RECO HX2 Series, Nstallation, Operation And Maintenance Manual

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IOM S
ECTION
4- M
AINTENANCE
HX2 S
ERIES
4 - 6
4.3a HX2 Tube Bundle Inspection and Cleaning
Examine the heat exchanger coil for signs of leaking or scale buildup on the tube surface.
If there is no leaking detected, carefully clean any scale from the coil and prepare the
coil for installation. If leaking is detected, either repair or replace the coil.
Whenever cleaning a tube bundle, do not be use a hammer or chisel on the tubes. If it is
necessary to use scrapers, extreme care should be taken to ensure the tubes are not
score or damaged.
Before it is necessary to apply mechanical means for cleaning, try to clean the unit using
the following methods.
a. Circulate hot water at a reasonably high velocity over the tubes.
b. Spray the exterior of the tubes with a high velocity water jet.
c. Consult with manufacturers of cleaning compounds and chemicals. They will check
the nature of the deposit, recommend the right cleaning compound, and in many
cases can provide equipment and personnel for a complete cleaning job.
d. Do not attempt to clean tubes by blowing steam through individual tubes.
To tighten a loose tube joint, use a suitable roller type tube expander. Do not roll tubes
that are not leaking. Note that double wall tubes are not field repairable.
4.3b HX2 Tube Bundle Installation
If the tube bundle is dismantled for any reason, it should be reassembled using new
gaskets.
a. Remove the old element gaskets and clean gasket surfaces. Install two new
gaskets: one ring gasket between the tubesheet and the shell flange, and one rib
gasket between the tubesheet and the element head.
b. Carefully reinstall the heat exchanger coil and element head in the same orientation that it
was removed. Precede with re-torqueing the bolts that secure the coil to the shell flange.
Pay special attention to the divider on the element head and rib gasket to make sure they
line up with the tubesheet on the heat exchanger coil.
c. Refer to the drawing in Section 4.4 for the proper flange tightening sequence and torque
values. Do not tighten bolts until all gaskets are properly seated.
d. Reconnect the steam lines and condensate return lines to the element head. For
threaded connections, follow the recommendations in this IOM, along with all local
codes and accepted practices regarding the use and type of joint compound or pipe
thread sealer at the joint connections.
e. Follow the startup procedure outlined in Section 3.1 to return the unit to service.
f. Carefully check all connections to verify leak-free operation.