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3.0 INSTALLATION
3.1 IMPORTANT INSTALLATION POINTS
3.1.1
The Hotflo unvented water heater MUST be fitted with a Pressure
(expansion) Relief Valve. This MUST be fitted to the cold water supply
near the heater.
FAILURE TO PROVIDE ADEQUATE PRESSURE RELIEF WILL
INVALIDATE ANY GUARANTEE AND LEAD TO A DANGEROUS
INSTALLATION.
3.1.2 Expansion can take place within the cold water supply
PROVIDED THAT BOTH :
(a) Backflow in the main is not prevented by any stopvalve with loose
jumper, check valve, pressure reducing valve or similar
AND
(b) Hot water expansion does not enter a branch to a cold water outlet
(see Figure 01, page 3 for expansion pipe lengths).
Note: Both the above conditions must be met. Additionally expansion
within the cold water supply will not be possible if the static supply
pressure exceeds 0.41 Mpa (4.1 bar).
3.1.3 If any of the conditions in 3.1.2 above cannot be met, expansion must
be accommodated using an Expansion Vessel. To ensure all expansion
takes place in the vessel, a
Check V
alve must also be fitted (see Fig.
03, page 5). Use Accessory Pack U5 code no. 95 970 356.
3.1.4 If the static supply pressure exceeds 0.41 MPa (4.1 bar), a Pressure
Reducing Valve must be fitted to the cold main supply. If a Pressure
Reducing Valve is used, an Expansion Vessel must also be used
(see Fig. 04, page 5). Use Accessory Packs U1 and U5 code no.’s
95 970 352 and 95 970 356.
3.1.5 Where specifications demand the fitting of a Temperature/Pressure
Relief Valve, one can be fitted on site (see Fig. 04, page 5). Use
Accessory Pack U6 code no. 95 970 359. NOTE the fitting of Pack
U6 does not alter the requirements detailed in points 3.1.2 to 3.1.4
above.
3.1.6 National Wiring rules may contain restrictions concerning the installation
of these units in bathrooms.
3.1.7 The installation must be carried out in accordance with the relevant
requirements of:
• The appropriate Building Regulations either The Building
Regulations, The Building Regulations (Scotland) or Building
Regulations (Northern Ireland).
