© MHG Heating Ltd
7
MHG Heating Ltd, Unit 4 Epsom Downs Metro Centre, Waterfield, Tadworth, Surrey, KT20 5LR
Phone 0845 6448802 Telephone. 0845 6448803 Fax. Email
Website www.mhgheating.co.uk
010313
Draft
Installation Procedure
Read this instruction book carefully before proceeding.
The cylinders are mains pressure products and are unvented. Unvented hot water systems should only be fitted and serviced by competent
persons, as defined by the current edition of the Building Regulations (England and Wales) Approved Document G or equivalent regulations.
The expansion vessel is fitted outside the case.
Please verify which model you have before proceeding with the installation.
The unit must be stored in an upright and dry place before installation.
Only use the components supplied with the cylinder. Failure to do so is potentially dangerous and will invalidate the product guarantee.
The cylinder should be connected to a public mains water supply through the Inlet Control Group supplied.
Indirect models must only be used with pumped primary system.
The standard cylinders cannot be used with solid fuel boilers.
The cylinder and mains pressure systems require an annual safety check by a competent person.
Failure to carry out this safety check will invalidate the warranty.
Measure the area in which you plan to install the cylinder and ensure that the floor can support the weight of the cylinder when full.
Unit
Full Weight
kg
Height
mm
Diameter
mm
Standard Heat Up
Time to 55C (mins)
Standard Reheat
time to 60C after
70% draw-off
(mins)
High Recovery
Heat Up Time to
55C
(mins)
High Recovery
Reheat time to 60C
after 70% draw-off
(mins)
90
125
750
510
26
18
13
9
125
165
935
510
36
25
19
13
150
195
1060
510
37
26
19
13
170
220
1200
510
36
25
19
13
200
250
1120
554
33
24
17
12
250
310
1330
554
35
25
18
13
300
360
1650
554
40
29
20
15
400
480
1590
660
46
34
23
18
500
580
1835
660
52
39
25
20
600
715
1435
822
69
34
51
29
700
825
1664
822
72
36
51
28
800
946
1864
822
74
38
54
30
900
1075
2064
822
78
35
53
29
1000
1185
2314
822
86
37
50
28
Please note the above figures are for guideline purpose only.
Heat-up and re-heat times are for indirect models.
All dimensions and weights are nominal.
The Cylinders are designed to work efficiently under most water flow and pressure conditions. However, the full potential of a mains pressure system is
unlikely to be achieved if the flow falls below 20 L/Min and the dynamic pressure is less than 1.5 bar.
To prevent damage to the coil and cylinder connections, make any soldered joints before connecting pipework to the cylinder.
Position the unit vertically and make the incoming cold water connection to the fitting labelled “mains water inlet”.
For commissioning and later maintenance purposes it is essential to fit a service valve immediately before the connection to the Inlet Control
Group.
Installing the Inlet Control Group
The mains cold water supply should first pass through the pressure reducing valve, which reduces the pressure to 3.0 bar - this is factory set
and cannot be adjusted - and then through the 6.0 bar expansion valve .
The Inlet Control Group includes a single check valve and filter.
*NB
Upon commissioning. The expansion vessel pressure should be adjusted to 0.2 bar less than the incoming water pressure.
