Chromalox FXTH PN401, Installation & Operation Manual

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INSTALLATION OF HEATER ASSEMBLY IN TANK (cont’d.)
5. Begin lowering heater into tank as per Figure G, Step 1 thru 3
(end manhole) or Figure H, Step 4 thru 7 (center manhole). Once
the heater has touched bottom, use pulling wire (front lifting
cable) to pull heater toward far end of tank.
6. Before lowering back end of heater, visually gage the remaining
length of heater to be laid down, to be certain an equal amount of
clearance is allowed at both ends of tank. Back end of heater is
lowered into place using rear lifting cable. CAUTION: NEVER
USE RISERS TO SUPPORT HEATER TUBES.
7. Where additional heater assemblies are to be installed in the same
manhole, follow same procedure, being careful not to interfere
with risers or cable on the initial heater.
NOTE: In tanks where the configuration does not allow following
the above procedure, or in above ground tanks, ask for Factory rec-
ommendations for installation of heater.
Figure G – Tanks with Manholes Near End
Step 1
Step 2
Step 3
Figure H – Tanks with Center Manhole
Step 4
Step 5
Step 6
Step 7
INSTALLATION OF FXTH TERMINAL HOUSING
A. Position manhole cover adjacent to manhole. Very carefully untie
rope from anchoring point and pass it through (1) manhole gasket,
(2) opening in manhole cover, and (3) terminal housing gasket.
Securely refasten rope to anchoring point. Do not allow riser
end(s) to fall into oil, or permanent damage will result to the
heater. Bolt down manhole cover using a suitable gasket sealant if
required to obtain water-tight seal.
B. Pull riser(s) upward into position next to terminal housing. Wrap
teflon tape on threaded riser connections and fasten into underside
of terminal housing. Unused connections on bottom of housing
will already contain flush plugs. Attach lifting cables to ring on
under side of terminal housing.
C. Bolt terminal housing to manhole cover or manhole cover
adapter, again using suitable gasket cement. If manhole cover is
machined per Figure B, be sure to install copper gasket washers
under bolt heads. Position housing so conduit connections are in
the most convenient position for your particular installation.
Connect all riser leads to terminals, following markers on wires
and terminals referring to wiring diagram Figure J.
D. Install power leads from terminal housing to control center. See
Specifications Table, Page I for amperages to determine wire and
conduit size as determined by the National Electric Code.
E. To install thermostat wells, insert closed end of the well into brass
fitting in bottom of terminal housing. Push well completely to
bottom of tank. A preliminary measurement from manhole level
to tank bottom will aid proper insertion. The well may first hit the
heater. It is then necessary to manipulate the well so that it will
glance off the rounded heater surface and extend to tank bottom.
Mark side of tube at the swage fitting and then pun upward sev-
eral feet to working level. Using a tube cutter, cut the tube at a
point exactly 7” below the mark. Once the tube is cut, be extreme-
ly careful the tube is not allowed to drop through fitting and into
tank. Partially tighten fitting so this cannot happen. Position the
upper end of well 5” off top of tube fitting, then firmly tighten the
fitting. Insert bushing (located in shipping bag inside of terminal
housing) into top of well. This will prevent burrs on tube from
cutting the bulb or capillary of thermostat. Repeat this procedure
until all wells are installed. There can be as many as three wells;
(1) Thermostat, (2) Temperature Indicator, (3) Low Limit Alarm.
F. Install thermostat mounting plate. Make sure thermowells are
aligned with openings in plate and over-temperature leads from
riser are brought through plate. Fasten plate into position.
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