All heating coils can be manufactured to suit either vertical or
horizontal air flow, but the application must be specified when
Coils are designed for ‘Contra-Flow’ i.e. with the water flow connection

on the air leaving face of the battery such that the heating medium is
flowing in the opposite direction to that of the air. This gives the
maximum logarithmic mean temperature difference and therefore the
maximum performance. Coils can be designed for ‘Parallel Flow’ but this
must be specified at the enquiry stage. One row and two row coils with
opposite side connections can be installed with the primary tubes either
vertical or horizontal. Coils with more than two rows and one row or two
row coils with connections on the same side must be installed with the
primary tubes horizontal as shown in the illustration.Hot water coils are available in depths from one to sixteen rows with
alternate rows equally staggered, to obtain maximum heat transfer.Heat Transfer Surface
The primary
tubes are manufactured from solid drawn seamless copper tube.
Fins are of the smooth plate type produced from aluminium, vinyl coated
aluminium or copper and are punched with self spacing collars. Plain
tube coils are available for anti-frost applications or where the
pre-heating of unfiltered air is required.
The primary tubes are mechanically expanded into the pre-formed collars
thus assuring a good metallic bond between the fins and tubes. This
results in uniform heat transfer with guaranteed performance throughout
the life of the coil. The tubes are brazed or silver soldered into
copper return bends ( where applicable ) terminating in tubular copper
flow and return headers each provided with a B.S.P. screwed male
connection. Flanged connections are available on request.
The heating surface is housed in a casing produced from galvanised sheet
steel. Where the primary tubes pass through the casing, smooth belled
holes are provided to permit freedom of movement for expansion and
contraction. The casing is produced in channel and tray formation
suitably stiffened to prevent distortion. The flanges formed by the
casing sections can be drilled for attachment to adjacent components on
All Hot Water Heating Coils are subject
to an air under water test of 2000 kPa. Where higher working pressures
or extreme temperatures are involved coils can be tested up to 3500 kPa
or twice their working pressure.
Coils with a galvanised steel casing are generally supplied unpainted
but special finishes are available on request.