Anderson Greenwood Spring Operated Pressure Relief Valve 81PS1F68-4

Two adjustments are provided on gas service valves, one for adjusting the opening pressure and one for adjusting the closing pressure

Turn spring adjustment screw on bonnet in most of the way. Increase pressure to desired level and back out screw until valve pops

Lock screw with jam nut and retest

To adjust blowdown, turn blowdown adjustment screw IN to shorten blowdown; OUT to increase blowdown

If the valve leaks after repair check the following!

1. Full and even seating of nozzle and guide

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

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);

Relieve spring tension and back blowdown adjusting screw out two turns

Remove inlet bushing, bushing seal and valve internals

Separate nozzle from guide by hitting top of spindle on soft surface

Hold spindle by skirt O.D. in soft jaw vise and replace seat

Examine nozzle and polish out any scratches or nicks. Replace if necessary

To obtain better seat seal with PTFE at low set pressures, burnish seat against nozzle by chucking spindle in lathe and holding nozzle against spindle. Burnish with small force and for short time as PTFE readily deforms