouts are provided in the top and bottom of the
Replaces Part Numbers: G-7185-5, CARG-7185-5