MHS Boilers Ultramax WM 100, Руководство по эксплуатации и техническому обслуживанию, Страница: 10 / 50

MHS Boilers Ltd ©
191007
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2.2.2 Description of principal components
Fan [9]
The fan pulls in and compresses the combustion air, drawn from inside the casing of the boiler.
The fan is a DC current fan equipped with a speed feed-back signal. This speed feed-back signal
is transmitted back to the controller, which makes the necessary corrections.
Gas train
The main component of the gas train is the gas valve [17]. The gas quantity is controlled according
to the quantity of air. The air quantity varies with the speed of the fan. The gas train is equipped
with a test point through which the gas pipe can be vented or the gas inlet pressure can be measured.
Burner/heat exchanger package [15]
After the gas/air mixture has been correctly mixed, it flows into the burner via the inlet channel.
Due to the overpressure, the gas/air mixture is forced through the burner to the external surface
of the burner for combustion.
The heat exchanger is made of smooth stainless steel tubes in the form of coils. It essentially
consists of two parts; one part is located immediately next to the flame, where the major portion
of the heat transfer between the combustion gases and the water takes place. The other part
functions as a condenser for the flue gases, where the transfer of latent heat takes place.
Stainless steel water distribution manifolds ensure optimum water flow through the heat exchanger.
Water connections
These consist of a flow connection [4] and a return connection [7]. There is a water temperature
sensor [16] on the flow connection which, apart from controlling the burner load, also monitors
the water flow in the boiler. The latter is done in combination with the flue gas temperature sensor
[8].
Boiler pump [20]
The boiler pump of the types 45, 65 and 85 is located in the return connection of the boiler and
is electrically connected directly to the corresponding terminals in the control panel. The boiler
pump of the types 100 and 120 will be supplied by the installer and can be directly connected to the
return connection of the boiler. (Max 1 Amp) The capacity and the head of the pump is adequate to
overcome not only the boiler resistance but also some system resistance (see table 1). In the types 45
- 85, the pumps have three-stage modulation, depending on the load.
Condensate drain [13]
The boiler is equipped with a bottle trap. This bottle trap is located on the bottom side of the appliance
and should be easily filled with water prior to operation of the unit.
Frame [14]
The frame is the load bearing part of the boiler. All the components are installed on it.