FT-C Vertical Electric Thermal Fluid Heater Manual 12 2013 ISSUE 1
a) Vent and drain valves should normally be DN15 or DN20 with internal seals made from
materials suited to use with thermal uids. They may be of the screw type if installed on stalks
not less than 300 mm long.
b) Gasketing material specically suited to the task must be used.
c) Drain valves should be tted at all low points in the pipework system and ventilating valves
should be tted at all high points in the installation.
d) Valves must be tted with either the conventional packed stufng box seal or a bellows seal as
required. Where the stufng box is specied, it should be as deep as possible and packed with
Grafoil packing or equal. The valves should have a back seating to allow re-packing without
draining the system.
e) In all units, a “Y” type strainer should be installed in the uid return line, between the
combination tank and the circulating pump. Valves must be provided (unless the heater has
been skid-mounted with the tank) so that the strainer can be isolated for cleaning of the
element. The strainer element should be 60 mesh and must remain in place during normal
operation of the system.
a) All pipework should be constructed from seamless mild steel pipe, conforming to BS EN
10216:2002 or ASTM A106:B, Schedule 40 or equal.
b) Ensure all components exposed to thermal uid ow, including pipe, valves, and screens,
are not copper, copper alloys, bronze, brass, aluminum, or cast iron. Cast iron is porous to
thermal uids, and copper and aluminum act as catalysts in the degradation of some thermal
uids. Carbon or stainless steel, or ductile iron, are recommended.
c) Expansion joints or properly designed and sited loops should be provided to accommodate
thermal expansion. Thermal expansion should be calculated using the maximum possible
utilisation uid temperature, regardless of whether the pipe considered is in the feed
or return circuit. Steel pipe will expand approximately 1 mm. per meter over a 100°C
temperature rise.
d) Supports and anchors must be provided for all pipes where necessary to prevent undue
stresses from being placed on items of equipment, including pumps, valves, and the heater.
Supports and anchors which will not interfere with thermal expansion should be chosen.
e) All pipe joints should be of either welded or anged construction. Screwed joints must be
avoided where possible. In no instance should screwed joints be used in the ow circuit.
f) All anges should be welded to the pipe and not screwed. Flanges should be PN16 or PN25
raised face anges, BS4504.
g) If screwed connections have to be made, e.g., to items of control equipment, use a thread
sealant suitable for use with uids at elevated temperature. Teon tape, standard pipe
sealant, or hemp and paste are not acceptable.
h) Cut screw threads carefully and accurately. If possible, new tools should be used. Threaded
connections larger than 1” are not to be used. It is recommended that GR5 or higher tensile
steel bolts be used for all anged joints.
i) Gasketing material suitable for use with thermal uids at high temperatures should be
used to make all anged joints. Flexible graphite gaskets are suited for most thermal uids.
Recommended gasket thickness is 2.5 - 3 mm.
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