Arizona state miner., 1926-05-29
TO REMOVE SCALE
FROM WATER BACKS
Circulation and Heating of
Water Is Retarded.

(Prepared by the United States Department
of Agriculture.)
Hard water causes limy deposit or
scale on the inside Of water backs and
heating coils. If allowed to accumu-
late, the scale retards the circulation
and heating of the water, and, by
closure Of the bore, may prove danger
Gus. Moreover, continued neglect
makes it increasingly difficult to re-
move the scale.
The water back or coil should be
removed from the fire box, says the
United States Department of Agricul-
ture. At the union or other joints
nearest the fire box, discOnnect all
pipes and unscrew them from the wa
ter back. If there is a clamp which
holds the friedrich lining against the
oven, loosen it and remove side and
end Innings. Lift out the water back
and take it out on the ground. Soft
scale or sludge may be removed by
pounding the water back with a mallet
or hammer and then flushing with
strong jet of water. A long gouge or
chiSel Is used on those surfaces that
can be reached. Sometimes the water
back Is heated In blacksmiths forge
and then pounded, but unless carefully
done this treatment may break it,
Some householders keep a spare water
back for use while the other is being
cleaned.
Waters Of varying chemical compo-
sition cause scale differing in compo-
sition and hardness. Ordinary lime
stone calcium carbonate) scale, if
not of excessive thickness, may readily
be removed with muriatic acid. Gyp-
sum calcium Sulphate) scale is hard
and resistant and with other constitu-
ents in their more compact forms is
little affected by muriatic acid The
water back should be laid on the
ground and filled with a strong Solu-
tion of the acid in water. The strength
of the solution should vary with the
amount of deposit, the ordinary mix
ture being one part of acid and five
to seven parts of water. If the de-
pOSit is very thick, the acid needs lit
tie dilution. Commercial muriatic
acid in bottles containing six pounds
(about two and one-half Quarts) costs
20 to 25 cents pound The bottle
should be labeled "Muriatic acid-poi-
son.; and, like other chemicals.
should be kept where children cannot
get 1t. Heating the water back hastens
the action of the acid At the end of
an hour or two, or sooner if the de-
posit is dissolved, pour the solution
from the water back and flush it thor
Oughly with hot water to remove the
acid. If all the deposit has not been
removed, repeat the operation, max
Ing sure that the acid is completely
washed out before replacing the water
back.
Similar methods may be used with
copper coils Place the coil Cor heater)
on two sticks over large bowl With
the aid of lead funnel pour the acid
solution down through the coil. Dip
from the bowl and continue to circu-
late the solution through the coil until
the deposit is dissolved. The coil
should then be thoroughly washed out
with hot water.
The hot-water flow pipe close to a
water back or coil frequently becomes
thickly covered with scale. If the
pipe is brass, it may be disconnected
and treated with acid and then washed
out with hot water. If the pipe is
galvanized iron and in bad condition,
1t will probably be more satisfactory
to replace 1t with new pipe.