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MAINTENANCE
6-12
Figure 6.17
Propane Air Regulator Measuring Taps
6.9 HEAT EXCHANGER INSPECTION AND CLEANING
Inspecting the Heat Exchanger
The water-side of the heating surfaces may be inspected by removal of the top heater head. (See Fig.
6.18). The following gaskets will be needed prior to performing the inspection:
GP-18556 Release Gasket
GP-18532 Shell Gasket
To inspect the heat exchanger watersides:
1. Disconnect the electrical power to the unit.
2. Close the water inlet, outlet, and recirculation shut-off valves to the unit.
3. Open the drain valve carefully while opening the relief valve on the right side of the unit shell to
relieve pressure and allow air into the shell.
CAUTION!
Do not drain the unit without venting the shell! A vacuum in the unit may displace the liner causing serious
damage not covered by warranty.
4. Remove the wing nut from the top center of the shell cap and remove the cap.
5. Remove the nuts and cap screws from the upper head. Remove the upper head and upper head-
liner, (See Fig. 6.18). Remove scale from all shell penetration points and sensors.
6. Inspect and, if necessary, clean the heat exchanger tubes of scale and all gasket surfaces thoroughly
before reassembling the upper head. Refer to heat exchanger cleaning steps on page 6.13. AERCO
recommends that
NEW
gaskets be used when reassembling.
7. Place a shell head gasket on top of the shell ring first, then place the release gasket on top of the
shell head gasket. Align the gasket holes with those in the shell ring.
8. Place the upper head liner on top of the gaskets.
9. Place the upper head on next aligning the holes.