Emerson Anderson Greenwood 81 Series - BLOWDOWN ADJUSTMENT; Turns out of blowdown screw; 5 SEAT LEAKAGE; 5.1 General

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ANDERSON GREENWOOD SERIES 81 SPRING OPERATED PRESSURE RELIEF VALVES

INSTALLATION AND MAINTENANCE INSTRUCTIONS

5 SEAT LEAKAGE

5.1 General

If the valve leaks after repair check the following:

5.1.1 Full and even seating of nozzle and guide.

5.1.2 Foreign particles trapped between the

seat and nozzle. If any are found they

may have damaged the seat, making it

necessary to replace it.

5.1.3 Correct seat material for the valve

set pressure.If items 1 and 2 reveal

no evident seat leakage source, the

procedures described in Section 5.2 may

be used to eliminate seat leakage. Section

5.2 applies only to teflon seated -4, -6, or

-8 orifice Series 81’s with nameplate set

pressures that do not exceed 300 psig

(2068 kpag).

5.2 Seat sealing procedures

Heat the valve for 15 to 30 minutes in a

oven preheated to 250-300°F (121-149°C).

Aconcentrated heat source such as a heat

gun or open flame must not be used. After

the valve has air-cooled to room temperature,

retest per Section 4.0 to insure seat tightness.

If results have not improved, the valve should

be disassembled and the seat replaced.

6 SET PRESSURE CHANGE

If the set pressure is changed more than ±5%

from the nameplate set pressure, the spring,

spring washers, spring bonnet, guide plugs and

seat may also have to be changed. Consult the

factory or refer to the soft goods repair kit, the

table in Section 3.3 and spring chart 03.0079.

BLOWDOWN ADJUSTMENT

Set pressure range

Orifice Turns out of blowdown screw psig kpag

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Emerson.com/FinalControl

-4 1 20-4000 138-27579

1½ > 4000 > 27579

-6 ¾ 20-1410 138-9722

1¼ > 1410 > 9722

-8 1½ 20-600 138-4137

2½ > 600 > 4137

-F 1 20-700 138-4826

1½ > 700 > 4826

-G 1¾ 20-700 138-4826

2¼ > 700 > 4826