Diaphragm Expansion Vessel - Buderus Logamax plus GB162 Technical Manual

6.2.5

Diaphragm expansion vessel

In accordance with DIN-EN 12828, hot water heating
systems must be equipped with a diaphragm expansion
vessel (MAG). The equipment options with a diaphragm
Diaphragm expansion vessel parameters
Nominal volume
Minimum pre-charge pressure
Safety valve response pressure
Table 26 General conditions for diaphragm expansion vessels
1) Install the expansion vessel on site
2) 4-bar safety valve available as accessory
Estimated checking of an integral diaphragm expansion vessel or selection of a separate one
1. MAG pre-charge pressure
p
Form. 1 MAG pre-charge pressure (at least 0.5 bar)
p MAG pre-charge pressure in bar
0
p Static pressure of the heating system in bar
st
(subject to building height)
2. Fill pressure
p
=
a
Form. 2 Fill pressure (at least 1.0 bar)
p Fill pressure in bar
a
p MAG pre-charge pressure in bar
0
3. System volume
Subject to various heating system parameters, the system
volume can be checked in fig. 64.
6 720 645 821 (2010/09) – Logamax plus GB162
1)
p
=
0 st
p 0,5 bar
+
0
expansion vessel for the operation of the Logamax plus
GB162 gas condensing boilers are outlined in table 26.
Unit Logamax plus GB162
l
bar
bar
V (l)
A
2000
1000
500
400
300
175
100
50
40
30
3,5 5 10
7 747 009 801-34.1il
Fig. 64 Standard values for the average water content
of heating systems (acc. to ZVH guideline
12.02 [Germany])
a Underfloor heating system
b Steel radiators to DIN 4703
c Cast radiators to DIN 4703
d Panel radiators
e Convector heaters
Q Rated system output
K
V Average total system water content
A
Example 1
Given
• System output Q = 18 kW
K
• Panel radiators
Checked
• Total system water content = 175 l
( fig. 64, curve d)
System examples
On-site sizing
1
2)
3 (4)
18 30 40 50
Q
(kW)
K
6
a
b
c
d
e
100
65