Thermona Therm 28 KD, Руководство по установке

Страница: 3 / 26

3
1. USAGE
Hanging condensing boilers THERM 28 KD are modern gas appliances with a forced flue exhaust (they need no
chimney) suitable for heating in such houses whose heat losses do not exceed 28 kW. The combustion process
taking place in these appliances is based on the principles of steam condensation. The THERM 28 KDs are boilers
with maximum efficiency and minimal emissions to the air, which means that their operation is very economical
and environment friendly. Their output is adjustable ranging from 18 to 100 % and it adapts itself automatically to
the heating needs of the premises.
The high technical standard is guaranteed by the use of top components from the world’s best producers.
The engineering solutions of the THERM 28 KD boilers are the following:
THERM 28 KD
– modification of the boiler used only for warming of the heating appliance (the actuating
circuits enabling external connection of a three-way valve necessary for the warming of the DHW supply tank have
been maintained)
THERM 28 KDZ
– used for warming of the heating appliance and for warming of the external DHW supply
tank with a continuous output modulation in both regimes
THERM 28 KDC
– for warming of the heating appliance and DHW through-flow heating with continuous
output modulation in both regimes
All boilers are provided with an expansion vessel with a capacity of 7 litres.
Warning: For the proper boiler functioning, it is necessary to keep the minimum water pressure in the heating
system at 0.8 bars (measured when the water is cold). If the boiler is connected to a system with an open expansion
vessel, the expansion vessel must be placed at least 8 m above the boiler.
2 . GENERAL DESCRIPTION OF THERM 28 KD BOILERS
The THERM 28 KD gas boiler is made up of a supporting frame to which all operative elements are attached.
In the upper part of the frame there is a stainless compact condensation device Giannoni that connects the
combustion chamber with the burner and the two-chamber exchanger. The heat-mediating surface of the
exchangers is made of circular tube plates. These must be protected against the dirt coming from the heating system
which might clog them up. Therefore, it is necessary to install a filter at the return water inlet into the boiler. The
collector at the outlet of the heating water is equipped with an automatic deaerating valve and a temperature
indicator. The removable front wall of the device is fitted with two electrodes (ignition electrode and ionizing
electrode), with a tubular burner and a modified pipiline conducting the air-gas mixture.
The approriate rationing of the air-gas mixture and its mixing is ensured by a mixer and a special gas fitting. The
latter contains a gas pressure regulator, two solenoid blocking valves and a ratio control of the outlet gas volume
with the elements for mechaical setting. The setting of synchronous ratio control is possible only if a special
instrumentation device is used. The whole system is based on the principle that the volume of the added gas is
directly proportional to the volume of air supplied by the ventilator and passing through the mixer. The boiler
output is consequently dependent on the volume of the air that is circulating in the system for the purposes of
combustion.
The running speed of the ventilator is fully controlled by means of electronic devices, which ensures a wide
output range of the boiler. The air supply for the ventilator is ensured by a modified pipeline from the connecting
set.
The exhaust of the condensed fluid from the condensation device, as well as from the pipelines of the flue exhaust
and air supply is realized through hoses conducting the condensate to a siphon trap, from where it is conducted
away, outside the boiler.
The adequate supply of combustion air as well as the forced flue exhaust outside the boiler is usually ensured by
coaxial tubes that lead either horizontally through the perimeter wall or vertically over the roof structure out into
the open space. The tubes must be installed in such a way that prevents the potential freezing of the exhaust ending
(this might happen due to the low temperature of the streaming flue). For this reason it is crucial that the vertical
tube be topped by a roof chimney while the horizontal tube must be installed with a moderate fall in the direction
from the exhaust to the boiler.
At the return water inlet there is a service pump Grundfos / Wilo that drives the water through the boiler. The
sufficient flow of the heating water is ensured by a flow-switch that is a part of the multifunctional flue collector
GRF 3. It is installed there together with a by-pass and a valve used for the refilling of the heating system from the
DHW circuit (or, where applicable, from the external connection), and the bleed valve. The flue collector is further
connected to a safety valve controlling the potential excess pressure in the boiler.
The heating water outlet of the THERM 28 KDC and KDZ boilers is fitted with a motor-driven three-way valve
by means of which the functions of DHW warming and warming of the heating appliance are kept apart.
The process of DHW warming in the THERM 28 KDC boilers takes place within the desk exchanger.