Concord CX -
Installation
5
GENERAL
Boiler Size
Cold Feed
Open Vent
CX 40 - 50
3/4
"
1"
CX 60 -100
1"
1
1/4
"
Sealed system filling point - refer to Frame 8
Flow and return connections are 2" BSP.
A 1" BSP tapping is provided in the redundant return flange for
the cold feed or expansion vessel connection.
Safety Valve
A safety valve must be sized and fitted in accordance with BS.
6644 for every type of system. The valve should be set at 0.7
bar (10 lb/in.
2
) above the operating pressure in the boiler. The
maximum safety valve setting is 0.7 bar (10 lb/in.
2
) above the
maximum design operating pressure of 4.5 bar (65 lb/in.
2
).
Cold Feed/Open Vent
The independent cold feed and the open vent must comply
with BS. 6644 and be of the following minimum size.
1
WATER CONNECTIONS
Control is by a slow opening combination gas control incorporating
a thermocouple flame failure device and mains voltage gas valve.
The control box has a terminal plug connection for mains input.
ELECTRICAL CONTROLS
The basic boiler is supplied with 2 printed circuit boards; designated
board No. 1C and board No. 6A.
Board No. 1C contains an adjustable electronic boiler thermostat
and board No. 6A contains a fixed setting pump overrun timer. A
preset overheat thermostat is also provided.
OPTION KITS
Controls option
Three L.E.D.s are fitted to the boiler upper front panel fixing
indicating:
z
Boiler on
z
Overheat thermostat operation
z
Pilot failure (Lockout)
The facility for wiring remote indication of the above 3 conditions
is also provided.
An L.C.D. screen gives digital information of water flow and of
water flow temperature.
Four additional ‘plug-in’ printed circuit boards; ‘No. 2, ‘No. 3', ‘No.
5’, and ‘No. 21’ are contained in this kit for fitting in the upper
control panel.
Pressure gauge kit
In addition to the above control kit, an optional pressure gauge
is also available for the range of boilers. Details for fitting are
included with the pressure gauge.
Downdraught thermostat kit
This kit is optional when used on a single CX installation, but
mandatory when used on a multiple boiler installation.
DUTY
The range of boilers is suitable for: Combined indirect pumped
domestic hot water
and
central heating systems; Independent
indirect pumped domestic hot water
or
central heating systems.
Fully pumped systems may be open vented or sealed.
The range of boilers is NOT suitable for:
1.
Gravity DHW systems.
2.
Gravity heating systems.
3.
Direct domestic hot water supply.
WATER CIRCULATION SYSTEM
Due to the compact nature of the boiler the heat stored within the
castings at the point of shutdown of the burner must be dissipated
into the water circuit in order to avoid the overheat thermostat
tripping. In order to allow pump operation after burner shutdown
the boiler control box incorporates a pump overrun facility which
operates for approximately 6 minutes after burner shutdown and,
in order to make use of this, the pump must be wired to the
appropriate terminal L
2
(pump) in the boiler control box.
1.
The minimum flow rate as given in Table 4 must be
maintained whenever the boiler is firing and during the pump
overrun period.
2.
During the period of pump overrun there must be an open
circuit of adequate water volume and/or load. The minimum
size of this circuit is given by the use of Graph 1.
Examples shown on Graph 1
a.
For the
CX100 and CX 90
the minimum circuit during pump
overrun could be a load of 6 kW with a volume of 31 litres or
any other combination given by the relevant line.
b.
For the
CX 80 and CX 70
the minimum circuit during pump
overrun could be a load of 2 kW with a volume of 45 litres or
any other combination given by the relevant line.
The above circuit capacity during pump overrun may be
Summary of Contents for Concord CX40
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