7
Putting the Humidifi er Into Operation
When Temperature Switch is Employed
simply set hu-
midity controller at desired level, and turn on the steam.
When Temperature Switch Is Not Employed
deactivate
operator control so that humidi
fi
er control valve will remain
closed. Then:
A. Open steam supply valve, to bring humidi
fi
er up
to
temperature.
B. When drain line from humidi
fi
er is at steam
temperature, activate the operator control.
C. Set desired relative humidity.
After the Humidifi er Is In Operation
Clean Strainer.
The screen in the strainer installed in the
steam supply line should be cleaned a few days after the
humidi
fi
er is placed in operation, and thereafter at least
once each season – more often if you
fi
nd much dirt in the
screen.
Check Trap.
The steam trap is used to drain the humidi-
fi
er should be inspected at the same time the strainer is
cleaned.
Trouble Shooting FSA, VSA
Humidifi er Will Not Discharge Steam
A. –Solenoid Fails to Open
1.
Burned
out
coil.
2.
Humidistat
at
fault.
3.
Hand
switch
open.
4. Dirt in plunger tube or bent tube.
5. Steam pressure too high for unit as
furnished.
6.
*Damaged
piston
ring.
7. *Plugged or restricted pilot ori
fi
ce.
B. -Steam System Malfunction:
1. Silencing chamber plugged with dirt.
Remove and replace silencing material and
retainer.
2.
Strainer
screen
plugged.
3. Dirt in steam line.
4. Steam valve closed in line to humidi
fi
er.
5. Pressure reducing valve out of order.
*FSA-92 and FSA-93, VSA-92 and VSA-93 only.
Humidifi er Discharge Water
A.
–Faulty
Installation:
1.
Long,
untrapped
supply
line.
2.
Humidi
fi
er supply from bottom or side of
steam
header.
3. Untrapped valve in vertical, downfeed
supply
line.
B.
–Faulty
Drainage
1.
Steam
trap
fi
lled with dirt.
2. Return line pressure above humidi
fi
er
pressure.
3. Too much vertical lift.
4. Wrong type of trap used.
5. Second trap short circuiting the
humidi
fi
er trap.
Operation and Servicing
Humidifi er Discharges Continuously, Even though
Humidity Has Reached Desired Level:
A.
–Mechanical
Trouble:
1. Humidistat fails to open (points frozen).
2. Dirt holds solenoid plunger in open position.
3. Bent solenoid tube holds plunger in open
position.
4. Dirt between valve and seat.
5.
Coil
not
de-energized.
6.
Damaged
spring.
7.
Plugged
bleed
hole.
B.
–Insuffi cient Capacity:
1. Not enough units to give desired relative
humidity.
Trouble Shooting AM, AMAF, AMEF
Humidifi er Will Not Discharge Steam
A. –Control System At Fault:
1. Faulty control valve operator.
2.
Faulty
humidity
controller.
3. Faulty connections between humidity
controller and control valve operator.
4.
Air
valve
closed.
B. –Steam System Malfunction:
1. Silencing chamber plugged with dirt.
Remove and replace silencing material and
retainer.
2. Strainer screen plugged.
3. Dirt in steam line.
4. Steam valve closed in line to humidi
fi
er.
5. Pressure reducing valve out of order.
Humidifi er Discharges Water
A. –Faulty Steam Supply:
1. Long, untrapped supply line.
2.
Humidi
fi
er supply from bottom or side of
steam
header.
3. Untrapped valve in vertical, down feed
supply
line.
4.
Boiler
carryover.
B.
–Faulty
Operation:
1. Faulty temperature switch.
2. Humidity controller set up before humidi
fi
er
has reached steam temperature.
C.
–Faulty
Operation:
1. Faulty temperature switch.
2. Humidity controller set up before humidi
fi
er
has reached steam temperature.
Humidifi er Discharges Continuously Even Though
Humidity Has Reached Desired Level.
A. –Humidity Controller Out of Calibration.
B. –Trouble in Humidifi er:
1. Valve stem “frozen” to stem seal due to
unusual chemical or corrosive conditions in
steam
system.
2.
Operator
spring
broken.
3. Dirt or scale between valve and seat.
