Reset Ratio/Outdoor Reset - Raypak TempTracker mod+ Installation And Operation Instructions Manual

understandInG operatIon concept
The TempTracker mod+ has multiple operating modes that satisfy most hydronic systems.
It can change the System Set Point based on outdoor temperature (Outdoor Reset) or it can
modulate its stages to achieve an adjustable fixed Set Point.
In Outdoor Reset, the TempTracker mod+ controls a hot water heating system to provide a
building with comfortable and even heat levels. The TempTracker mod+ varies the temperature
of the circulating heating water in response to changes in the outdoor temperature. The heating
water temperature is controlled through the modulation of stages.
The TempTracker mod+ also controls the system circulating pump with an adjustable Outdoor
Cutoff. When the outdoor temperature is above Outdoor Cutoff, the pump is off and no heating
water is circulated through the system. When the outdoor temperature drops below the Outdoor
Cutoff, the system pump relay is activated and the heating water circulates through the system.
The temperature of the heating water is controlled by the Reset Ratio, Water Offset, and changes
with Outdoor temperature.

reset ratIo/outdoor reset

When a building is being heated, heat escapes through the walls, doors, and windows to
the colder outside air. The colder the outside temperature, the more heat escapes. If you
can input heat into the building at the same rate that it is lost out of the building, then
the building temperatures will remain constant. The Reset Ratio is an adjustment that
lets you achieve this equilibrium between heat input and heat loss.
The starting point for most systems is the 1.00 (OD):1.00 (SYS) (Outdoor Air
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 curves is adjustable, but comes factory selected at
70 F Outdoor Temp. and 100
°
ratio, if the outdoor temperature is 40
the starting point of 70 F. Therefore, the heating water temperature will increase 30
°
130 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 the outdoor temperature would have to drop
2 degrees 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 dropped the water
temperature will increase 2 degrees. The TempTracker mod+ 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 heat comfort. The following are suggested initial settings for different
types of radiation based on average building insulation and heat loss. The contractor
can fine tune these adjustments based on the specific building need.
type of radiation in building
Radiators (Steel & Cast Iron)
Baseboard (Finned copper tube& Cast Iron)
Radiant (High Mass/Concrete)
Radiant (Low Mass/Joists)
Fan Coils & Air Handlers
TempTracker mod+ & TempTracker mod+ Extension Installation Manual
F Water Temp. For example with a 1.00 (OD):1.00 (SYS)
°
F, this means the temperature has fallen 30
°
1.00 (OD) : 1.00 (SYS)
1.00 (OD) : 1.00 (SYS)
4.00 (OD) : 1.00 (SYS)
2.00 (OD) : 1.00 (SYS)
1.00 (OD) : 1.00 (SYS)
1:4
130
Warmer
120
110
100
70 60 50
reset ratio offset
Outdoor Temperature
0˚F
0˚F
-10˚F
-10˚F
20˚F
220
210
200
190
180
170
160
150
140
130
120
110
100
70 60
Outdoor Temperature (in °F)
Reset Ratio is Presented as
Outdoor Temp. : Water Temp. Ratio
Reset Ratio Curves
With a 0° Offset, the
Reset curves begin at
100° Water Temperature.
With a -20° Offset, the
Reset curves begin at
from
°
80° Water Temperature.
to
°
With a +20° Offset, the
Reset curves begin at
120° Water Temperature.
1:1
Colder
4:1
40
WarnInG
When controlling a non 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.
5
1:4 1:3 1:2 1:1.5
1:1.25
1:1
1.25:1
1.5:1
2:1
3:1
4:1
50 30 0 -10
40 20 10 -20
1:4 1:1
130
120
110
4:1
100
70 60 50 40
Outdoor Temperature
1:4 1:1
110
100
90
-20 Offset
4:1
80
70 60 50 40
Outdoor Temperature
1:4 1:1
150
140
130
4:1
120
90
+20 Offset
100
70 60 50 40
Outdoor Temperature