Hamworthy Weymouth Advanced, Инструкция по установке, наладке и обслуживанию

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HAMWORTHY HEATING LTD
20
WEYMOUTH 500001112/C
Figure A2 - Heating System Calculation Sheet
1. System Parameters
System Water Content - Vs = litres
System Anti-freeze Content - ra = %
Maximum System Working Pressure - P
w
= bar
Maximum Static Head -
P
h
= metres
If the system volume is not known then the following rule of thumb can be applied:
System water content = Boiler power (KW) X 10
2. Expansion Vessel Volume Calculation, Vv-
(ra + 81.5) x Vs ( + 81.5 ) x
Vv = = Vv = litres
921 921
If the system is to be set up using the factory preset pressure switch levels for the Weymouth unit then
no other calculations are necessary. The factory preset switch levels are:
Cold Fill Pressure Switching Level, P
f
= 1.8 bar
Hi Pressure Switching Level, P
hi
= 3.65 bar
Lo Pressure Switching Level, P
lo
= 1.5 bar
The safety valve lift pressure should be set 0.35 bar above the Hi pressure switching level.
3. Cold Fill Pressure Switch Setting Calculation, P
f
-
P
h
P
f
= + 0.2 = + 0.2 P
f
= bar
10.2 10.2
4. Safety Valve Lift Pressure Calculation, P
s
-
Actual fitted expansion vessel volume, V
va
- V
va
= litres
Actual fitted expansion vessel acceptance factor, a
va
-
V
v
x 0.35 x 0.35
a
va
= = a
va
=
V
va
Actual working pressure, P
wa
-
P
f
+ a
va
+
P
wa
= = P
wa
= bar
1 - a
va
1 -
Note! If P
wa
> P
wa
then increase expansion vessel volume, V
va
and recalculate from step start of step 3
P
s
= P
wa
+ 0.7 = + 0.7 P
s
= bar
5. Calculation of Expansion Vessel Acceptance Factor at Safety Valve Lift Pressure, a
s
-
P
s
- P
f
-
a
s
= = a
s
=
P
s
- 1 - 1
Note! If a
s
> 0.5 then increase expansion vessel volume, V
va
and recalculate from step start of step 3
6. Lo Pressure Switch Setting Calculation, P
sl
-
P
sl
= P
f
- 0.3 = - 0.3 P
sl
= bar
7. Hi Pressure Switch Setting Calculation, P
si -
P
sh
= P
wa
- 0.35 = - 0.35 P
sh
= bar
Example
Vs = 2000 litres
ra = 10%
P
w
= 8 bar
P
h
= 22 m
( 10+81.5) x 2000
Vv = = 199
921
22
P
f
= + 0.2 = 2.35
10.2
V
va
= 300
a
va
= 0.23
2.35 + 0.23
P
wa
= = 3.35
1 - 0.23
P
s
= 3.35 + 0.7 = 4.05
4.05 - 2.35
a
s
= = 0.56
4.05 - 1
P
sl
= 2.05
P
wa
= 3.0