Pipework
Sealed Systems
Maintenance
Controls
Boilers
Radiators
Regulations
Heat Emitters
Pipework
Components
- Expansion vessel
- the capacity depends on:
- initial charge pressure in the system
- volume of water in the system
- Safety valve release pressure
- Filling loop (with check valves)
- Pressure relief valve (usually set to release at 3 bar)
- Pressure gauge
Expansion Vessel
- Use BS 5449 and Domestic Heating Design Guide
| Safety Valve Setting |
3.0 bar |
2.5 bar |
2.0 bar |
| Initial Vessel Charge (bar) |
0.5 |
1.0 |
1.5 |
0.5 |
1.0 |
1.5 |
0.5 |
1.0 |
| Total water content of system (Litres) |
Expansion vessel volume |
| 25 |
2.1 |
2.7 |
3.9 |
2.3 |
3.3 |
5.9 |
2.8 |
5.0 |
| 50 |
4.2 |
5.4 |
7.8 |
4.7 |
6.7 |
11.8 |
5.6 |
10.0 |
| 75 |
6.3 |
8.2 |
11.7 |
7.0 |
10.0 |
17.7 |
8.4 |
15.0 |
| 100 |
8.3 |
10.9 |
15.6 |
9.4 |
13.4 |
23.7 |
11.3 |
20.0 |
| 125 |
10.4 |
13.6 |
19.5 |
11.7 |
16.7 |
29.6 |
14.1 |
25.0 |
| 150 |
12.5 |
16.3 |
23.4 |
14.1 |
20.1 |
35.5 |
16.9 |
30.0 |
| 175 |
14.6 |
19.1 |
27.3 |
16.4 |
23.4 |
41.4 |
19.7 |
35.0 |
| 200 |
16.7 |
21.8 |
31.2 |
18.8 |
26.8 |
47.4 |
22.6 |
40.0 |
| 225 |
18.7 |
24.5 |
35.1 |
21.1 |
30.1 |
53.3 |
25.4 |
45.0 |
| 250 |
20.8 |
27.2 |
39.0 |
23.5 |
33.5 |
59.2 |
28.2 |
50.0 |
