Hubbell Electric Heater Company SLN - Manual (Page 12)

12
ANNUAL INSPECTION
1. Flush tank as follows
a. Shut off power supply.
b. Close valve on hot water outlet piping.
c. Open valve on drain piping.
d. Cold water inlet line pressure will be strong enough to flush sediment from the bottom of the
tank out through the drain. Let water run for 3-4 minutes.
e. Close drain valve.
f. Open hot water valve.
g. Turn power supply ON.
2. Units subject to exterior fouling or scaling should be cleaned periodically. A marked increase in
pressure drop and/or reduction in performance usually indicates cleaning is necessary.
3. To clean the outside of the tubes, remove the heating coil and use either of the following
methods.
a. Spray heating coil with water hose.
b. 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 provide
equipment and personnel for a complete cleaning job.
4. Do not tighten bolts until gasket is properly seated.
5. When tightening bolts in the element head, tighten the bolts in a criss-cross pattern. This will
evenly distribute pressure around the flange, and help prevent warping.