Designs, materials, weights and performance ratings
are approximate and subject to change without notice.
Visit
armstrong
international.com for up-to-date information.
Armstrong
International
221 Armstrong Blvd., Three Rivers, Michigan, 49093 - USA
Tel. (269) 279-3602 Fax. (269) 279-3130
Page 21 of 44
Heat Exchanger Maintenance:
As needed, based upon water quality
.
Performance: Check temperatures and flow rates against the commissioning data. If there is a noticeable reduction in
heat exchanger capacity, temperature, or an elevated pressure drop across the exchanger, excessive mineral scale or
fouling may be present.
Two scale remediation options are: 1. Manual disassembly, descaling, and cleaning. 2. Clean-in-Place method that
floods the heat exchanger with a descaling solution, such as Rite-Qwik™
Before attempting manual cleaning, confirm that an appropriately sized Digital-Flo
®
heat exchanger gasket kit is on-site.
1. Manual Cleaning by Removing Heat Exchanger Tube Bundle
a. De-energize the Digital-Flo
®
control panel following lockout/tagout procedures. Close the steam inlet following
lockout/tagout procedures, stop recirculation pump(s), close cold water inlet, and close recirc return line - in that
order. Allow the heat exchanger to cool. Drain all liquids from the heat exchanger shell.
b. Remove the two-pass head from the shell of the heat exchanger.
c. Extract the tube bundle from the heat exchanger for inspection and manual cleaning. Gentle mechanical cleaning
or pressure washing may be effective in removing deposits from the tube bundle. Soaking the tube bundle in a
chemical cleaning agent, such as Rite-Qwik™, may expedite the manual cleaning process.
d. If cleaning a single wall tube bundle, remove the floating end cover. Descale and remove any mineral deposits on
the inside surface of end cover.
e. Two-pass head, inlet & outlet tubes, and the internal surface of the heat exchanger shell may also require cleaning
and flushing to remove mineral deposits and sediment.
f. Thoroughly, but gently, clean all mating surfaces of the heat exchanger and two-pass head.
g. Reassemble the tube bundle and heat exchanger using new gaskets and O-rings. Replace any compromised
fasteners with identical new parts.
h. Recommission the water heater following IMPORTANT instructions on page 17.
Preventive Maintenance – continued
If ordering Rite-Qwik™, a minimum of 10 gallons
is recommended. Review the Rite-Qwik™ safety
data sheet before using the solution, and follow
appropriate safety and disposal guidelines.
2. Clean-in-Place (CIP) Method
Armstrong offers a suitable cleaning agent called
Rite-Quik™, a non-hazardous chemical cleaner that
has been proven effective for removing deposits
without damaging or causing deterioration to internal
surfaces the Digital-Flo
®
heater.
Rite-Qwik™ can be pumped directly into the heat
exchanger by using an Armstrong Clean-In-Place
unit, conveniently assembled on a portable hand-cart.
See CIP connections detail on pages 23 and 24.
P/N D42760
Summary of Contents for Digital-Flo DF41540
Page 45: ...Notes...
