8
GENERAL
Mexico Super CF445 - CF475 -
Installation & Servicing
3
MINIMUM REQUIREMENTS
Fully pumped systems
1.
Separate flow and return connections are used for each
service. All possible configurations are given in Frame
11 and
ONLY those shown should be used.
2.
The schematic pipework graph is based on the
assumption that NO MORE than 8 elbows are used in
the gravity loop, including entry to the boiler.
3.
For each extra elbow in excess of 8, (R) MUST be
reduced by 300 mm (12") or (H) increased by 100 mm
(4")
4.
Whatever value is selected for (R), the value of (H) MUST
be at least that indicated by the graph
4
GRAVITY HOT WATER & PUMPED CENTRAL HEATING
(R)
=
the horizontal distance between the centre
line of the cylinder and the boiler tappings
used - measured along the pipe run
(H)
=
the vertical distance between the top of the
boiler and the base of the cylinder
Notes.
a.
Flow and return pipes should rise vertically
on leaving the boiler.
b.
Horizontal pipes should be ABOVE ceiling
level and as short as possible.
c.
A MINIMUM inclination of 25 mm per 3 m
run (1" per 10') is required to avoid air locks.
If the above conditions cannot be met then
pumped primaries should be used.
1.
Open vent and cold feed connections must be made to the
boiler flow and return tappings according to the options
shown in Frame 11.
2.
The boiler is assumed to be the highest point of the
circulating system.
3.
The circulating pump is positioned on the FLOW - the
vertical distance, between the pump and feed / expansion
tank, must comply with the pump manufacturer's minimum
requirements, to avoid cavitation. Should these conditions
not apply, either lower the pump position or raise the feed/
expansion tank above the minimum requirements of
Caradon Ideal Limited.
4.
The water velocity through the boiler flow / return pipes is
assumed to be below 1 m/s (3 ft./s.) whilst the pump flow
rate is set to provide a temperature difference of 11
o
C (20
o
F)
across the boiler flow / return, at design input.
5.
This information is intended as a GUlDE ONLY and cannot
take into account instantaneous changes in head caused
by the operation of motorised valves, pumps etc.
Due allowance MUST be made if surging is liable to occur.
If in any doubt, contact
Caradon Ideal Limited.
200943-1.p65
3/4/2004, 1:58 PM
8
