Horne Engineering Ltd
Issue 3 8/05 6
6.4.8 Thoroughly clean all components.
6.4.9 Flush out the valve body by replacing the VALVE COVER (3) and ADJUSTING
SCREW (2) and opening the isolating valves and allowing water at full bore to pass
through the body to the outlet.
6.4.10
If dirt is seen during flushing then carry out the FLUSHING PROCEDURE in
Section 2.
6.4.11 Re-assemble the HORNE 25 TMV (See 6.6).
6.5
MAJOR MAINTENANCE
6.5.1 For this remove the HORNE 25 TMV from the pipework.
6.5.2 Unscrew STRAINER COUPLING NUTS (11) and the OUTLET PIPE
COUPLING.
6.5.3 Lift the valve out of the pipework.
6.5.4 DO NOT grip the valve body in a vice. This could distort the body and jam the
internal parts.
6.5.5 Remove the VALVE COVER (3) and internal parts as referred to in 6.3.1 to 6.3.4.
6.5.6 If the valve body requires de-scaling, remove all "O" ring seals and use a
proprietary fluid for this purpose. Do not put the THERMOSTAT ELEMENT
ASSEMBLY (6) in the descaling fluid.
6.5.7 Inspect the condition of the HOT VALVE FACE and the COLD VALVE FACE. If
the valve faces show signs of deterioration they can be resurfaced as follows :-
6.5.8 Using a mandrel (Tool No. 7342) lap the HOT VALVE FACE using a water
soluble scouring paste. Use 800 grade wet abrasive paper on a flat surface to lap the
COLD VALVE FACE.
6.5.9 Reassemble the HORNE 25 TMV.
6.6 Re-Assembly
6.6.1 When fitting new "O" rings, it is advisable to smear them sparingly with a WFBS
listed silicon grease.
6.6.2 Insert the components into the HORNE 25 TMV in the order shown on Drawing
7311.
