Technical data

13.0 Changing Components

13.16 Gas Valve (Fig. 59)

IMPORTANT: After replacing the valve the CO

must be

checked and adjusted as detailed in Section 14.0

Combustion & Calibration. Only change the valve if a

suitable calibrated combustion analyser is available,

operated by a competent - see section 12.1.

1. Turn the gas cock off and undo the nut under the boiler.

Retain the washer.

2. Remove the electrical plug from the valve.

3. Undo the nut on the gas feed pipe and ease the pipe aside.

It is recommended that the injector washer is changed as well.

4. Remove the screws securing the gas valve to the boiler

bottom panel.

5. Reassemble in reverse order, ensuring the injector washer is

in place, and perform the Calibration Function & Combustion

Check - see Sections 14.1 & 14.2.

NOTE: Check for gas tightness after replacing gas valve.

13.17 Expansion Vessel (Fig. 60)

1. Close the flow and return isolation taps and drain the

primary circuit.

2. Prise off the securing clip and disconnect the braided hose

from the vessel.

3 . Whilst supporting the vessel undo the locknut and

manoeuvre the vessel out of the boiler.

4. Reassemble in reverse order.

Gas Valve

Gas Cock

Fig. 59

Electrical Plug

Expansion

Vessel

Lock Nut

Fig. 60

Washer

Injector

Washer

Gas Feed

Pipe

NOTE: The Injector Washer MUST

be fitted as shown between the

Valve & Pipe. DO NOT fit the

Injector Washer between the Gas

Cock & Valve