20
Heat-Timer Corp.
seQuence
Lo/Hi/Lo/Hi, Lo/Lo/Hi/Hi
Default: Lo/Hi/Lo/Hi
Hold Button:
MENU/<System Startup>/..../Sequencing
• Some boilers are designed to run more efficient when the lower firing stages are run
than with the higher stages. These types of boilers should select Lo/Lo/Hi/Hi. Then, the
SQ-Elite-MV will sequence the lower stages of all boilers with Modes configured as Auto
before sequencing the higher stages.
------ SEQUENCE -------
Lo/Hi/Lo/Hi
Lo/Lo/Hi/Hi
BACK SAVE
• For the rest of the boiler types, the Lo/Hi/Lo/Hi should start the firing of the lower stage of the lead boiler followed by the higher
stage of the same boiler. Then when more stages are needed, it will fire the lower stage of the lag boiler followed by the higher
stage of the lag boiler.
control logIc
PID, OSS (Over-Sized-System)
Default: PID
Hold Button:
MENU/<System Startup>/..../Control Logic
• The PID option allows the SQ-Elite-MV to sequence stages based on Reaction Time and
Boiler Min Run Time. The PID relies on the rate of change in the SEQ system temperature.
The PID logarithmic calculations foresee changes and sequence stages based on those
changes. It is the most efficient operation for most heating applications. See page
--- CONTROL LOGIC---
PID
OSS
BACK SAVE
• The Oversize option sequence stages based on how many Throttling ranges (differentials) is the SEQ system temperature away
from the SEQ Target temperature. At one Throttling range below the SEQ Set Point, only one stage will be on. For each additional
Throttling range below the SEQ Set Point, an additional stage will be activated. The last stage on will be allowed to exceed the
SEQ Set Point by one Throttling range before turning off. This helps prevent the last stage from short cycling. See Throttle on
When PID is Selected, the following are the settings that directly affects this modes operation:
• Reaction Time
Hold Button:
MENU/SEQ Settings/System Settings/Stage Settings/Reaction Time
• Purge Delay
Hold Button:
MENU/SEQ Settings/System Settings/Stage Settings/Purge Delay
• Minimum Run Time
Hold Button:
MENU/SEQ Settings/System Settings/Stage Settings/Min Runtime
• Standby Delay
Hold Button:
MENU/SEQ Settings/System Settings/Stage Settings/Standby Delay
• Last Stage Hold
Hold Button:
MENU/SEQ Settings/System Settings/Stage Settings/Last Stage Hold
When Oversize (OSS) is Selected, the following are the settings that directly affects this modes operation:
• Throttle
Hold Button:
MENU/SEQ Settings/System Settings/Stage Settings/Throttle
seQ sensor fault
Stages On, Stages Off
Default: Stages On
Hold Button:
MENU/<System Startup>/..../SEQ Sensor Fault
The SEQ Sensor Fault will determine the operating status of all output stages that are set to
Auto when a sensor reads Short or Open.
SEQ SENSOR FAULT
Stages On
Stages Off
BACK SAVE
reset Mode
• When Stages-On is selected, the SQ-Elite-MV will turn all boiler stages On when the SEQ System reads Short or Open and the
outdoor temperature is below SEQ Outdoor Cutoff. However, if the outdoor temperature is above the Outdoor Cutoff, the Outdoor
Cutoff will take over turn off the stages. When the outdoor reads Short or Open, the SQ-Elite-MV will change the Target to the
Maximum Target.
• When Stages-Off is selected, the SQ-Elite-MV will turn all stages Off when the SEQ System reads Short or Open. However, when
the Outdoor reads Short or Open, the SQ-Elite-MV will change the Target to the Minimum Target.
set poInt Mode
• When Stages-On is selected, the SQ-Elite-MV will turn all stages On when the SEQ System sensor reads Short or Open.
• When Stages-Off is selected, the SQ-Elite-MV will turn all stages Off when the SEQ System sensor reads Short or Open.
• The Outdoor Sensor Short or Open status will not affect the control operation in Set Point mode.
