Heat Mode; Hot Start; Hydronic Heat; Sleep Function - McQuay OM 813 Operation & Maintenance Data

Heat Mode

The unit will call for heat when Tr - Ts < 0°F becomes true.

1) Hot Start:

Hot Start is possible when the control hasn't called for
heat in more than (2) hours or during power-on-reset.
During Hot Start, the user's set point is raised 4°F (Ts +
4°F). The unit will only call for heat if room temperature
differential calls for heat. The unit will continue in Hot
Start Mode until the new set point is satisfied (with a 1°F
differential) or unit has run for at least 20 minutes. After
one or both conditions are met, the set point will be reset
to the user's setting and the unit will run in regular heat
mode. Hot start is not available with the Sleep feature.
The fan will operate per the Fan Mode and Speed setting.

2) Hydronic Heat:

Hydronic Heat control is configurable in the Set up Mode
for Normally Open or Normally Closed valve control. The
heat valve opens when the room temperature is 0°F below
set point. The heat valve closes when the room temperature
is 3°F greater than the thermostat setting.
a) Hot Keep:
When the water valve closes, the indoor fan will
operate per the user mode (Constant or Cycle) and
speed setting.
b) Heat Fan Lockout (HFLO):
Heat Fan Lockout will turn off the indoor fan if the
HFLO sensor is open (does not sense hot water or
steam) for two (2) seconds. The fan will restart when
the sensor closes.

3) Sleep Function:

Sleep time is user adjustable from 1 to 15 hours in one
hour increments, in a closed loop via the touch pad, by
pressing the Sleep button repeatedly. The Sleep Mode
can be terminated by pressing the On/Off button.
The Sleep Function will lower the temperature setting with
time. Changing the Mode or a changeover from Heat to
Cool will reset the Sleep Timer.
The Sleep function will be deactivated by Power-on-reset,
or by pressing any button on the Touch Pad except Sleep.

4) Fan Mode

In the Fan Mode, the fan will operate continuously at the
user's speed setting. The compressor and outdoor fan
will not operate. In single motor units, the outdoor fan
will run along with the indoor fan.

Set Up Mode

To enter the Set Up Mode, simultaneously press the Mode Up
and Down buttons for 5 seconds. To change settings, press
the Up or Down button. To move from one screen to another,
press the Mode button.
To exit Set Up, press the Mode Up and Down buttons
simultaneously for 5 seconds or control will automatically exit
Set Up in 15 seconds.
OM 813
Settings within the Set Up Mode are as follows:
Certified Drawing

Control Selection:

To view the Control Selection Screen, press and hold the Up
and Down buttons for 5 seconds. The setting may be changed
by pressing either the Up or Down button. The "tP" setting is
the default setting and indicates the touch pad control.

Temperature Limit Settings

To advance from Control Selection to Temperature Limit
Settings, press the Mode button once. To set the Cool
Minimum set point, press and hold Fan Cycle button and adjust
the setting with the Up or Down buttons. The minimum
setting is 60°F.
To set the Heat Maximum set point, press and hold Fan Speed
button and adjust the setting with the Up or Down buttons.
Maximum setting is 85°F.
The Display will show the upper operating limits first. The
default settings are Cool min. = 60°F and Heat max. = 85°F.

Hydronic Valve Operation

To advance from Temperature Limit Settings to Hydronic Valve
operation, press the Mode button once. To toggle the setting,
press either the Up or Down button. Settings are "no" (normally
open) and "nc" (normally closed). Default setting is "no".
Figure 8. Indoor Air and Indoor Coil Sensor Locations

Indoor Air Sensor Reading

To advance from Hydronic Valve operation to Indoor Air Sensor
Reading, press the Mode Button once. The control readout
will show room temperature.
Figure 9. Outdoor Air Sensor Location
Outdoor Air Sensor (OAS)
PTAC Digital Controls
Indoor
Coil Sensor
(ICS)
Indoor
Air Sensor
(IAS)
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