2. GENERAL INSTRUCTION
2.1
DESCRIPTION
The KESTON Q37 and Q37P boilers utilize the latest in condensing technology to
produce a high efficiency boiler with SEDBUK A rated efficiency plus advanced controls to
maximize operational efficiency.
The Q37 is unique in concept and design. It comprises a high efficiency stainless steel
heat exchanger coupled with a low emissions burner to deliver ultra high efficiency
condensing mode operation within a compact wall hung cabinet. The unit automatically
adjusts gas and air rate according to demand to give a heating input in the range of 9.2kW
to 38.0kW (GCV). The integral pump assembly, in the Q37, is automatically speed
controlled to best match water flow rate to heat output & further increase appliance
efficiency.
In addition, the boiler 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 2 stats (e.g. central heating and
domestic hot water temperatures). 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 Q37 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.
The boiler is suitable for connection to open vented or, preferably, sealed systems. The
pump is 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 Q37 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 Q37 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
system and burns with a blue flame just off the surface of the burner. As the hot products
of combustion pass downwards, they are cooled by exchanging heat with the circulating
water which enters the heat exchanger at the bottom of the heat exchanger. The optimum
heat input is detected by monitoring flow and return temperatures and is adjusted by
WD500 Chapter 2 : General Instruction
The Keston Q37 & Q37P Boilers
Installation & Servicing Instructions
Page : 4
