12. Safety Valves

12. Safety Valves
All these valves have simple, adjustable spring loaded relief balls/surfaces that progressively release pressure when the setting is passed. They are not "pop" valves that trigger at a set pressure. When calibrating them as per instructions, the set pressure is what is showing on the gauge when steam is first released. If heating continues the volume of steam ejected will increase. There are 3 designs that are matched to a variety of situations for 2”, 3” & 4” boilers.

Adjusting the operating pressure:
P/N’s 4131 & 4027 are screwed into the boiler barrel and can be adjusted by loosening the lock nut on the top of the valve and turning the nut inside it shown above each type. The inside nut of P/N 4131 has a slotted head while P/N 4027 has four holes best moved with small pointed tweezers.
P/N 4132 must be removed from the boiler, the lock nut on the shaft loosened with a spanner and the adjustment made on the adjusting (second) nut.

Obviously care must be taken to tighten the locking nuts after an adjustment.

Recommended operating pressures for each size of boiler are
2” 25 psi       3” 35 psi       4” 45 psi.

Note that the appropriate setting is NOT made at the factory– it must be set by the user as part of the commissioning process as the setting can vary depending on location.