Staged Heating And Cooling Parameters - KMC Controls FlexStat Application Manual

• With the fan mode set to "Auto," the heating valve will open
100% if the space temperature falls below active heating setpoint
minus deadband and fully close when space temp rises above
active heating setpoint. The cooling valve similarly opens 100%
if the space temp rises above the active cooling setpoint plus
deadband and fully closes if the space temp falls below the active
cooling setpoint.
If at any time there is a low limit alarm, the cooling valve is forced
closed and the heating valve opens fully.
If at any time there is a fan failure alarm, the cooling and heating
valves are both forced closed.

Staged Heating and Cooling Parameters

On applications with staged heating and cooling, there will be a 3 min-
ute (adjustable) delay between calls for stages (stage delay). Once a stage
of heating or cooling turns off, there is a 3 minute (adjustable) minimum
off time before that stage's output can be reenergized. Once all stages of
heating and cooling have turned off, the fan will remain energized for 3
minutes (adjustable, off delay).
One Heating Stage
If the space temperature drops below the active heating setpoint minus
the deadband AND the first stage of heating has been off for at least the
minimum off time, the first stage of heating will be energized. Upon rise
in temperature above the active heating setpoint, the first stage of heat-
ing will be deenergized.
Two Heating Stages
If the space temperature drops below the active heating setpoint minus
one half the deadband AND the first stage of heating has been off for at
least the minimum off time, the first stage of heating will be energized.
If the space temp further drops below the active heating setpoint minus
the deadband AND the first stage of heating has been energized for at
least the stage delay AND the second stage of heating has been off for
at least the minimum off time, the second stage of heating will be ener-
gized. Upon rise in temperature above the active heating setpoint minus
one half the deadband, the second stage of heating will be deenergized.
BAC-1xx36/1xxx36 Series (3 Relays and 6 Analog Outputs) Section
Upon further rise in temperature above the active heating setpoint, the
first stage of heating will be deenergized.
Staged Cooling
If the economizer option is set to modulating economizer and the econo-
mizer mode is enabled, the stage(s) of cooling will be held off until the
outside air damper is 100% open. When the outside air damper is fully
open, normal staging of cooling is allowed. If the economizer option is
set to "Econ Dis/En" and the economizer mode is enabled, cooling is al-
lowed to stage normally.
If at any time there is a fan failure alarm or a low limit alarm, all stages
of heating and cooling are stopped at priority 5 bypassing any mini-
mum on times (minimum on times added by others, not part of the base
sequence).
One Cooling Stage
If the space temp rises above the active cooling setpoint plus the dead-
band AND the first stage of cooling has been off for at least the mini-
mum off time, the first stage of cooling will be energized. Upon decrease
in space temp below the active cooling setpoint, the first stage of cooing
shall be deenergized.
Two Cooling Stages
If the space temp rises above the active cooling setpoint plus one half
the deadband AND the first stage of cooling has been off for at least
the minimum off time, the first stage of cooling will be energized. If the
space temp further rises above the active cooling setpoint plus the dead-
band AND the first stage of cooling has been energized for at least the
stage delay AND the second stage of cooling has been off for at least the
minimum off time, the second stage of cooling will be energized. Upon
decrease in space temp below the active cooling setpoint plus one half
the deadband, the second stage of cooling shall be deenergized. Upon
further decrease in space temp below the active cooling setpoint, the first
stage of cooing shall be deenergized.
If at any time there is a low limit or fan fail alarm, all stages of cooling
and heating are deenergized.
51 Application Guide L