23
6.3.3. Steam exchanger
With regard to general maintenance operations, follow
the steps described in 6.3.1.
In order to perform maintenance work on an Air
Treatment Unit with steam heat exchanger in absolute
safety, you must make provision for the automatic shut-
off of the steam supply in the case of motor fan unit stop.
6.3.4. Direct expansion exchanger
With regard to general maintenance operations, follow
the steps described in 6.3.1.
TCF recommends you check, on at least a weekly basis,
that there are no gas leaks from the distribution heads. In
the event of gas leaks, the COOLING CHARGE would be
lost and the whole system compromised.
6.4.
HUMIDIFIER SECTIONS
An efficient humidification system has a limited life that
depends on various factors, including:
- the type of operation (expendable, with circulation, cell
block, spray nozzles, steam, compressed air)
- the total hardness of the feed water (section 4.3.1)
- the dust concentration in the treated ain i.e. the Unit's
filtration efficiency.
6.4.1. Humidification with spray nozzles
It is advisable to CHECK EVERYWEEK THAT THE SPRAY
NOZZLES FORM A REGULAR GONE-SHAPED JET.
In the case of scale you must:
- remove the malfunctioning nozzles from the distribution
ramp
- clean the nozzles on if they are damaged, replace them
with others that have the same characteristics
- restore proper working conditions prior to restarting
the humidification system.
6.4.2. Humidification with cell block
BEFORE EACH WORKING SEASON, in order to avoid
interruptions, you must visually check that the cell block
is evenly wetted; if you observe water jets on its surface
you must restore an even water flow by adjusting the
valve.
THE CELL BLOCK CANNOT BE RECONDITIONED.
When it is fouled you must replace it as follows:
- stop the electrical pump
- cut off the water feed using the relevant gate
- let the block dry completely, keeping the fan in
operation
- remove the frame housing the block by undoing the
securing screws and lift it out of the unit through the
inspection door
- extract the fouled block from the housing and replace it
with another of the same size. Take care with the
direction of fluid flow: the water which runs along the
veins of the block must intersect the air flow in reverse
current (fig. 36)
- Check the condition of the distributor tube and, if
necessary, replace it
- Restore proper operating conditions before restarting
the humidification system.
6.4.3. Humidification with circulating pump
- AT THE START OF EACH WORKING SEASON, in order to
keep the humidification system in efficient condition, you
must check that the pump is working properly. lf it is not,
remove and clean it. If the pump still does not work
properly after cleaning, you must replace it.
- Make sure that the water level inside the tank is 20-30
mm below the overflow to avoid flooding and ensure the
pump has a sufficient water head. If the pump sucks in air,
it will overheat and sustain irreparable damage. If
necessary, adjust the float to maintain the correct water
level
- To prevent flooding of the machine and the installation
room, remove any scale and sludge that might obstruct
the drain every month.
6.4.4. Ultrasonic,
steam
(submerged
electrodes),
compressed air humidifiers .
For Air Treatment Units with these types of
humidification system, consult the TECHNICAL MANUAL
supplied with the humidifier
6.4.5. Steam humidification with submerged heating
elements
In order to preserve the heating elements, maintain the
efficiency of the humidification system and prevent over-
flows and flooding of the installation site, you must
perform the following steps at least once a month:
- check that the microswitch is working properly
- remove any deposits from the elements and the tank.
