LAARS S8Ext - Installation Manual - Manual (Page 27)

Page 27 LAARS Sequencing Controls S8 & S8EXT
DHW SETTINGS
Button: MENU/<System Settings>/<DHW Settings>
• A DHW call can be initiated by shorting the DHW input terminals, 33 and 34. In
addition, using a Laars temperature sensor on the same terminals instead of a dry contact
input will add the DHW Set Point and Differential control capability.
• In addition to raising the Target to either 200ºF or the Maximum Target on a DHW call,
which ever is lower, the S8 provides three levels of DHW pump operation. The
-- DHW SETTINGS ---
DHW Temp. 120 F
DHW Prior Tmr 60min
DHW Set Point 120 F
DHW Diff.
5 F
BACK SELECT
first is when Primary/Secondary is selected as the DHW Piping from the Startup Menu. This option will provide no DHW
Priority. Furthermore, if there was a DHW call during the Summer or when the outdoor temperature is above the Outdoor
Cutoff, both the DHW Pump and the System relays will energize. Upon the termination of the DHW call, the DHW Pump relay
will de-energize leaving the System relay energized for the Run-On delay.
• The other two DHW options are available when Parallel is selected as the DHW Piping from the Startup Menu. These two
options will not allow the System relay to energize in the Summer or when the outdoor temperature is above the Outdoor Cutoff
on a DHW call.
• In Winter, if the DHW Priority Timer was set to NO, a DHW call will keep the System relay energized in addition to energizing
the DHW Pump relay. Upon termination of the DHW call, the DHW Pump relay will de-energize leaving the System relay on.
• In Winter, if the DHW Priority Timer was set to a value other than NO, a DHW call will de-energize the System relay and
energize the DHW Pump relay. This will remain for the period of the DHW Priority Timer setting or until the DHW call
terminates, whichever is sooner. If the DHW call was still active after the DHW Priority Timer elapses, the System relay will
energize for the remaining of the DHW call period.
DHW PRIORITY TIMER (AVAILABLE WITH PARALLEL DHW PIPING)
Adjustable NO, 1 to 120 minutes Default: NO
Button: MENU/<System Settings>/<DHW Settings>/DHW Prior. Timer in Parallel
• The DHW Priority Timer provides the user with the capability of selecting the
DHW Priority period. If NO was selected, both DHW Pump and System relay will
be energized on a DHW call whenever the control is set to Winter and the Outdoor
temperature is below or at the Outdoor Cutoff.
DHW PRIORITY TIMER
2min
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• In Summer, a DHW call will energize only the DHW Pump relay leaving the System relay de-energized.
• If the DHW Priority Timer was set to a value other than NO, a DHW call in the Winter when the Outdoor temperature is below
the Outdoor Cutoff will cause the System relay to de-energize and the DHW Pump relay to energize for the period of the DHW
Priority Timer or until the DHW call expertise, whichever happens sooner. If the DHW call did not expire within the Priority
period, then the System relay will energize.
• If there was a DHW call during Summer or when the Outdoor temperature is above the Outdoor Cutoff, only the DHW Pump
relay will energize.
DHW SET POINT (REQUIRES AN OPTIONAL DHW TEMPERATURE SENSOR)
Adjustable 100°F/38°C to 200°F/93°C Default: 160°F/71°C
Button: MENU/<System Settings>/<DHW Settings>/DHW Set Point
• This is the desired DHW temperature setting at which the DHW Pump relay will de-
energize when reached.
• The S8 can accept a DHW call in two ways. An aquastat can provide a dry contact
closure to terminals 33 and 34 is the first option.
-- DHW SET POINT --
160 F
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BACK SAVE
• The second option will be connecting a Laars temperature sensor (CA002400 or equivalent) for immersion in a 3/8ID well
(CA002500 or equivalent) will offer the capability of adjusting the DHW Set Point and Differential through he S8 easy to
follow menu. In addition to being able to view and log DHW temperature history.
DHW DIFFERENTIAL
Adjustable 5°F/3°C to 80°F/44°C Default: 10°F/6°C
Button: MENU/<System Settings>/<DHW Settings>/DHW Diff.
• This represents the number of degrees the DHW temperature can drop from the DHW
Set Point before a DHW call can be recognized and the DHW Pump relay energized.
• Larger Differential will result in larger fluctuation in DHW temperature. However,
small Differential will have a tighter control over the DHW temperature but might result
in boilers coming on frequently for short periods to satisfy the DHW Set Point and
Differential settings.
DHW DIFFERENTIAL
10 F
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