IDEAL icos system HE15 Installation And Servicing page 11

back
4 SYSTEM REQUIREMENTS - continued
General
1. The installation must comply with all relevant national and
local regulations.
2. The installation should be designed to work with flow
temperatures of up to 82
3. All components of the system must be suitable for a
working pressure of 3 bar and temperature of 110
Extra care should be taken in making all connections so
that the risk of leakage is minimised.
The following components are incorporated within the
appliance:
a. Circulating pump.
b. Safety valve, with a non-adjustable preset lift pressure
of 3 bar.
c. Pressure gauge, covering a range of 0 to 6 bar.
d. An 8-litre expansion vessel, with an initial charge
pressure of 0.75 bar.
4. 'Make-up' Water. Provision must be made for replacing
water loss from the system, either :
a. From a manually filled 'make-up' vessel with a readily
visible water level. The vessel should be mounted at
least 150mm above the highest point of the system
and be connected through a non-return valve to the
system, fitted at least 150mm below the 'make-up'
vessel on the return side of the radiators.
or
b. Where access to a 'make-up' vessel would be difficult,
by pre-pressurisation of the system.
5 SYSTEM BALANCING
The boiler does not normally need a bypass but at least
some radiators on the heating circuit, of load at least 10% of
the minimum boiler output, must be provided with twin
lockshield valves so that this minimum heating load is
always available. See note regarding thermostatic radiator
valves on page 10.
Note.
Systems incorporating zone valves which could completely cut
off the flow through the system, must also include a bypass.
BALANCING
1. Set the programmer to ON, for both CH and DHW. Turn
the cylinder thermostat down.
Close the manual or thermostatic valves on all radiators,
leaving the twin lockshield valves (on the radiators
referred to above) in the OPEN position.
icos system -
Installation and Servicing
GENERAL
0 C.
CH Return
Temporary hose
(disconnect after filling)
Ecl 6053
The maximum cold water capacity of the system should
not exceed 143 litres, if not pressurized. However, if the
system is to be pressurized, the efficiency of the
expansion vessel will be reduced and a larger vessel (or
smaller system volume) may be necessary. If the
capacity of the vessel is not considered sufficient for
this, or for any other reason, an additional vessel MUST
C. be installed on the return to the boiler.
0
Guidance on vessel sizing is given in Frame 3.
5. Filling. The system may be filled by the following method:
Through a temporary hose connection from a 'draw-off' tap,
supplied from a service pipe under mains pressure.
Where the mains pressure is excessive, a pressure
reducing valve must be used to facilitate filling.
When installing the filling device, it must be connected as
below to fully comply with the water regulations.
This may involve the fitting of an additional WRAS approved
isolator valve to the mains supply.
i. Thoroughly flush out the whole system with
cold water.
ii. Fill and vent the system until the pressure gauge
registers 1.5 bar, and examine for leaks.
iii. Check the operation of the safety valve by raising the
water pressure until the valve lifts. This should occur
within 0.3 bar of the preset lift pressure.
iv. Release water from the system until the
minimum system design pressure is reached;
1.0 bar if the system is to be pre-pressurised.
water supply
Hose unions
Double check valve
(
note direction of flow
Turn up the room thermostat and adjust these lockshield
valves to give boiler flow and return temperatures not more
o
than 20 C apart.
These valves should now be left as set.
2. Open all manual or thermostatic radiator valves and adjust
the lockshield valves on the remaining radiators, to give
o
around 15 C temperature drop at each radiator.
3. Turn up the cylinder thermostat and adjust the cylinder
balancing valve so that the cylinder achieves a maximum
flow consistent with adequate flow to the radiators. Check
that with only the domestic hot water loop in circuit a
differential temperature of 20
exceeded.
4. Adjust the room and cylinder thermostat and programmer
to NORMAL settings.
Mains
Additional
stop valve
assembly
)
o
C across the boiler is not
11