4
1. GENERAL
1.1
Description of the
appliance
Construction of the water heater is in
accordance with the European
standard for gas heated water storage
heaters for sanitary application (EN89).
The appliance thus meets the European
Directory for Gas Appliances and is
therefore entitled to carry the CE-
marking. It is an open flued appliance
without a fan and with a combustion
products discharge safety device
(category B
11BS
). The water heater is
suitable for a maximum working
pressure of 8 bar. The water heater
tank is manufactured from low carbon
sheet steel and is glasslined on the
inside. In addition the tank is fitted with a
sacrificial anode as extra protection
against corrosion. A thick, CFC-free, PU
insulation layer covered in a steel jacket
reduces unnecessary heat loss. When
the appliance is filled with water it
continuously is under water pressure.
As hot water is drained from the tank,
cold water is added immediately. Four
flue baffles have been placed in the flue
tube to improve heat tranfer. The flue
gasses pass their heat on to the water
by means of radiation and convection.
The exhaust of the flue gasses is
realized by natural thermal draught (see
figure 1).
Dead legs on a hot water installation are
undesireable. Where possible they
should be avoided. When the inclusion
on the system of a dead leg is
unavoidable the following restrictions
should be applied:
- for pipes not eceeding 19 mm. inside
diameter; maximum length of dead leg
permitted 12 metres;
- for pipes exceeding19 mm. but not
exceeding 25 mm. inside diameter;
maximum lenght of dead leg 7,5
metres;
- for pipes with an inside diameter
exceeding 25 mm. maximum length of
dead leg 3 metres.