LAARS M4-LHS - Installation Manual - Manual (Page 24)

HT# 059295-00
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M4-LHS installation and Operation Manual
STarTuP SETTiNgS (CONTiNuED)
Prove/indirect 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-LHS will not start any boiler unless the Prove terminals are
shorted/closed. However, it will allow the System relay to operate normally.
PROVE/DHW SHARING
Prove
DHW Priority
DHW No Priority
No Priority (Summer)
BACK ▲ ▼ SAVE
• There are three DHW Priority options. In all the options, a DHW call 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 the 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.
indirect Domestic Hot Water Set Point
(Available with any of the DHW Priority options)
Adjustable from 140°F/60°C to 200°F/93°C Default: 180°F/82°C
Button: MENU/<System Startup>/..../Prove-Setpoint
• On a DHW call, the M4-LHS will raise the target temperature to the DHW Set Point until
the DHW call expires.
- DHW SETPOINT -
180 o F
[ ]
BACK ▲ ▼ SAVE
Shutdown/Tstat/Setback Mode
Shutdown Input, Tstate Input, Setback Input Default: Shutdown Input
Button: MENU/<System Startup>/..../Setback\Shutdown
• This menu determines the functionality of terminals 31 and 32.
• The M4-LHS 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
BACK ▲ ▼ SAVE
• When Shutdown or Tstat is selected, the Day/Night Schedules will be available in the
operating menu. See next settings. Terminals 31 and 32 will function as a Shutdown (Turn
off boilers when shorted) or as a Tstat (Turn off boilers when opened). However, a call for
indirect DHW will bring the boilers on.
• When Setback is selected, the External Signal option will switch the M4-LHS to Setback
mode when terminals 31 and 32 are shorted. This allows an external device or control to
provide the setback signal. No scheduling or boost menu options will be available with
Setback.