World Leaders in Ultra-Pure Heating
Revision 10
www.heateflex.com
01/17/13
405 E. Santa Clara St.
Arcadia, CA 91006-7218
Tel: (626) 599-8566 Fax: (626) 599-9567
positions on the opposite header but generally follow a pattern where tubes at one position on
one header will match with tubes near that position on the other.
When the matching tube end is located, connect it to a pressure gauge also fitted with a flare
fitting. Apply pressure up to 80 psig then wait a few seconds and observe if the pressure falls
on the gauge. If the tube is filled completely with water, the loss of only a few drops will
cause the pressure to fall sufficiently within a few seconds to be observable.
When a tube is found that will not hold pressure, place a mark on it until you are ready to
install the permanent fixture.
Installing a Permanent Tube Block:
First cut off the flared part of the faulty tube ends and remove the PVDF nuts. Next loosen and
remove the nuts from the stainless pass-through fittings. Then remove the white Goretex
sealant from around the outside of the tubing (if it did not come off with the nut) and push the
tubing down through the stainless fitting into the exchanger. Place a small silicone or other
high-temperature elastomer disk inside of the stainless nut and screw it back on the pass-
through fitting. The two tube fittings on the manifold pipes can be sealed using standard
commercially available (Fluoroware/Galtek) PFA flare fitting caps. Alternatively, if the
silicone disks or PFA caps are not available, the stainless fittings can be removed and replaced
by a 1/4" pipe plug or a short piece of 1/4" PFA tubing can be used to connect the two open
fittings on the pipe headers. This small "bypass" should not affect the exchanger's performance
measurably.
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5.2.2 Repairing a Leaking Fitting
Should either the pass-through or flare fitting develop a leak, it can usually be tightened
slightly to stop the leak. The stainless pass-through fittings can be tightened while the unit is
in operation but any PVDF flare fittings that require tightening should be marked and tightened
when the unit is cool and not under pressure. Never tighten the flare fittings when the unit is
hot as over tightening the fitting can eventually cut clear through the tubing and release hot
D.I. water posing a serious safety hazard.
If tightening the nut on the flare fitting does not stop the leak or completely cuts
through the tubing, simply cut the minimum amount of PFA tubing off the end, re-flare
the tube and reconnect it to the fitting. The hand-held tube-flaring tool which requires
no heating and can easily be used on top of the unit is available from the factory.
If necessary, the stainless pass-through fitting may have to be loosened and the
respective tube pulled up out of the exchanger an amount equal to that cut off of the
tube end to provide enough slack. If the tube will not pull up easily, DO NOT use
force! Remove the nut from the pass-through fitting, pull the tube up and slide the
Goretex seal down the tube or replace it as described below, then re-tighten the
