Brochure

N800-0555 Series

Positive Positioning Relay

Model Chart

The N800-0555 is used with M556 (6 in. stroke),

M573 (3 in. stroke), and M574 (4 in. stroke) damper

actuators.

The N800-0555 is pilot-operated, providing

excellent response to small signal pressure

changes from the controller.

Pilot-operation also provides maximum resistance

to actuator shaft displacement caused by outside

force changes.

Features:

A built-in adjustable needle-valve permits setting the desired

rate of actuator movement, helpful in two ways:

• Various size actuators operated by the same control signal

can be made to operate at approximately the same rate of

movement, since the smaller actuators can be slowed to

match the rate of movements of larger actuators. One

example: Outdoor, return and relief dampers of

Air-Handling-Units, where the return damper is frequently

smaller, and has a smaller actuator.

• Some rapidly changing processes are easier to control if

the actuator moves slowly. Examples:

- Duct static-pressure control.

- Duct air-velocity control.

- Control of the mixed-air-temperature of air-handling

units, where the mixed-air-temperature changes instantly

as the dampers change position. Since no sensor

responds instantly, more stable control can be attained if

the dampers move slowly. This, in turn, may allow use of

a narrower controller throttling range.

Actuators may be ordered with positioners mounted. For

field-mounting, feedback arm and spring must be ordered

separately. Refer to Model Chart.

Model No. Description

N800-0555-BOX Positioner only.

N800-0555-P

Positioner kit. Includes one positioner, one feedback arm, and 5 and 10 psi feedback springs for M556 (6 in.

stroke), M573 (3 in. stroke), and M574 (4 in. stroke).

800

0555

ries