heat-timer Multi-MOD Platinum - RESET RATIO; TARGET OFFSET; MINIMUM TARGET

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HT# 059299-00 A
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 /<System Settings>/ Reset Ratio
• The Reset Ratio adjusts the system target temperature based on the
outdoor temperature See "Suggested Reset Settings" on page 6
• It uses a system water temperature of 100°F and an outdoor temperature
of 70°F as the reset ratio beginning point With a 100 (OD):400 (Sys)
ratio, the System water temperature (Sys) will increase rapidly as the
outside temperature falls, hitting 220°F at 40°F outside temperature
With a 400 (OD):100 (SYS) ratio, the System temperature (SYS) will
increase slowly as the outside temperature falls Even at -10°F outdoor
temperature, the system water will only be 120°F Such a low Reset
Ratio might be used with radiant oor heating applications
• With most baseboard heating applications, a 100 (OD):100 (SYS)
setting is a good place to start
• If required:  If the ambient
building temperature is cold, move the ratio to a higher selection That
is, if 100 (OD):100 (SYS) was initially selected, change the selection to
100 (OD):125 (SYS) If the building temperature is too warm, move the
ratio to a lower selection That is, if 100 (OD):100 (SYS) was initially
selected, change it to 125 (OD):100 (SYS)
• After changing the Reset Ratio, wait at least 24 hours before making any
additional adjustments
---- RESET RATIO ----
1.00 OD=4.00 Sys
1.00 OD=3.00 Sys
1.00 OD=2.00 Sys
1.00 OD=1.50 Sys
1.00 OD=1.25 Sys
1.00 OD=1.00 Sys
1.25 OD=1.00 Sys
1.50 OD=1.00 Sys
2.00 OD=1.00 Sys
3.00 OD=1.00 Sys
4.00 OD=1.00 Sys
Reset Ratio (Outdoor : Water)
70 60 50 40 2030 0 -1010 -20
100
120
110
130
140
150
160
180
170
190
200
210
220
Water Temperature (in °F)
Reset Ratio Curves
Outdoor Temperature (in °F)
1:1.25
1:1
1.25:1
1.5:1
2:1
3:1
4:1
1:4 1:3 1:2 1:1.5
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 /<System Settings>/ Reset Ratio
• The Offset setting moves the Reset Ratio curve vertically This means
that, regardless of the outdoor temperature, or the Reset Ratio selected,
when the Offset setting is changed, that change is directly added to or
subtracted from the calculated temperature For example, if the target
temperature was 130°F and the Offset was changed from 0° to 10° (an
increase of 10°), the Set Point would increase to 140°F
• If required:  If the ambient
building temperatures are too warm in the mild weather, decrease the
Offset If the ambient building temperatures are too cold in the mild
weather, increase the Offset
• The rule of thumb for baseboard radiation is to change the Offset 4°F for
every 1°F you wish to change the building temperatures
• In radiant heat applications, change the Offset 1°F or 2°F for every 1°F
you wish to change the building temperature
------- OFFSET -------
+0 F
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Outdoor Temperature (in °F)
70 60 50 40 2030 0 -1010 -20
120
140
130
150
160
170
180
100
110
Water Temperature (in °F)
Target Offset
Offset=10°F
Reset Ratio=1.5 : 1.0
Reset Ratio
Max Target
Min Target
Reset Ratio + 10F Offset
Min Target=120°F
Max Target=170°F
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 
 /<System Settings>/<More Settings>/Min Water Temp
• The Minimum Target temperature is the lowest temperature the control
will use as a target Primarily, it is used to protect non-condensing boilers
from extended periods of low temperature
• This value must be set to the boiler manufacturer’s specication
-- MINIMUM TARGET --
80
F
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