How The Humidifier Works - Honeywell HM700A1000 Instructions D'installation

How the Humidifier Works

The HM700 is an atmospheric steam generator that uses heat
generated by electrical current flowing between submerged
electrodes to generate steam. The HM700 is designed for on-
demand air humidification via a steam distributor.
STEAM GENERATION
• Once the unit receives a demand signal and the safety loop
between terminal 1 and 2 is closed, the humidifier closes
the contactor and measures the electrical current.
• If the demand is lower than the actual output the inlet valve
is kept closed and output is reduced by letting the water
level in the cylinder decrease by evaporation.
• If demand is higher than the actual output, after a brief
delay the fill valve is activated and water flows into the fill
cup. Water from the fill cup flows into the bottom of the
cylinder through a hose connected to the drain valve
housing.
NOTE: The cylinder is gravity fed from the fill cup. If
backpressure from the steam line is too high it
will cause water to back up in the fill cup and
flow down the overflow line to the drain.
• As soon as the water in the cylinder comes in contact with
the energized electrodes, current flows through the water.
The resistance of the water to the electrical charge
generates heat and in turn steam. The electrical current
(and steam output) increases as the level of water
increases, as more of the electrode becomes submerged.
The unit continues to fill until the current matches demand
or the high water sensor detects a high water level.
• The HM700 repeats the fill and boil down cycle repeatedly
to match output to demand.
• Over time minerals in the water will adhere to the cylinder
electrodes. The humidifier will automatically fill to a higher
water level to maintain full capacity during the life of the
cylinder. Eventually because of scale formation it will no
longer be possible for the humidifier to reach its full
capacity. The HM700 software monitors this condition and,
when detected, will stop operating and flash the yellow
LED in a repeating sequence of 4 flashes.
DRAINS
• As steam is produced, minerals are left behind, increasing
the conductivity of the water. The HM700 patented auto
adaptive cycle will monitor the water conductivity and
perform drains to maintain the water at optimal conductivity
for peak performance.
• The auto adaptive cycle ensures cylinder life is maximized.
It does this by keeping the tightest control and most
efficient use of water during the entire cylinder life.
STEAM DISTRIBUTION
Steam generated by the humidifier may be introduced into the
air in several different ways. The most common method for
adding the steam into the air is to mount a steam distributor
tube in a supply air duct.
STEAM LINE
The steam line between the cylinder steam outlet and the
distributor serves two purposes: it is used as a conduit to
transfer the atmospheric steam from the humidifier to the
distributor, as well as providing a means to remove
condensate. See "Steam Lines and Condensate Return
Instructions" on page 8 for information on selecting steam
lines.
CONDENSATE RETURN
Whenever steam is distributed condensate is formed in the
distribution system. Insulating steam lines is one important
way to reduce the amount of condensate formed. Steam lines
are sloped so that condensate does not collect in the lines and
create a restriction to steam flow. The condensate must be
collected and removed from the system so that it does not
build up and leak into the duct. Condensate can be returned to
the HM700 fill cup to reduce water waste or can be fed to
drain.
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HM700A1000
33-00118EFS—01