Worcester 28i Junior Specifications download pdf (Page 18)

5 Combustion Chamber Insulation.

Remove inner casing door and combustion chamber cover.

Slide the damaged insulation panel from the appliance

Rear

Remove heat exchanger. Refer to Fig 61.

Remove the side insulation panels.

Slide the rear insulation forward and up to remove.

Replacement is the reverse of removal. Refer to Fig 50.

6 Pressure Gauge

Remove the clip-on facia cover, cabinet, unscrew the single screw

and lower the facia panel onto the lower support lugs. Refer to

Fig. 39 and 40. Check that the appliance has been fully drained.

Slide the captive clip upwards and remove the pressure-sensing

head. Refer to Fig. 52.

Unclip the gauge head from its mounting bracket and remove.

Refer to Fig. 51.

Check the condition of the O-ring at the pressure capillary head

before fitting the replacement gauge.

7 Relief Valve

Remove the clip-on facia cover, cabinet, unscrew the single screw

and lower the facia onto the lower support lugs.

Check that the appliance has been fully drained.

Disconnect the relief valve discharge pipe .

Pull down the fixing clip and pull out the relief valve. Refer to Fig. 17.

NOTE: The clip does not need to be fully removed.

8 Flow Turbine/ Filter/ Restrictor

Drain the DHW circuit as described at the start of Section 16.

Remove the clip-on facia cover, cabinet, unscrew the single screw

and lower the facia panel onto the lower support lugs.

Separate the turbine in-line electrical connector.

Remove the two fixing clips and withdraw the turbine assembly.



Fig. 51. Pressure Gauge head

Fig. 52. Pressure Gauge connection.

Fig. 50. Combustion Chamber Insulation.

1. Combustion chamber assembly

2. Rear insulation panel

3. Side insulation panel

4. Front insulation panel (fixed to combustion chamber

front cover)

1. Pump

2. Pressure gauge capillary

3. Pressure gauge head

4. Mounting bracket

1. Pump

2. Pressure gauge connection

3. System connection hose

4. Air vent fixing clip

5. Air vent cartridge

6. By-pass pipe

7. 0-Ring

Fig. 54. Water flow turbine.

1. Flow turbine

2. Clips (2)

3. O-ring

4. Filter/Flow restrictor

24i White 8 l/min

28i Blue 10 l/min

If Z is between 425 - 725mm it is not necessary to cut the

terminal assembly or use a second extension duct as the length

can be set telescopically.

If Z is greater than 725mm then two extension duct assemblies will

be required, the first assembly being cut to length as plain tubes.

If more than two extension ducts are needed in any section to

achieve the required length then the final section of the

assembly must not be less than 275mm without cutting the

terminal assembly.

NOTE: The flue duct of the final extension must be 30mm longer

than the air duct.

Each section must be connected to the previous section of the

flue bend by fixing the flue ducts together and then similarly

fixing the air ducts which engage the elbows.

Fit the assembly as described in Section 11.9, 11.10 as

appropriate.

Make good the internal and external brickwork or rendering.

11.13 Vertical Adapter for Horizontal Flues

An adapter is available for an initial short section of vertical flue.

Refer to Fig. 28.

Measure and cut the flue as described in Section 11.12.

The first, vertical, section (equivalent to dimension X) is

measured from the top of the boiler casing. Cut the vertical

section of the extension duct to 167mm less than the measured

distance. Do not remove the socketed ends.

The minimum measured distance is 167mm.

Seal the air duct to the spigot using silicone sealant.

11.14 Completion of the Installation

Check that all the gas and water connections on the manifold

have been tightened.

Undo the two screws and remove the connections cover panel.

Refer to Fig. 29.

Connect the mains supply lead to the appliance and secure the

cable clamp. Refer to Fig. 29.

Check that there is sufficient loose lead to allow the release of the

facia panel assembly.

Connect the earth lead. The earth lead of the mains supply must

be longer than the live and neutral leads.

Fit the facia mounted clock or programmer. Full instructions are

sent with the control. Refer to Fig. 30.

Connect any external controls ensuring that the leads pass through

the appropriate cable clamp. Refer to Section 11 and Fig. 31.

Test for gas soundness as described in BS6891.

If the appliance is not to be commissioned immediately, replace the

connection cover panel and the cabinet.

Check that the gas and electricity services have been turned off.

120mm

100mm

Fig. 27 - Elbow to Flue Turret

Assembly.

Fig. 28 Vertical Adapter.

Flue Duct

Air Duct

Adapter

Flue Spigot

Flue Turret

Bend

*5mm

*When connecting to an elbow the flue duct must be

5mm longer than the air duct.

Fig. 29. Facia connections

ST2

Series

connection

point

1. Controls connector

cover

2. Controls connector

cover fixing screws (2)

3. Facia control panel

4. Earth connection (tags)

5. Earth connection

(screws)

6. Cable clamp

7. Fuse F1 2A (slow)

8. Cable clamps

(pump and fan)

9. ST15 Pump

10. ST1 Fan

11. Fuse F2 1.25A (slow)

12. Commissioning switch

(gas valve mode switch)

13. Internal controls

connectors

14. Mains and external

controls connectors

1 2 ... 13 14 15 16 17 18 19 20 21 22

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Worcester 28i Junior Specifications Page 18

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