15
2000225065A
Table 3. Flow Rate
MODEL
MINIMUM FLOW RATE
24 cxi
774 litres/hr.
30 cxi
1032 litres/hr.
38 cxi
1289 litres/hr.
This is equal to 20
O
C differential at maximum heat input.
4.1 General
The boiler is for use only with sealed central heating systems.
The safety valve is an integral part of the boiler and it cannot be
adjusted.
The digital readout on the controls fascia indicates the system
pressure when there is no central heating demand.
The circulation pump is integral with the boiler.
4.2 Expansion Vessel
The boiler has an integral expansion vessel with a capacity of
8 litres (1.76 gallons), with a charge pressure of 0.5bar.
Note: The expansion vessel volume depends on the total water
system volume and the initial system design pressure. Guidance
on vessel sizing is also given in the current issue of BS5449 and
BS7074 Part 1, for IE refer to the current edition of I.S.813
"Domestic Gas Installations".
4.3 Flow Rate
If it is necessary to alter the flow rate, the system can be fitted
with a lockable balancing valve in the main flow or return pipes
shown as valve “A” in diagram 4.1. The flow rate through the
boiler must not be allowed to fall below that given in table 3.
4.4 Bypass
The boiler is fitted with an adjustable automatic bypass. Ensure
that under no circumstances does the flow rate drop below the
figure specified, refer to table 3 and section 11.6.
4 Heating System