Preparatory work
7
Greenstar – 6721852556 (2022/11)
4
Preparatory work
4.1
Observe general notices
▶ Remove the packaging, observing all notices in the packaging.
▶ Mount the HIU as close as possible to the most frequently used water
draw-off point.
▶ When assembling the pipework, secure the connections at the HIU to
prevent twisting.
Other components required
NOTICE
Push by due to excessively high differential pressure
The maximum differential pressure in the primary circuit of heat
interface units with integrated differential pressure control valve is
400 kPa (4000 mbar), and 80 kPa (800 mbar) without integrated
differential pressure control valve.
▶ Where necessary, install a suitable control to limit the differential
pressure.
▶ Protect the primary heating circuit with an expansion vessel and
pressure-relief valve in accordance with BS EN 12828.
As the heat interface unit is not always accessible, we recommend using
a central automatic air separator or a deaerator in the primary circuit.
▶ Install drain valves at all the low points in the system.
▶ Install air vents at all the highest points in the system.
▶ Install thermostatic radiator valves in accordance with CIBSE CP1.
DHW - water quality
▶ Comply with limits in the following table.
▶ Comply with UK Water Regulations.
CAUTION
Failure of the station due to calcification of heat exchanger.
▶ If the water hardness is 20°°dH or more, install a water softener unit.
To minimise calcification of the heat exchanger, we recommend you
install a water softener unit if the water hardness is
14°°dH
or more.
Table 4 Suitability of the water supply
Heating water quality
Water treatment and quality for both the primary heat network and
tertiary heating circuit should comply with the water treatment guidance
contained within CIBSE CP1.Additionally, the below additives are
suitable for use with this product.
Table 5 Typical additives for the heating water
Floor heating
To protect the underfloor circuit in the event of faults:
▶ Mount thermal protection valve.
-or-
▶ Temperature switch on the flow pipe to the underfloor circuit
▶ Set the switching point of the temperature switch (minimum
temperature setpoint of underfloor heating c 10 K).
4.2
Pipework installation
Any plastic pipe-work used on the central heating system must have a
polymeric oxygen barrier coating.
▶ Carry out a pipe network calculation to determine the pipework sizes.
Observe specified pressure losses of the HIU.
▶ Fit pipework and connections without stress.
▶ Sufficiently insulate all pipework leading to the HIU (according to
CIBSE CP1 guidance).
Showers/bidets
• Ensure that the shower is suitable for use with mains water pressure.
• If a shower head can be immersed in water or comes closer than
25mm from the top edge of a bath or shower tray spill over level then
an anti-siphon device must be fitted to the shower hose.
• Bidets with direct hot and cold mains water can be used (with the
approval of the local water authority) and must be the over rim
flushing type with shrouded outlets to prevent the fitting of hand held
sprays.
Water pressure
▶ Observe water pressure limits (
specifications).
NOTICE
Risk of damage to household appliances!
Non-return, back flow prevention devices (including those associated
with water meters) fitted to the mains water supply can cause a pressure
build up which could damage the appliance and other household
appliances.
▶ Fit a mini expansion between the non-return valve, back flow
prevention device.
4.3
Installing the discharge pipe
CAUTION
Risk of scalding due to incorrectly installed discharge pipe!
▶ Mount discharge pipe so it cannot pose a danger when discharging
into a drain or tundish.
When the tundish is installed indoors it should have an odour trap. If the
temperatures in the primary circuit are higher than 85°C, we recommend
using a Hotun-Hiflun tundish.
▶ Install discharge pipe from the safety valve [1,3] in a pipe that is
suitable for the maximum operating temperature. Discharge into a
suitable drain or tundish internally. For external discharge, install as
set out in the figure.
▶ Install a partial elbow on the end to prevent freezing.
Unit
Value
Water hardness
°dH
< 20
pH value
6.0 - 9.5
Conductivity
S/cm
10 - 2790
Sulphate
mg/l
< 250
Chloride
mg/l
< 80
BASF Glythermin NF (20-62%)
Sentinel X100 (1-2%)
Fernox F1
Sentinel X200
Fernox F1 express
Sentinel X400
Fernox Alphi-11
Tyfocop Tyfocor L (25-80%)
Hoechst Antifrogen N (25-40%)
MC1+ Protector
Hoechst Antifrogen N+L (40%)
MC3+ Cleaner
Nalco Nalco (1-2%)
MC2 Silencer
Nalco Varidos 1+1 (1-2%)
MC ZERO (25-40%)
Nalco Varidos FSK (22-55%)
