Start Up; Installation Check - Honeywell HM750 Installation Instructions Manual

START UP

Installation Check

Before turning on power to the HM750, inspect the
installation to ensure that it was carried out correctly, as
per these installation instructions.
On/Off
The HM750 is factory-configured to operate as an On/Off
humidifier. It will run when 24 VAC from one HUM terminal
is fed back into the other HUM terminal through an
On/Off humidistat.
WARNING
Personal Injury Hazard.
Damaged or improperly installed units must not be
operated. Damaged or improperly installed units
may present a danger to persons and property.
Start Up Procedure
1. Make sure the voltage selection jumper on the
main circuit board is correctly configured to match
the mains supply voltage (120 VAC or 240 VAC).
2. If a disconnect switch is installed, turn it to the "ON"
position.
3. Ensure the water supply valve is open.
4. Press the Power/Drain button on the front of the
humidifier. This will turn the device on.
• The humidifier will perform a self-diagnostic
sequence during which the LED's and internal
components will be momentarily activated. See
"LED Status Lights" on page 16 for an
explanation of the LEDs and sequences.
• If an error is detected during the self-diagnostic
sequence the humidifier will not start. The
yellow Fault LED will flash in sequence to
indicate the detected fault. See Tables 6 and 7
for information on diagnosing and correcting
faults.
• After the system test the humidifier is in normal
operation mode.
5. Check and adjust the control set point on the control
humidistat, and if applicable, the high limit
humidistat. This will enable a call for humidity.
6. If the fan enable relay on the control board is used,
the green LED will continue to flash until the air
proving closes. Once the air closes, the flashing
green LED will become solid and the humidifier will
start steam production.
7. When the external humidistat calls for humidity, and
the air proving terminals are closed, the Filling LED
on the front of the humidifier will light up, the power
relay on the control board will engage, the water fill
valve will activate (after a delay), and the cylinder will
slowly fill with water.
NOTE: While the cylinder is filling with water there
should be no water flowing down the drain. If
water is flowing down the drain it can indicate
excessive backpressure or a leaking drain valve.
See Troubleshooting.
8. It can take up to 20 minutes for the water to be
heated up by the submerged electrodes and for
steam to be produced.
NOTE: The humidifier is shipped with a salt tablet
already inserted inside the steam cylinder. The
first start-up will provide a first boil in
5-20 minutes, depending on the water supply
conductivity.
NOTE: If the humidifier is being restarted after it has
been drained, and it has already gone through
several boil down cycles, it may take a longer
period of time for the HM750 to reach full output
capacity. It may take several hours with low
conductivity water. During this time, the
humidifier will not perform any drains and the
conductivity of the water in the cylinder will
increase.
NOTE: The humidifier performs drains intermittently as
part of its normal process of optimizing the
conductivity of the water in the cylinder. During
these drains, the Drain LED will not illuminate.
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HM750A1000
33-00289—01