Space Feedback Concept - heat-timer Multi-MOD Platinum Installation And Operation Manual

The starting reset ratio for most systems is the 1 .00 (OD):1 .00
(SYS) (Outdoor Temperature : Heating Water Temperature) ratio .
This means that for every degree the outdoor temperature drops,
the temperature of the heating water will increase one degree .
The starting point of the ratio is adjustable, but comes factory
set to 70°F Outdoor Temperature and 100°F Water Temperature .
For example with a 1 .00 (OD):1 .00 (SYS) ratio, if the outdoor
temperature is 50°F, this means that the outdoor temperature has
fallen 20° from the starting point of 70°F . Therefore, the heating
water temperature will increase 20° to 120°F (100°F + 20°F) .
Each building has different heat loss characteristics . A very well
insulated building will not lose much heat to the outside air, and
may need a Reset Ratio of 2 .00 (OD):1 .00 (SYS) (Outdoor :
Water) . This means that the outdoor temperature would have
to drop 2° to increase the water temperature 1 degree . On the
other hand, a poorly insulated building with insufficient radiation
may need a Reset Ratio of 1 .00 (OD):2 .00 (SYS) . This means
that for each degree the outdoor temperature drops the water
temperature will increase 2° . The Multi-MOD Platinum has
a full range of Reset Ratios to match any buildings heat loss
characteristics .
A heating curve that relies not only on Outdoor temperature but
also on type of radiation will improve the comfort . See the Building
Suggested Settings table for different types of radiation based on
an average building insulation and heat loss . The contractor can
fine-tune these settings to the specific building need .

SPACe FeeDBACk CONCePT

A Multi-MOD Platinum control that is equipped with Internet
communication is capable of using Heat-Timer space sensors to
fine-tune its outdoor reset operation while providing significant
savings . The Multi-MOD Platinum adjusts the target water
temperature based on the Space Feedback Gain and the
difference between the current Space Average and the Space
target . Example: Using a Space Feedback Gain of 4, if the
Space Average is 70°F and the day target is set to 72°F, the
control will add 4° to the System Target temperature for every 1°
(ambient temperature) the Space Average is below the Space
Target . In this example, it would add 8° to the target water
temperature to compensate for the 2° reduction in the Space
Average . See "Space Feedback Gain" on page 47 .
If the Space temperature exceeded the Space Target by 2°
while the target water temperature is at the Minimum Target
temperature for an hour, the control will turn the boilers off until
the Space Average drops below the Space Target .
6
Multi-MOD Platinum with Space and Scheduling Installation and Operation Manual
WARNING
When controlling a none-condensing
boiler directly without the use of a
mixing valve, minimum boiler water
temperature must be set to boiler
manufacturer specifications . In that
case, system temperature must not go
below such temperature .
Suggested Reset Settings
Transfer unit
Radiators (Steel & Cast
Iron)
Baseboard (Finned copper
tube& Cast Iron)
Radiant (High Mass/
Concrete)
Radiant (Low Mass/Joists)
Fan Coils & Air Handlers
Reset Ratio Offset
1 .00 : 1 .00 0˚F
1 .00 : 1 .00 0˚F
4 .00 : 1 .00 -10˚F
2 .00 : 1 .00 -10˚F
1 .00 : 1 .00 20˚F