Bosch Appliances 12/18, 18/25, 25/32kW instruction manual Water Systems & Pipework

COMMISSIONING INSTALLATION

TYPICAL OPEN VENT SYSTEM
E	S
1000mm min.
F H	R
	T	L
G	R
	L	L
C
	D
A - Appliance expansion vessel	F - Feed & expansion 15mmØ min
B - Extra expansion vessel	G - Appliance
C - Automatic bypass valve	H - Open vent 22mmØ min
D - Drain cock	L - Lockshield valve
E - Feed & expansion cistern	P - Pressure relief discharge

				R
TYPICAL SEALED SYSTEM			T	L
	A
	G			R
		B
			L	L
P	U	C
			D

R

TL

R

TL

D

R - Radiators S - Static head T - TRV

U - To filling system

R

TL

R

TL

D

WATER SYSTEMS & PIPEWORK

IMPORTANT: The boiler should not be allowed t o operat e wit h a ret urn temperature of less than 40°C when the system is up to operating temperature.

PRIMARY SYSTEM PLASTIC PIPEWORK:

•Plastic pipework must not be used for the DHW system.

•Any plastic pipework used for the CH system must have a polymeric barrier, comply with BS 7921 and installed to BS 5955 with 1000mm (minimum) length of copper or steel pipe connected to the boiler.

•Plastic pipework used for underfloor heating must be correctly controlled with a thermostatic blending valve limiting the temperature of the circuits to approx. 50°C with 1000mm (minimum) length of copper or steel pipe connected to the boiler.

PRIMARY SYSTEM/CONNECTIONS/VALVES:

•Do not use galvanised pipes or radiators.

•All system connections, taps and mixing valves must be capable of sustaining a pressure of 3 bar.

•Radiator valves should conform to BS 2767:10.

•All other valves should conform to BS 1010.

•On new installations TRVs must be used on all radiators except the radiator where the room thermostat is sited, this must be fitted with lockshield valves and left open. All installations should have TRVs fitted to radiators within the sleeping accommodation.

•An automatic bypass valve must be connected between the heating flow and return where TRVs are used on all radiators, fitted to give at least a 3m circuit when activated.

•Drain cocks are required at all the lowest points on the system.

•Air vents are required at all high points on the system.

OPEN VENT PRIMARY SYSTEM:

•In order to comply with BS 5449 the feed and expansion pipe and the open vent pipe, (or the combined feed and vent pipe), must be connected to the BSP outlet/s on the right hand side of the primary heat exchanger.

•The feed and expansion cistern (E) must be positioned to provide a static head (S) of at least 1 metre above the highest point in the heating system to the water level in the feed and expansion cistern (E).

•Ensure adequate space is left in the expansion cistern for expansion of the system water.

•No valve shall be fitted in the open vent pipe

(H) or the feed and expansion pipe (F).

•The open vent pipe (H) must be at least 22mmØ.

SEALED PRIMARY SYSTEM:

•Where the system volume is more than 180 litres at 0.5 bar or exceeds 2.65bar at maximum heating temperature an extra expansion vessel (B) must be fitted as close as possible to the appliance in the central heating return.

•Pressurise the extra expansion vessel (B) to the same figure as the expansion vessel built into the appliance.

PRE - INSTALLATION

10

INSTALLATION & SERVICING INSTRUCTIONS FOR WORCESTER GREENSTAR HEATSLAVE EXTERNAL 12/18-18/25-25/32	WATER SYSTEMS & PIPEWORK
8 716 113 389b (09/07)