LAARS M4-Ext - Installation Manual - Manual (Page 19)

Installation Manual 19
SEqUENCiNg BOiLER SETTiNgS
SEqUENCiNg OUTPUT TYPE
On/Off, 2-Stage, 3-Stage, 4-Stage Outputs Default: On/Off
• The M4-CNC can sequence any type of multi-stage boiler starting with a single On/Off and
up to a 4-stages. Just select the number of stages per boiler from this menu option.
• The number selected applies to all sequencing boilers within that group whether it is
condensing or non-condensing.
NON-CONDENSING
-- OUTPUT TYPE --
On/Off
2-Stage
3-Stage
4-Stage
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STAgiNg MOdE
Lo/Hi/Lo/Hi, Lo/Lo/Hi/Hi Default: Lo/Hi/Lo/Hi
• During low load conditions, some boilers run more efficient when the lower stages are
energized alone than with the higher stages. For these types of boilers select Lo/Lo/Hi/Hi.
Then, the M4-CNC will sequence the lower stages of all boilers their Mode is set to Auto
before sequencing the higher stages.
• For the rest of the boiler types, the Lo/Hi/Lo/Hi should allow the staging 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.
NON-CONDENSING
- STAGING MODE -
LO/HI/LO/HI
LO/LO/HI/HI
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PROvE/dOMESTiC HOT WATER (dHW) PRiORiTY
Prove, DHW Priority, DHW No Priority, No Priority (Summer) Default: Prove
Button: MENU/<System Startup>/..../Prove-DHW Sharing
• This setting determines the functionality of Input Terminals 29 and 30.
• When Prove is selected, the M4-CNC will not start any boiler unless Prove terminals are
shorted/closed. However, it will allow the System relay to function normally.
PROVE/DHW SHARING
Prove
DHW Priority
DHW No Priority
No Priority (Summer)
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• Using the terminals to connect to an aquastat for a Domestic Hot Water call and selecting any of the DHW options will raise the
calculated water temperature to the DHW Set Point (See next setting).
• The Domestic Hot Water Priority option de-energizes the System relay during domestic hot water calls for a period of one hour.
If after the priority period the DHW call did not expire, the System relay will energize providing heat to the building and the
temperature target will remain at the DHW Set Point. After the DHW call ends, the set point will drop to satisfy the reset ratio or
set point.
• Domestic Hot Water No Priority option allows the System relay to remain energized during a domestic hot water call (aquastat call
on terminals 29 and 30). However, in Summer, Shutdown, No Tstat call for heat, or when outdoor temperature is above Outdoor
Cutoff, a DHW call will energize the System relay. After the DHW call terminates, the System relay will continue to run for the
System Run-On period before turning off.
• Domestic Hot Water No Priority (Summer) behaves the same as the DHW No Priority. The only difference is that in Summer,
Shutdown, No Tstat call for heat, or when outdoor temperature is above Outdoor Cutoff, a DHW call WILL NOT energize the
System relay except for the Run-On delay after the DHW call ends.
dOMESTiC HOT WATER SET POiNT
(AvAiLABLE wiTH Any of THE DHw PRioRiTy oPTionS)
Adjustable from 140ºF/ 60ºC to 200ºF/ 93ºC Default: 180ºF/ 82ºC
Button: MENU/<System Startup>/..../DHW Set Point
• On a DHW call, the M4-CNC will raise the target to the DHW Set Point until the DHW call
expires.
- DHW SETPOINT -
180 o F
[ ]
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SHUTdOWN/TSTAT/SETBACk MOdE
Shutdown Input, Tstate Input, Setback Input Default: Shutdown Input
Button: MENU/<System Startup>/..../Setback\Shutdown
• The M4-CNC has two levels of heat, a Normal/Day and a Setback/Night. The Normal/Day
is good for when buildings are occupied and people are active. The Setback/Night holds a
lower system temperature for night periods or when buildings are unoccupied.
- SETBCK/SHUTDOWN -
Shutdown/Disable
Tstat/Enable
Setback
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LAARS Modulating Controls M4 & M4-EXT
HT# 059104-00 B