Mini-MOD & Mini-Extension Installation Manual 23
059040-00 C
lead boIler rotatIon
Adjustable Manual, Time (1 hr to 60 Days), Last-On
Default: Time (24Hours)
Button:
MENU/<System Settings>/Lead Rotation
• The Lead Boiler is the first boiler brought on when an output is needed.
• The Lead Boiler can be rotated automatically every specified time period, manually, or
based on Last-On. The automatic rotation is recommended.
• The current Lead Boiler is shown in brackets on the main display.
• Only boilers which are set to Auto Mode can be Lead. Therefore, not all the boilers may be
available when manually selecting a new Lead Boiler.
-- LEAD ROTATION --
Manual
Time
Last-On
BACK
▲
▼
SAVE
AUTO ROTATE PERIOD
24 hrs
[
]
BACK
▲
▼
SAVE
MANUAL LEAD STAGE
A
B
C
D
BACK
▲
▼
SAVE
purge delay
Adjustable from 0.0min to 10.0min
Default: 1.0min
Button:
MENU/<System Settings>/Purge Delay
• Many boilers go through a purge cycle before they are brought on line.
• When the Mini-MOD activates a boiler, it does not start to calculate its output until the
Purge Delay is over. This allows the boiler to fully come online and begin producing output.
• The Purge Delay helps prevent short cycling of any newly activated burner. Once the
burner is activated, it
MUST
run through the entire Purge Delay period.
• The minimum Purge Delay setting
MUST
be set to the time required by the boiler
manufacturer. Time entry is in 0.1 of a minute (i.e. 1.5min will equal 90 seconds.)
• The Message Display Line will display
Purge Delay
and the amount of time remaining in
the purge.
--- PURGE DELAY ---
0.0 min
[
]
BACK
▲
▼
SAVE
alert
Set Purge Delay as per boiler
manufacturer recommendation.
lag delay
Adjustable from 0min to 60min
Default: 0min
Button:
MENU/<System Settings>/Lag Delay
• The Lag Delay requires the previous stage to remain at 100% modulation for the full period
of the Lag Delay before another Stage can be activated. For example, if the Lag Delay was
set to 10 minutes, the Lead Stage would need to remain at 100% modulation for a full ten
minutes before a lag stage could be activated. The Message Display Line will display
Lag
Delay
and the remaining time.
--- LAG DELAY ---
0.0 min
[
]
BACK
▲
▼
SAVE
• Set the Lag Delay to 0 min when two or more Stages will generally be needed to hold the load.
• The Lag Delay is useful in installations where one unit should usually have enough output to hold the load unless it fails or load
conditions become extreme.
• The Lag Delay overrides the value of the Modulation Start % selected for each stage. Regardless of that setting, the previous stage
must reach 100% and stay there before the lag stage can be activated.
• The full Lag Delay must always elapse regardless of what happens to system temperature. Therefore, set the Lag Delay to 0 min if
you want smooth set point control using multiple units.
• Note that if Parallel was selected as the Modulation Mode (See "Modulating Mode" on page 18.), this value must be set to 0 minutes
to avoid having the lead boiler going to 100% modulation prior to firing the lag boiler.
