MELBURY HE 3800-10000 -
Installation, Use and Maintenance
Page 20 / 36
410821-V11
2.6. Correction values for different operating conditions
2.6.1. Flue gas temperature correction values
Average boiler water
temperature
tm °C
50
60
70
80
90
100
Flue gas temperature
difference
∆
t K
- 16
- 8
±
0
+ 8
+ 16
+ 24
Excess air
λ
−
1.10
1.15
1.20
1.25
1.30
1.35
Flue gas temperature
difference
∆
t K
- 6
- 3
± 0
+ 3
+ 6
+ 8
2.6.2. Modulation range
In chapter 2.7 modulation ranges are indicated for an
average boiler water temperature of tm = 70°C.
Since the minimum power of the boiler is limited by
the minimum allowable flue gas temperature, the
modulation range increases when the average boiler
temperature increases. This is exemplary illustrated
in the figure below (example for oil operation with a
minimum flue temperature of 120°C).
figure 7 - Flue gas temperature – Boiler power diagram
(example for two average boiler water temperatures)
2.6.3. Stand-by loss correction values
Average temperature difference *
tm
°C
30
40
50
60
70
Stand-by loss correction
∆
qB
%
- 40
- 20
± 0
+ 20
+ 40
* Average temperature difference = Average boiler
water temperature minus ambient air temperature
Average boiler water temperature = Average of
supply and return temperature
