User Manual

4
Figure 5 - Temperature Pilot controlling on Instantaneous Heater in
conjunction with a Differential Pressure Pilot. Acts as Pressure Limiting
Device. Provides anticipating action - 1:1 ratio, air/steam.
VALVE TYPE
VALVE
ACTION
STARTS TO
TRAVEL AT
FULL TRAVEL AT: REMARKS
Diaphragm
Control Valves
Air-to-Open
Air-to-Close
3 psig 15 psig or other
Maximum air pressure
determined by pressure
drop.
In control Valves required air pressure
values may vary with pressure drop
variations.
Internal Pilot
Piston Operated
Valves (Class
LTY, LTPY,
etc.)
Air-to-Open Between 8 & 10 psi
on diaphragm
At air loading pressure
required for controlled
pressure plus opening
pressure. Flow depends
on system demand.
Valve produces approximately 7 psig
delivered controlled pressure per 1
psig additional loading pressure
supplied after opening force is applied.
Max. loading pressure 35 psig.
Fluid loaded
diaphragm
operated valves
(Class GPK,
etc.)
Air-to-Open Opening pressure
depends on pressure
drop and valve size.
See chart Figure 7,
Instruction RVI
7a/12a.
Air at loading pressure
required for controlled
pressure plus opening
pressure.
Valve produces 1 psig delivered
controlled pressure per 1 psig loading
pressure supplied after opening force
is applied.
Figure 4 - Temperature Control
System using Temperature Pilot as
Air Temperature Transmitter.
NOTE: Satisfactory where pressure
limiting is not required.
NOTE: Place thermal bulb as close to heater outlet as possible but not in
heater unless it is designed for that purpose.