Open the accumulator blowdown valve (H).
When the steam pressure drops to zero, close the
coil drain valve (J) and the accumulator
blowdown valve (H).
Open the circulating feed valve (E).
To resume operation, allow the plant to fill with
water and start the burner in the normal manner.
You may have to reprime the circulating pump
after the blowdown. To prime the feedwater
pump, refer to the manufacturers instructions.
Additional inspection and maintenance factors for
the steam generator are as follows:
When the electric motor is equipped with sealed
bearings, the bearings are prelubricated for the
life of the bearings. However, motors equipped
with oil-wick-lubricated bearings should have 1
teaspoon of good grade oil added to the
reservoirs every 6 months.
If the motor is equipped with pressure grease
fittings, remove the plug below the motor shaft
every 6 months and force a light grade of grease
into the port at the top until the clean grease
appears at the plug outlet. To prevent rupture of
the grease seals, run the motor for 4 or 5 minutes
before replacing the plug below the motor shaft.
Every year (more often under severe
operations), drain and refill the water pump
crankcase with a good grade of SAE 20 motor oil
(about 5 quarts required). With the pump
running, oil should show at least halfway in the
The water pump check valves should also be
inspected and cleaned when you remove scale
from a restricted heating coil. Check the disks,
springs, and valve seats for scale and pitting.
The relief valve (fig. 5-21) of the water pump
should be adjusted to open at about 500-psi feed
pressure but remain driptight during operation.
Leakage from this valve results in a lack of water
to the heating unit and causes overheating.
Sometimes when the unit is started, the feed
pressure may temporarily rise enough to cause
the relief valve to release a small amount of
water; however, the feed pressure will return to
normal after the unit heats and the system
The water pump discharge snubber (fig. 5-22) is
nonadjustable. If the rubber insert has to be
Figure 5-21.Pump relief valve.
replaced, the old insert must be cut away from
the retainer. To ease assembly, lubricate the
new insert with glycerine (do not use oil) to
allow it to be pushed into the retainer and bottom
To keep the ring thermostat control of the
generator (fig. 5-23) at peak operation, you may
have to adjust the thermostat switch and the
thermostat ring channel. The plant must be
operated long enough to be thoroughly heated
before you adjust the thermostat switch. In
making these adjustments, refer to the
Adjust the thermostat ring channel (Number 23
of fig. 5-23) when replacing the heating coil or if
the original assembly has been disturbed. A
careful check of the adjustment must also be
made if the thermostat switch cannot be adjusted
without erratic response.
Figure 5-22.Water pump discharge snubber.