Hydraulic valve kit instructions

Figure 1

Contents list

Drawing pos	Quantity	Size(Diameter)	Description	Position	Causes of damage notes
105	2	19mm	3-way valve mechanism O-rings	Left & right porting cone large	Insufficient inhibitor
106	1	22mm	Hydraulic valve-pump body union O-ring	Pump body / hydraulic connection	Frost and insufficient inhibitor
107	1	20mm	By-pass-3-way valve union O-ring	Bypass/porting block	Change if required
108	2	25.3mm	CH flow and return O-ring ¾”	Brass flow and return connection	Change if required
109	2	27mm	3-way valve external O-ring (1 already fitted to valve)	Left & right-side porting block	Insufficient inhibitor
110	1	17.3mm	By-pass O-ring	Bypass/diaphragm housing	Insufficient inhibitor
112	2	17.8mm	DHW in/out O-ring ½”	Brass hot & cold connection	Frost
117	2	6mm	3-way valve axis O-ring	Left & right porting cone small	Insufficient inhibitor
119	1	n/a	Hydraulic valve-pump body union clip	Clip pump body / hydraulic assembly	Change if required
115	2	17mm	Plate exchanger special joint ½”	Hot and cold plate heat exchanger	Frost and insufficient inhibitor
116	2	20mm	Plate exchanger special joint ¾”	Flow & return plate heat exchanger	Frost and insufficient inhibitor
118	1	n/a	3-way valve spindle	Spindle between left and right porting block	Insufficient inhibitor
151	1	M5X75	Hydraulic valve screw	Diaphragm housing	Change if required
120	1	n/a	Complete hydraulic valve	n/a	n/a

Advisory guidance for reassembly

WRAS approved silicone grease will be required
Ensure primary circuit is flushed and cleaned before replacing any parts
The primary circuit water needs to be 25% filled with Fernox Alphi 11 (combined antifreeze inhibitor mix) for minimum protection for central heating system components with a frost protection of -11 degrees centigrade
If the flat plates on the DHW heat exchanger have popped out the DHW heat exchanger will need to be replaced

O-ring/seal replacement instructions

Remove hydraulic assembly
Remove the 3 long screws securing the plate heat exchanger (MCB2160) to the black plastic components of the hydraulic assembly
Remove the clip joining the brass housing part of the complete hydraulic valve to the right of the porting block
Now separate the complete hydraulic valve from the porting block – Figure 2
Remove the clip between the flow block and the porting block – Figure 2

Replace the 3-way valve spindle (No.118) ensuring the brass spacer is cleaned and slid onto the 3-way valve spindle from the longest end up against the cirr clip on the 3-way valve spindle – Figure 4

Replace O-rings on porting cones, drawing numbers (105 x 2 and 117 x 2) – Figure 3

Fit the 3-way valve spindle with the right-hand porting slid on to the 3-way valve spindle into the right-hand side of the porting block
Fit the left porting onto the spindle through the left side porting block
Reassemble the right-hand side of the porting block to the complete hydraulic valve sliding the clip back in and ensuring the O-rings (No.109 & 110) are securely fitted
Fit spring and brass steering wheel shaped spring guide onto flow side of hydraulic assembly
Clamp together ensuring O-ring (No.109) is securely fitted. Then slide the clip home. Replace seals (Nos. 115 x 2 & 116 x 2) onto the plate heat exchanger. Now mount the hydraulic assembly onto the plate heat exchanger ensuring the seals are seated inside the main body – Figure 1 using the screws, (the right-hand screw No. 151) may need replacing if you had a very early complete hydraulic valve with a short screw
Now add a small amount of silicone grease to the flow restrictor and refit into the cold inlet on
Replace O-rings (Nos 112 x 2 & 108 x 2) onto the hydraulic inlet unions (MCB2345) attached to the base plate (MCB2420) of the boiler – Figure 1
Refit complete hydraulic assembly back into boiler. Please use O-ring (No. 106) & clip (No.119) for connection to the pump body – Figure 1

Download a copy of this help article