Allmand — Inline External Relief Valve Adjustment
Adjustments · Inline external relief valve (port relief)
From a Allmand service manual covering: M-250 Series, M-258, M-259, M-301, M-303, M-304, M-310, M-311, M-313, M-314, M-319, M-326…. Check it applies to your exact model before use.
Procedure
- Dead head the port in question.
- Tee a gauge into the port, start pump, and note pressure.
- If pressure too high, turn adjusting screw counterclockwise using 1/4 inch allen key.
- If too low, turn adjusting screw clockwise a turn and note pressure gauge reading.
- If it does not move, turn screw counterclockwise, start pump, and flush dirt past ball.
- Turn screw to proper pressure setting.
Tools required
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Source: Allmand service manual. Steps and values are as documented; always cross-check against the official manual and any later revisions for your exact serial number before servicing.