5
equals the input pressure. A decrease in the input pressure will
allow the output pressure to force the center assembly upward,
opening the exhaust valve until the output pressure is equal to
the input pressure.
A. BIAS ADJUSTMENT:
With normal supply pressure and input (signal) pressure
applied, the Bias Adjusting Screw (Figure 2) may be turned
clockwise to increase the output (control) pressure or
counterclockwise to decrease output pressure.
B. RATIO ADJUSTMENT:
The ratio of input to output pressure may be adjusted by
adjusting Valve Seat (17) as follows (see Figure 3 except
The simplified design of this relay makes routine maintenance
unnecessary. However, should the air or air lines be dirty, it
may be necessary to clean the surfaces of the Valve (18) and
the Valve Seats (A) and (B). If continued difficulty is
experienced from dirt, moisture, oil, etc., suitable filters should
be provided in the supply lines.
If the control pressure does not go below 0.5 psi with the Bias
Spring (Figure 2) in the null position, or if the exhaust appears
to be leaking (refer to Figure 3 except as noted) and follow the
instructions below:
1. Remove the Cap (24) and Spring Retainer (20) by
unscrewing from the Cover (22). Note position of Spring
Retainer (20) before removing so that it can be replaced in
approximately the same position. The Valve (18), Valve
Spring (19) and Gasket (23) are now free to fall out. Be
careful not to drop the parts.
2. Using a CLEAN, soft brush, cloth or paper, wipe off the
Valve Seats (A) and (B).
3. Inspect both Hemispherical Surfaces (C) of the Valve (18)
for dirt, chips, etc. If any scars or imperfections are
apparent, the Valve (18) should be replaced.
4. Replace the Valve (18), Valve Spring (19), Spring
Retainer (20), Gasket (23) and Cap (24). Be sure that the
Spring Retainer (20) is in the same position as it was in
before disassembly, approximately one turn below being
flush with end of Adjustable Seat (17) and that the Cap
(24) is tight. Check Cap (24) for external leakage.
5. Adjust per Section IV if needed.
DO NOT USE ANY GASKET SHELLAC, PIPE
COMPOUND, OR OTHER SEALANT.
To adjust the bias for an advanced or retarded output, turn the
adjusting screw clockwise or counterclockwise respectively,
to change the force exerted by the biasing spring.
where noted):
1. With a supply pressure of 30 psig and an input pressure
of 3 psig, turn Bias Adjusting Screw (Figure 2) until
output pressure is 3 psig. Increase input pressure to 15
psig and check output pressure, which should be 15 ±0.2
psig.
2. If necessary, remove Cap (24) and adjust Valve Seat (17)
until the correct output pressure is obtained.
3. Repeat steps 1 and 2 until the correct ratio is obtained.
This unit may be adjusted while operating with Cap (24)
removed, but the final setting must be checked after the
Cap (24) has been replaced.
SECTION IV - ADJUSTMENTS
SECTION V - MAINTENANCE
