2. GENERAL INSTRUCTION
2.1
DESCRIPTION
The KESTON C36 Combi and C36P Combi combination boilers utilise the latest in
condensing technology to produce a high efficiency boilers that deliver an exceptional hot
water flow rate with SEDBUK A rated efficiency.
The C36 Combi and C36P Combi are unique in concept and design. They comprise a
high efficiency stainless steel heat exchanger coupled with a low emissions burner to
deliver ultra high efficiency condensing mode operation and a plate-to-plate heat
exchanger for domestic hot water production all within a compact wall hung cabinet. The
unit automatically adjusts gas and air rate according to demand to give a heating output in
the range of 7.4kW to 28.0kW [condensing]. The integral pump assembly is automatically
speed controlled to best match water flow rate to heat output & further increase appliance
efficiency. The efficient plate-to-plate heat exchanger provides superior levels of
performance: its has an outstanding hot water performance of 14.5 L/min (at 35C
temperature rise) and 17.0 L/min (at 30C temperature rise - EN625)
In addition, the boilers feature a connection for an optional outside sensor to enable the
boilers inbuilt weather compensation option which delivers enhanced user comfort levels
with peak operating efficiency due to the lower flow temperatures involved. The boiler also
features an “Opentherm” connection point for the Keston Room Control module which
provides further advanced user control for room temperature compensation and optimum
start. The boiler fascia provides separate user controls for central heating and domestic
hot water temperatures. The advanced hot water flow monitoring ensures exceptionally
stable hot water temperatures are provided. The boilers have the added advantage of very
high efficiency, and small diameter muPVC plastic flue which can be extended up to 20
metres horizontally or vertically.
The Keston C36 Combi uses a variable speed combustion blower to deliver a premix of
gas and air to a downward firing burner in a high efficiency, single pass heat exchanger.
The flue system is room sealed and fan powered. The ignition is direct spark and fully
automatic. The boiler housing is
not
waterproof and should be installed in a position
where it will always be dry. Combustion air is drawn from the cabinet which is connected
to outside atmosphere via a small diameter plastic intake pipe. The cabinet therefore
remains under negative pressure at all times the boiler is operating.
These boilers are designed for use as part of a sealed water central heating system with
fully pumped circulation. The pump, an 8l expansion vessel and associated safety devices
are all fitted within the boiler.
The boiler heat exchanger is made from highly corrosion resistant stainless steel in
corrugated pipe form which provides massive surface area within a compact dimension.
The hot combustion gases from the down firing burner pass around the stainless steel
pipes imparting heat into the system water. The integral variable speed pump within the
appliance cabinet ensures the heat exchanger receives correct water flow when firing.
The C36 Combi is not a high water content boiler and does not contain the metal mass, or
water volume, of a cast iron or steel boiler. This boiler is of low mass and low water
content and therefore responds faster when there is a call for heat. The C36 Combi
features full user diagnostics, integral frost protection function, automatic pump and fan
exercise in periods of inactivity, anti cycle control and dry fire protection.
2.2
BOILER SCHEMATIC
Air is drawn into the boiler through a 50 mm muPVC (BS5255 and/or BSEN1566-1 and
BSEN1329) plastic pipe or, alternatively, via a 75mm Keston composite plastic pipe. Gas
is mixed with combustion air at the inlet to the fan. The gas flow is automatically regulated
by the gas valve according to the air flow generated by the fan. The gas and air are
thoroughly mixed in the blower and fed into the burner located at the top end of the heat
exchanger module. The gas and air mixture is ignited by a direct spark ignition control
WD388/0/2004 Chapter 2 : General Instruction The Keston C36 Combi & C36P Combi Boilers
Installation & Servicing Instructions
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