Specifications

58 YORK INTERNATIONAL
Condenser
In a condenser, trouble due to fouled tubes is usually
indicated by a steady rise in head pressure, over a pe-
riod of time, accompanied by a steady rise in condens-
ing temperature, and noisy operation. These symptoms
may also be due to foul gas buildup. Purging will re-
move the foul gas revealing the effect of fouling.
TUBE FOULING
Fouling of the tubes can be due to deposits of two types
as follows:
1. Rust or sludge, which finds its way into the tubes
and accumulates there. This material usually does
not build up on the inner tube surfaces as scale, but
does interfere with heat transfer. Rust or sludge can
generally be removed from the tubes by a thorough
brushing process.
2. Scale, due to mineral deposits. These deposits, even
though very thin and scarcely detectable upon physi-
cal inspection, are highly resistant to heat transfer.
They can be removed most effectively by circulating
an acid solution through the tubes.
TUBE CLEANING PROCEDURES
Brush Cleaning of Tube
If the tube fouling consists of dirt and sludge, it can usu-
ally be removed by means of the brushing process. Drain
the water sides of the circuit to be cleaned (cooling wa-
ter or chilled water) remove the heads and thoroughly
clean each tube with a soft bristle bronze brush. DO
NOT USE A STEEL BRISTLE BRUSH. A steel brush
may damage the tubes.
Improved results can be obtained by admitting water
into the tube during the cleaning process. This can be
done by mounting the brush on a suitable length of 1/8"
pipe with a few small holes at the brush end and con-
necting the other end by means of a hose to the water
supply.
The tubes should always be brush cleaned before acid
cleaning.
Acid Cleaning of Tubes
If the tubes are fouled with a hard scale deposit, they
must be acid cleaned. It is important that before acid
cleaning, the tubes be cleaned by the brushing process
described above. If the relatively loose foreign material
is removed before the acid cleaning, the acid solution
will have less material to dissolve and flush from the
tubes with the result that a more satisfactory cleaning
job will be accomplished with a probable saving of time.
COMMERCIAL ACID CLEANING
In many major cities, commercial organizations now of-
fer a specialized service of acid cleaning coolers and
condensers. If acid cleaning is required, YORK recom-
mends the use of this type of organization. The Dow
Industries Service Division of the Dow Chemical Com-
pany, Tulsa, Oklahoma, with branches in principal cities
is one of the most reliable of these companies.
TESTING FOR COOLER AND CONDENSER TUBE
LEAKS
Cooler and condenser tube leaks may result in refriger-
ant leaking into the water circuit, or water leaking into
the shell depending on the pressure levels. If refrigerant
is leaking into the water it can be detected at the liquid
head vents after a period of shutdown. If water is leak-
ing into the refrigerant, frequent purging will be neces-
sary and system capacity and efficiency will drop off
sharply. If a tube is leaking and water has entered the
system, the cooler and condenser should be valved off
trom the rest of the water circuit and drained immedi-
ately to prevent severe rusting and corrosion. If a tube
leak is indicated, the exact location of the leak may be
determined as follows:
1. Allow the system to warm up until a substantial pres-
sure is reached for testing. Dry nitrogen (pressure
not to exceed 12 PSIG) may be admitted to the unit
to increase pressure in the shell. Remove the heads
and listen at each section of tubes for a hissing sound
that would indicate gas leakage. This will assist in
locating the section of tubes to be further investi-
gated. If the probable location of the leaky tubes has
been determined, treat that section in the following
manner (if the location is not definite, all the tubes
will require investigation).
2. Wash off both tube heads and the ends of all tubes
with water.
NOTE: Do not use carbon tetrachloride for this pur-
pose since its fumes give the same flame
discoloration that the refrigerant does.
3. With nitrogen or dry air blow out the tubes to clear
them of traces of refrigerant laden moisture from the
circulation water. As soon as the tubes are clear, a
cork should be driven into each end of the tube. Re-
peat this with all of the other tubes in the suspected
section or if necessary, with all the tubes in the cooler
or condenser. Allow the cooler or condenser to remain
corked up to 12 to 24 hours before proceeding.
Depending upon the amount of leakage, the corks
may blow from the end of a tube, indicating the loca-
tion of the leakage. If not, it will be necessary to make
a very thorough test with the halide torch.
4. After the tubes have been corked for 12 to 24 hours,
it is recommended that two men working at both ends
of the cooler carefully test each tube - one man re-
moving corks at one end and the other at the op-
posite end to remove corks and handle the test torch.
Start with the top row of tubes in the section being
investigated, remove the corks at the ends of one