059705–00 REV. B
|
7
02
HYDRONIC HEATING
UNDERSTANDING OPERATION CONCEPT
The Genesis Heat-Timer
®
operating mode for hydronic systems will change the System
Set Point based on outdoor temperature (Outdoor Reset) as this is the most efficient
method of heating a building. The Genesis Heat-Timer
®
DOES NOT
operate as a
Setpoint controller.
In Outdoor Reset, the Genesis Heat-Timer
®
controls a hot water heating system
(boiler or 3-way mixing valve) to provide a building with comfortable/even heat levels.
The Genesis Heat-Timer
®
varies the temperature of the circulating heating water
in response to changes in the outdoor temperature and on the space temperature
feedback from building sensors.
The Genesis Heat-Timer
®
also controls the system circulating pump with an adjustable
Outdoor start. When the outdoor temperature is above Outdoor start, the pump is off
and no heating water is circulated through the system. When the outdoor temperature
drops below the Outdoor start, 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, changes with Outdoor temperature and feedback
from building space sensors.
Water Temperature
70
60
50
40
Outdoor Temperature
130
120
110
100
Water Temperature
70
60
50
40
Outdoor Temperature
110
100
90
80
Water Temperature
70
60
50
40
Outdoor Temperature
150
140
130
120
1:4
With a 0° Offset,
the Reset curves
begin at 100°
Water Temperature.
With a -20° Offset,
the Reset curves
begin at 80° Water
Temperature.
With a +20° Offset,
the Reset curves
begin at 120° Water
Temperature.
1:4
1:4
1:1
1:1
1:1
4:1
4:1
4:1
90
100
+20 Offset
-20 Offset
Outdoor Temperature
W
at
er
T
em
per
at
ur
e
70
40
50
60
130
120
110
100
1:4
1:1
4:1
Colder
Warmer
70 60 50 40 30 20 10
0 -10 -20
100
120
110
130
140
150
160
180
170
190
200
210
220
1:3
1:2
1:1.5
1:1.25
1:1
1.25:1
1.5:1
2:1
3:1
4:1
Water
Temperature (in °F)
Outdoor Temperature (in °F)
Reset Ratio is Presented as
Outdoor Temp. : Water Temp. Ratio
Reset Ratio Curves
1:4
