Hamworthy Sherborne Series Installation, Commissioning And Servicing Instructions page 48

APPENDIX E - WATER DATA
Model
Water Connections (Flow & Return)
Maximum Water Pressure
Water Content (not including headers)
System Design Flow Rate @ 11°C ΔT Rise
Minimum Flow Rate @ 15°C ΔT Rise
Waterside Pressure Loss @ 11°C ΔT Rise
Waterside Pressure Loss @ 15°C ΔT Rise
E1.1 Water Circulation System
The Sherborne boiler has a low water content & the requirements of minimum water flow are given in the above
table. Recommendations for the water circulation system are given in BS 6644 & CP 342.
The following details are of particular importance for the correct installation of the water circulation system:
•
In a combined central heating & hot water system the hot water storage vessel must be of the indirect
cylinder or calorifier type. The hot water storage vessel should be insulated, preferably with not less
than 75mm (3") thick mineral fibre, or its thermal equivalent.
•
Circulating pipework not forming part of the useful heating surface should be insulated to help prevent
heat loss & possible freezing, particularly where pipes are run through roof spaces & ventilated
cavities. Cisterns situated in areas which may be exposed to freezing conditions should also be
insulated. Furthermore, insulation exposed to the weather should be rendered waterproof.
•
Drain valves must be located in accessible positions which permit the draining of the whole system,
including the boiler & hot water storage vessel.
•
Each boiler module has 1
blue spot) connections. Boilers should be connected by flow & return headers. Headers should be
connected to the system in a 'reverse / return' arrangement (the water flow in each header is in the
same direction) to ensure equal flow in each module, or with a 'single pipe header system'. Figure
E1.1.1 on the following page show typical layouts.
•
Ideally, individual valves should be fitted to each module to enable isolation from the system,
however, the arrangement must comply with the requirements of BS 6644.
•
E1.2 Minimum System Water Pressure
To comply with guidance note PM5 (Health & Safety Executive), the minimum pressure requirements at the boiler are
given below as examples:-
•
Single boiler running at 82°C flow temperature. Minimum head required is not less than 2.0 metres or 0.2 bar.
•
Single boiler running at 90°C flow temperature. Minimum head required = 3.0 metres or 0.30 bar.
•
Modular boiler running at 82°C flow temp & 11°C rise across system. Min head required = 4.4 metres or 0.43 bar.
•
Modular boiler running at 82°C flow temp & 15°C rise across system. Min head required = 6.5 metres or 0.64 bar.
E1.3 Pressure Relief Valve (Safety Valve)
The most important single safety device fitted to a boiler is its safety valve. BS 6644 provides comprehensive
information for the selection & location of safety valves & attention is drawn to the higher capacity requirements of
Boiler Output
60 - 150kW
150 - 300 kW
300 - 600 kW
E1.4 Open Vent & Cold Feed Pipe.
Every boiler or group of boilers should have an open vent pipe & cold feed pipe installed between the boiler & the
first water isolating valve. The minimum bore (mm) of these pipes per installation is shown in the table. The vent
pipe must rise continually, any valve fitted between a boiler & the open vent pipe for maintenance purposes shall
be of the 3 way type such that when closed to the vent pipe the boiler will be open to atmosphere. The vent pipe
shall be protected against freezing where this might occur. See BS 6644 for detailed information on Open Vent &
Cold Feed Pipes.
E1.5 Altitude Gauge (Water Pressure Gauge)
Every boiler or group of boilers should be provided with an altitude gauge complete with isolating valve.
HAMWORTHY HEATING LTD
WATER DATA
BSPT male flow (indicated with a red spot) & return (indicated with a
1/4"
Feed mm Vent mm
25 32
32 38
38 50
- bar g
- litres
- litre/s
- litre/s
- mbar
- mbar
Cold Feed & Vent Pipe Sizes
safety valves for pressurised hot water systems.
46
SHERBORNE
SE65he SE71c
1 BSPT
1/4"
7.0
4.0 5.0
1.39 1.45
1.02 1.05
520
220
280
120
500001167/E