Lochinvar 000 - 500 Installation And Service Manual page 43

THERMAL EXPANSION
A relief valve which discharges periodically may be due
to thermal expansion in a closed system. A hot water
supply boiler installed in a closed sys tem, such as one
with a backflow preventer or check valve in stalled in
the cold water supply, shall be provided with means to
control expansion. Con tact the water sup pli er or local
plumbing inspector on how to correct this situation.
Do not plug or cap the relief valve discharge!
CATHODIC PROTECTION
Hydrogen gas can be produced in a hot water sys tem
that has not been used for a long period of time
(gen er al ly two weeks or more). Hydrogen gas is
ex treme ly flammable. To prevent the pos si bil i ty of
injury under these conditions, we rec om mend the hot
water faucet be open for several minutes at the kitch en
sink before you use any electrical ap pli ance which is
connected to the hot water sys tem. If hydrogen is
present, there will be an un usu al sound such as air
escaping through the pipe as the hot water begins to
flow. There should be no smoking or open flames near
the faucet at the time it is open.
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