heat-timer Mini-MOD-CNC Installation And Operation Manual page 22

SWITCH SET POINT
Adjustable from 0ºF/–18ºC to 200ºF/94ºC
Button: MENU/<System Startup>/.../Sensor Type/Switch Setpoint
• It is the Target Temperature Set Point at which the Mini-MOD-CNC will switch between
Condensing Boiler Group and Non-Condensing Boiler Group.
• The Condensing Boiler Group will be the lead group when the Target Temperature is
below the Switch Set Point. However, the Non-Condensing Group will be the lead group
when the Target Temperature is above the Switch Set Point.
SWITCH DIFFERENTIAL
Adjustable from 5Fº / 3Cº to 20Fº / 11Cº
Button: MENU/<System Startup>/.../Switch Setpoint/Switch Diff
• The Switch Differential controls the group switching. It allows the Target Temperature to
drop a specified number of degrees below the Switch Set Point before changing the lead
group over.
• The Switch Differential should be set to a high setting to reduce the switching frequency
between the Condensing and Non-Condensing Boiler Groups, particularly if no Switch
Delay was set. See next setting.
SWITCH DELAY
Adjustable from 0.0 to 12.0 Hours
Button: MENU/<System Startup>/.../Switch Setpoint/Switch Diff/Switch Delay
• The Switch Delay is an additional layer of assurance used to reduce the intermittent
change of the lead group.
• To switch the lead group when the temperature is dropping, the Target Temperature
must drop below the Switch Set Point less the Switch Differential and remain below the
Switch Set Point for the complete Switch Delay period before the switching of the lead
group could take effect. That is, if the Switch Set Point was set to 135ºF, and the Switch
Differential was set to 5Fº, then the Target Temperature must drop below 130ºF for the
complete Switch Delay for the lead group to change from condensing to non-condensing.
• To switch the lead group when the Target Temperature is rising, the Target Temperature
must rise above the Switch Set Point for the complete Switch Delay before the switching
of the lead group could take effect.
• Note that if the Switch Delay was set to 0.0 hours, the Mini-MOD-CNC will utilize it built-in
delays. These delays vary between 3 to 15 minutes based on the Boiler Types used.
HEAVY LOAD SEQUENCE 2ND GROUP
Yes, No
Button: MENU/<System Startup>/.../Switch Delay/Heavy Load Seq#2 Group
• This option makes the second group of boilers act as a backup in heavy load conditions.
Thus, allowing them to start after all lead group boilers have run at their maximum
capacity.
• If the system was designed to operate both groups of boilers in heavy load conditions,
then select Yes.
• Selecting No will only allow the lead group to operate. The secondary group will remain
off even if the system cannot reach the desired set point.
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22 HEAT-TIMER CORP.
Default: 150ºF/ 66ºC
Default: 5Fº / 3Cº
Default: 0.5 hours
Default: Yes
10 STARTUP MENU SEQUENCE
SWITCH SETPOINT
150°F
BACK
SWITCH DIFF
5°F
BACK
SWITCH DELAY
0.5 hour
BACK
HEAVY LOAD
SEQUENCE #2 GROUP
No
Yes
BACK
059102-00 REV. C
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SAVE
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