Reset Ratio; Target Offset; Minimum Target - heat-timer Multi-MOD Platinum Installation And Operation Manual

ReSeT RATIO

Adjustable from 1.00ºOD:4.00ºSys to 4.00ºOD:1.00ºSys
PReSS TO SeleCT: /<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 floor heating applications .
• With most baseboard heating applications, a 1 .00 (OD):1 .00 (SYS)
setting is a good place to start .
• If required: Adjust the Reset Ratio in cold weather . 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 .

TARGeT OFFSeT

Adjustable from +40Fº/+22Cº to (-40Fº/-22Cº)
PReSS TO SeleCT: /<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: Adjust the Water Offset in mild weather . 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 .

MINIMuM TARGeT

Adjustable from 70ºF/21ºC to 170ºF/77ºC
PReSS TO SeleCT: /<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 specification .
Multi-MOD Platinum with Space and Scheduling Installation and Operation Manual
Default: 1.00ºOD:1.00ºSys
Default: 0Fº/0Cº
Default: 70ºF/21ºC
---- 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
1:4 1:3 1:2
220
210
200
190
180
170
160
150
140
130
120
110
100
70 60 50 40 30 20 10 0
Outdoor Temperature (in °F)
Reset Ratio (Outdoor : Water)
Reset Ratio Curves
------- OFFSET -------
0 F
+
[
Offset=10°F Min Target=120°F
Reset Ratio=1.5 : 1.0 Max Target=170°F
180
170
Max Target
160
150
140
130
120 Min Target
110
100
70 60 50 40 30 20 10
Outdoor Temperature (in °F)
Target Offset
-- MINIMUM TARGET --
80 F
[
1:1.5
1:1.25
1:1
1.25:1
1.5:1
2:1
3:1
4:1
-10 -20
]
0 -10 -20
]
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