Fitting
25
Worcester Commercial Boiler Series – 6720814332 (2019/04)
To make maintenance easier:
▶ Mount a hydraulic isolation valve in the supply and return line.
▶ Connect the flow and return pipes to the boiler, making sure they are
free of stress. The minimum diameter of the flow and return pipes
must be 1½" (Ø 35 mm).
5.7.1
Gas connection
▶ Seal the gas connection on the boiler using an approved sealant [1].
▶ Use a gas isolation valve [2] with a diameter of at least 1".
▶ Connect the gas pipe without stress to the gas isolation valve.
Fig. 39 Installing the gas isolation valve
[1]
Sealing agents
[2]
Gas isolation valve
5.7.2
Mounting the pump
▶ Select a pump based on the technical data (
▶ Take the required flow rate into account (
If a low loss header is not used:
▶ Select a pump that has a residual head of at least 200 mbar at the
required flow rate.
▶ Install the pump [6] in the return pipe [5].
Fig. 40 Connection of the heating water pipework
[1]
Flow pipe
[2]
Pressure Relief Valve
[3]
Hydraulic isolation valve
[4]
Pressure gauge
[5]
Gas isolation valve
[6]
Return pipe
[7]
Pump
[8]
Non-return valve (only mandatory in cascades)
[9]
Drain & fill valve (DFV)
[10] Expansion vessel
[11] Dirt trap
5.8
Install the low loss header
If the residual head is insufficient with the required flow rate (
page 12), a low loss header [1] must be installed to hydraulically
separate the boiler and secondary circuit pumps.
Fig. 41 Installation of the low loss header
[1]
Low loss header
[2]
Expansion vessel
[3]
Pump
[4]
Hydraulic isolation valve
[5]
Pressure differential controller (bypass)
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