Install Instructions

3
Procedure
1) Adjust the Range Screw/Pointer to the desired "High Event"
setting.
2) Adjust the Differential screw to the desired differential.
Low Event = High Event – Differential
✧ Adjustment of the Range Screw changes both high and
low events.
✧ Adjustment of the Differential Screw changes the "Low Event"
only.
SETTINGS & ADJUSTMENTS
Adjustable Range & Differential Controls
Adjustable Range Fixed Differential Controls
or High Side Dual Pressure
Controls may have external
adjustments (shown), or internal
adjustments. If the control has
internal adjustments, the cover
must be removed to access the
adjustment screws.
Procedure
1) Adjust the Range Screw to the desired "High Event" setting.
Low Event = High Event – Fixed Differential
✧ Adjustment of the Range Screw changes both the high and
low events.
Do not set the Low Event below the lowest allowable event
Low Event – High Event = Differential
Lowest Allowable Events
Low Pressure Control = 27" Hg
High Pressure Control = 50 PSIG
CONTROL SETTING & CHECKOUT
❍ Low Pressure Controls – With an accurate pressure gauge
attached to the suction service valve, slowly close the liquid
line valve to allow the system to pump down.
Observe the control's Low Event Switching Pressure – slowly
open the liquid line to allow suction pressure to rise. Observe
the control's High Event Switching Pressure – adjust the
control range and differential set points as required to
achieve the desired settings.
❍ High Pressure Controls – With a high pressure gauge
attached to a high pressure service port, restrict the air flow
thru an air-cooled condenser, or reduce the water flow thru a
water-cooled condenser to cause discharge pressure to rise.
Observe the control's High Event Switch Point and adjust as
necessary. Restore normal cooling and observe the control's
Low Event Switch Point, adjusting as required.
Before leaving a new control installation, it is best to observe a minimum of 3 cycles to assure proper operation.
KNOB
KNOB
SCREW
FULL LOCKPLATE
LOCKS BOTH
RANGE &
DIFFERENTIAL
LOCKPLATE AND KNOB
The lockplate can be used to lock:
1. Both Range and Differential Screws. Neither setting can be
adjusted. To use lockplate options 2 or 3, break one end off
the lockplate along the creaseline (see exploded view
diagram at left).
2. Range Screw Only. Range screw is locked so that high event
is fixed – adjusting the differential screw allows low event only
to be changed.
3. Differential Screw Only. Differential is locked so that
differential is fixed – adjusting range screw moves both high
and low event up or down together.
NOTE: If only one screw is
locked, knob can be applied to
unlocked screw.
NOTE: The Range Screw(s) and
Lockplate attachment screw are
cross-drilled to allow the use of a
wire seal.
Lockplate Installation on Dual Pressure Control