Crown Boiler BSI172 - Manual (Page 25)

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16) Check the manifold pressure and adjust if necessary. To do this, use the following procedure:
a) Connect a manometer to the inlet pressure tap on the gas valve (see Figures 23 and 24).
b) Check the inlet pressure with all gas appliances on and off. The inlet pressure at the boiler must be within the
following limits regardless of what combination of appliances is firing:
Inlet Press (inches w.c.) Natural Gas LP Gas
Min. 5.0 11.0
Max. 14.0 13.0
If the inlet pressure falls outside of these limits, find and correct the cause of the problem before proceeding further.
c) Connect a manometer to the manifold (outlet) pressure tap on the gas valve (see Figures 23 and 24).
d) Read the manifold pressure. It should be set at:
Natural Gas LP Gas
Manifold Press. (inches w.c.) 3.5 10.0
e) If a manifold pressure adjustment is needed, make the adjustment by turning the pressure regulator (see Figures 23
and 24) screw clockwise to raise the pressure and counter clockwise to reduce the pressure. If a manifold pressure
adjustment is made, recheck the line pressure to be certain that it is still within acceptable limits. Replace the cover
screw on the regulator.
WARNING
FAILURE TO FOLLOW THE FOLLOWING PROCEDURE EXACTLY COULD RESULT IN OVER-FIRING OF
THE BOILER AND A CARBON MONOXIDE HAZARD.
FIGURE 20: STANDING PILOT
BURNER FLAME
FIGURE 21: INTERMITTENT IGNITION
PILOT BURNER FLAME