Table of Contents
Advertisement
5.3
recommendations
26
Average flue pipe resistance coefficients of various flue pipes.
See also manufacturers information.
bend 90E (R/D= 1,0)
bend 90E (right angle)
bend 45E
T-piece
outlet
Table 8 Average flue pipe resistance coefficients
Flue condensation
Flue gases transfer heat when they pass through the chimney.
If the flue gas temperature falls below dew-point, condensation
will occur in the flue. Under normal conditions condensation will
not occur. To prevent condensation the flue should be insu-
lated. More than one atmospheric water heater can be con-
nected to a single flue.
Fan diluted flue system
A fan diluted flue system can be used with this type of water
heater. The principle is to mix the products of combustion with
fresh air drawn from the outside atmosphere to reduce the CO
value below 1 % and so permit the flue discharge to be located
at low level. Duct diameters are selected to give a duct exit
velocity less than 8 m/sec. (See for further instructions Supple-
ment).
The cold water feed pipes should be installed and protected in
General
accordance with local regulations. Generally this means that a
check valve and an expansion valve should be fitted.
Hot water pipes should be thermally insulated.
In order to maintain a constant temperature at all outlets it is
necessary to have a return circuit with a secondary H/W circu-
lator of a correct size.
Only the water heater pump is supplied with the R18.
The heat exchanger is made of copper, galvanised pipes
must not be used.
With the R18 water heater an expansion vessel should be
included to avoid water being expelled via the safety valve
when the temperature rises.
The primary pump must run continuously when the water heat
er is in operation.
To avoid the formation of steam, the minimum water pressure
must be 1,5 bar at a maximum temperature of 90 °C.
Some variation in water temperature can be due to an
increased demand coincident with a variation in water pressure.
To avoid this a water governor should be used.
When using a water softener it is necessary to include a non
return valve.
18IP22B
ζ = 0,5
ζ = 1,3
ζ = 0,5
ζ = 2,0
ζ = 1,5
2
Advertisement
Table of Contents
