8
e)
Check function of field-installed safety controls,
such as the fan proving switch. Contactor(s) should
drop out when the proving switch is "open."
f)
Check heater draw by testing and recording voltage
and amperage in each phase. Readings should
match name plate readings; name plate is located on
the humidifier housing.
g)
Inspect installations for steam or air leaks while
operating the humidifier. Any leaks should be
sealed.
Inspect after first three months of duty. The best way to
determine how often your particular system will need
maintenance is to remove the cover and inspect it after
its first three months of duty. Potable water carries a
variety of minerals and other materials in a mix that varies
from location to location. This variation in water quality,
combined with the hours of operation and duty cycle, will
determine your own unique maintenance schedule.
Water quality makes a difference
1.
Light to moderately hard water (2 to 10 grains/gallon
or 34.2 to 171 mg/1 hardness)
•
annual cleaning
2.
High mineral content water (more than 10 grains/
gallon or 171 mg/1 hardness)
•
cleaning frequency determined by use and water
quality
•
periodic drain and flush cycles
3.
DI/RO water (Model VMDI)
•
no regular cleaning required (although regular
inspections are advised)
•
no drain and flush cycles required
•
the presence of chlorides in DI water will
eventually cause pitting and failure of the tank
and its components
4.
To dramatically reduce mineral accumulation inside
the evaporating chamber, softening of the makeup water
recommended. (Solids like silica are not removed in the
the softening process.)
START-UP AND OPERATION
Test Cycling the Drain/Flush System
The level control board contains four pairs of terminal
pins which are marked 20, 40, 80 and “T” (TEST). To
test:
1.
Pull the pin block off the pair of pins in use, move it to
the “T” pair, and push it on.
2.
Set the humidistat high enough so that unit will remain
“on call” for at least one hour.
3.
After about 35 minutes of operation, activation will
take place, causing the drain valve to open.
The
water level will then drop to level B (see figure 8-1 on
page 8) and cause the fill valve to open. Both valves
will remain open for about 10 minutes.
4.
The drain valve will then close, and the water level
will rise to level A (see figure 8-1 on page 8), causing
the fill valve to close.
5.
Once the test cycle is complete, move the pin block
back to the desired pair of pins.
Failure to do so
will result in a drain/flush cycle every 35 minutes.
CRU
®
V Make-up Water Piping
If the water pressure is above 60 psi (414 kPa) and/or
water hammer would be objectionable, a pressure-
reducing valve or shock arrester should be installed.
Even though the humidifier has an internal 1" (25 mm) air
gap, some local codes may require a vacuum breaker.
Important:
Minimum water supply pressure is 25 psi (170
kPa). Maximum water supply pressure is 80 psi (552 kPa).
CRUV-DI Water Level Control System
The basic float valve water level system and float switch
circuit for heater protection in the event of a low-water
condition is common to all DI humidifiers and can be
found in the wiring diagram shipped with the unit.
CRUV-DI Start-Up Procedure
a)
Adjust humidistat to "call" setting.
b)
Open shut-off valve on water supply line. Unit should
begin filling with water through the fill valve.
c)
Shortly before the fill valve shuts off, the float
operated heater cut-off switch will "make." When
this switch makes, the heating element contactor(s)
will be actuated. A time delay relay circuit prevents
contactor chatter due to bouncing of heater cut-off
float.
d)
Check heater cut-off circuit.
1.
Close manual valve on water supply.
2.
Open drain valve and start draining unit.
3.
When water level drops past switching level on
the heater cut-off float, the heating element
contactor(s) will drop out.
4.
When step 3 has been satisfactorily completed,
close drain valve.
