Worcester Highflow 400 RSF Installation And Servicing Instructions page 38

Remove the facia as described in Section 15.1.
Remove the spring clip from the thermostat pocket located on
the front left hand side of the heatbank.
NB. There are two thermostat phials fitted in the pocket. The Hot
Water thermostat phial is at the front of the pocket. To identify
the phial follow the capillary tube from the thermostat body
located inside the control box (marked on the facia "Hot Water"
thermostat) to the thermostat pocket.
Ease the phial out of the pocket and unclip the capillary from the
left hand side of the cabinet panel.
Unscrew the two screws on the underside of the control box
securing the mounting bracket to the control box. Ease the
bracket out of the control box allowing the capillary tubes to
feed through the slot in the rear of the control box.
Unscrew the left hand central clamping nut. Pull off the two
electrical connections from the rear of the thermostat. Push the
thermostat body back to disengage the spindle from the
mounting bracket. Withdraw the thermostat threading the
capillary through the slot in the rear of the control box and
discard.
Fit a new thermostat and re-assemble in the reverse order. The
capillary of the replacement thermostat must be uncoiled to
assist its passage through the control box opening. Ensure the
capillary is re-clipped to the left hand side panel, clear of any hot
surfaces and without tight bends. Apply a smear of heat sink
compound to the thermostat phial and replace the spring clip
into the thermostat pocket.
Reassemble the appliance in the reverse order.
13. Heating Thermostat. See Figs. 9, 16, 41, 53 and 54.
Check that the electricity supply to the appliance is turned off.
Remove the cabinet front panel, place the facia and control box
in the Service Position, as described in Section 14.2 a and b.
Remove the facia as described in Section 15.1.
Ease the spring wire retaining clip off the top location on the
front of the top manifold assembly. Pull the retaining clip and
capillary gently downwards out of the thermostat pocket located
in the top manifold. Continue pulling gently downwards until the
phial is clear of the thermostat pocket. Remove the spring wire
retaining clip and retain. Unclip the capillary from the left hand
side of the cabinet panel.
Unscrew the two screws on the underside of the control box
securing the mounting bracket to the control box. Ease the
bracket out of the control box allowing the capillary tubes to
feed through the slot in the rear of the control box.
Unscrew the right hand central clamping nut. Pull off the two
electrical connections from the rear of the thermostat. Push the
thermostat body back to disengage the spindle from the
Fig. 40. Hot water thermostat and
heatbank overheat thermostat.
Heat bank
Spring clip
Thermostat
pocket
Hot water thermostat
phial
Capillary
Heat bank overheat
thermostat
Capillary
mounting bracket. Withdraw the thermostat threading the
capillary through the slot in the rear of the control box and
discard.
Fit a new thermostat and re-assemble in the reverse order. Apply
a smear of heat sink compound to the thermostat phial. The
capillary of the replacement thermostat must be uncoiled to
assist its passage through the control box opening. Ensure the
capillary is re-clipped to the left hand side panel, clear of any hot
surfaces and without tight bends. The spring wire retaining clip
must be re-located on the capillary and in the thermostat pocket.
Clip back into position on the top of the manifold assembly.
Reassemble the appliance in the reverse order.
14. Water Filter Primary System. See Figs. 9, 16, 41 and 47.
Fig. 41. Heating thermostat & water filter
Ease spring wire retaining
clip off the top location on
the front of the manifold
Heating thermostat
pocket in underside
of top manifold
Spring wire retaining clip
Check that the electricity supply to the appliance is turned off.
Remove the cabinet front panel, place the facia and control box in
the Service Position, as described in Section 15.2.a.
NOTE: It is not necessary to drain the complete appliance. Fit a 5mm
dia. plastic pipe to the manual air vent and drain the top manifold.
See Fig. 51.
Remove the heating thermostat phial as described in Section 15.13.
Using a pozi drive 'chubby' type screwdriver remove the screw and
clip securing the heating thermostat pocket into the top manifold.
Retain the screw and clip. See Fig. 41.
Ease the heating thermostat pocket out of the top manifold and
clear of the appliance.
The water filter is located inside the top manifold. Remove the filter
and clean or replace.
Reassemble the appliance in the reverse order using a new 'O' ring
seal. Ensure the securing clip and screw are correctly located and
the heating thermostat phial and retaining clip are correctly
assembled.
15. Hot Water High Limit Thermostat. See Figs. 9, 16, 42 and 53.
Check that the electricity supply to the appliance is turned off.
Remove the cabinet front panel, place the facia and control box
in the Service Position, as described in Section 14.2 a and b.
Remove the facia as described in Section 15.1.
Remove the flow switch and lay to one side. Refer to Section
15.3-30.
Slacken the two M3 taptite screws holding the high limit
thermostat to the hot water flow pipe. Ease the thermostat body
anti-clockwise to release.
Unplug the thermostat leads marked, X16 (DHW Overhea),
from the control board and the earth lead from the earthing
38
Top manifold
assembly
Heating
thermostat
pocket
Water filter
'O'ring seal
Heating thermostat phial
Capillary