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010.4150.0720 08.21
8.1 GENERAL
The VHX-DR economizer is virtually maintenance free.
Nevertheless, periodic inspections will ensure trouble-free
operation and long equipment life.
A routine physical inspection of the heat transfer core area
will depend on the conditions of temperature and the quality
of combustion within the flue gas stream.
NOTE: Ensure that the combustion source is off and is
cool, and that the economizer is cool before attempting
to inspect or clean the heat exchanger.
With clean exhaust conditions, physical inspection will
be minimal if proper combustion at the heat source is
maintained. The inspection and maintenance procedure can
be performed without dismantling any of the piping or the
stack connections.
8.2 REMOVAL OF HEAT MODULES
The heat module(s) is installed in a slot.
Before removing the module, drain the system of water.
Follow this procedure (See Fig 15):
1. To remove module, disconnect flexible piping from the
the heat module.
2. Remove all bolts from the cover plate.
3. Remove the cover plate, which gives full access to the
heat modules.
4. Slide modules out individually.
8.3 MAINTENANCE
The module has no moving parts or electrical components.
The following should be inspected regularly:
• Operational design conditions for the system being
maintained, and meeting the calculated / design values
(leaving temp., pressure drop).
• Increased pressure drop and decreased thermal
efficiency over time are signs of possible fouling.
• Connections for tightness.
• Gas channels for accumulated dirt.
• Plate surfaces for corrosion.
• Seal and gaskets.
• External components such as valves, dampers and
controls.
8.4 CLEANING
The normally high degree of turbulence in the module gives
a self-cleaning effect in the liquid channels, which reduces
fouling and the build-up of contamination, which can
seriously reduce heat transfer capacity and increase pressure
drop.
Cleaning liquid side
In some applications, the fouling tendency can be very high,
for example with extremely hard water at high temperatures.
Fig 15
Header
Flexible
Connectors Cover
Plate Gasket
Removeable
Heat Modules
Fig 14
8. MAINTENANCE AND TROUBLESHOOTING
