Hubbell STH manual

occur at this point, but as the gasket seats, leaking will gradually stop). After leaking has stopped, turn the nut approximately 1 revolution. At this point there may be some miner seepage, wait a few minutes to see if this seepage stops. If seepage continues drain the tank, inspect the manhole ring, and cover for any damage, (repair or replace as required) Repeat the above procedure using a new gasket.

Never try to seal the cover solely by turning the nut down tight this may cut or crush the gasket and make sealing impossible.

16.Drain and flush tank as follows. Perform annually or more often , if required. NOTE: Cement lining is a durable lining that will provide many years of service protecting your steel pressure vessel from corrosion. The process of cement lining includes an inspection to ensure that the lining is applied to the correct thickness, covers all appropriate surfaces, and is free from defects or cracks greater than 3 mm (1/8”) in width. Any deficiencies are repaired at the factory prior to shipment. However, it is characteristic to find hairline cracks in the cement lining prior to initial installation. After the vessel is first filled, the water will work its way into these cracks and begin the corrosion process. At the same time the cement lining undergoes a “wet curing” process whereby the cement absorbs water and expands. The water that is absorbed into the lining becomes trapped between the cement lining and the steel tank and once the cement is fully absorbed with water, the water in contact with the steel tank becomes deoxygenated which serves to protect the steel vessel. In addition, the cement leaches minerals and various impurities from the water which fills and “heals” the cracks. This “healing” together with the “wet curing” and expansion of the cement prevents any ongoing corrosion. In the unlikely event a crack greater than 3 mm (1/8”) develops, the cement lining can be easily repaired in the field. For repair procedures please contact Hubbell

a.Shut down unit as described in Section II.

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.Clean strainer filter, see below.

f.Close drain valve.

g.Open hot water valve.

h.Re-start unit as described in Section II.

17.Clean strainer filter. Perform annually or more often , if required.

a.Remove blowoff bushing (E) or cap (F), as required.

b.Remove gasket (B), if required.

c.Remove, clean, and re-install screen (A).

d.Replace gasket (B).

e.Re-install blowoff bushing (E) or cap (F), as required.

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