Mechanical Cleaning Procedure; Evaporator Tubes; Water Flow Velocities - York MILLENNIUM YS Manual

Maintenance
ever, a company knowledgeable with the chemical clean-
ing procedure should be contracted or consulted. Fol-
low the chemical cleaning company recommendations
concerning solution cleaning strength and time duration
of the cleaning process.
Serious damage to the condenser
tubes will result if the chemical clean-
ing procedure is improperly applied.
Mechanical tube cleaning must always
follow a chemical cleaning procedure.
When chemical cleaning of the condenser tubes is re-
quired it may be necessary to calculate the internal vol-
ume of the waterside condenser tubes. This informa-
tion is necessary to properly mix the correct concentra-
tion of cleaning solution.
Standard materials of construction for York YS Chiller
condensers is copper tubes and mild carbon steel water
boxes.
The internal volume (waterside) of the condenser can
be calculated as follows:
3
Volume (in ) = N * L * 0.30680 in
Where: N = Number of Condenser Tubes
L = Length of each tube in inches
3
To covert in to gallons, divide the Volume (in
3
in /gallon

MECHANICAL CLEANING PROCEDURE

1. Drain the water from the condenser
2. Remove the water boxes from both ends of the con-
denser. Use proper lifting equipment when remov-
ing the water boxes. Use caution not to damage the
threads on the mounting studs that are welded to the
tube sheet.
3. Select a tube cleaning brush for 5/8 inch I.D copper
condenser tubes. If tubes other than 5/8 inch copper
are used, select a tube cleaning brush that is made
44

EVAPORATOR TUBES

The standard evaporator tubes used in York YSChillers
are internally enhanced copper tubes.
Maintain evaporator water or brine flow rates through
the evaporator tubes that the chiller was designed for.
Refer to the engineering data on the sales order form
for the correct flow rates.
The maximum and minimum water flow velocities are
listed in Table 9.
3
/in
If cleaning of the evaporator tubes is required, follow
the condenser cleaning procedure.
TABLE 9 – WATER FLOW VELOCITIES
3
) by 231
Generally, the water or brine that is circulated through
the evaporator is part of closed loop circuit that is treated
with chemicals to prevent the formation of scale and
debris.
*
for the tube size. Generally, brushes made of hard
plastic or brass bristled wires are preferred for clean-
ing copper tubes.
4. Attach the tube cleaning brush to the end of a clean-
ing machine or cleaning rod.
5. Flush the condenser with clean water to remove the
debris.
6. Replace the water box gasket and reassemble the
water boxes onto the condenser.
If the equipment is located in an un-
heated area that is susceptible to freez-
ing, the water must be drained from
the evaporator to prevent tube dam-
age from freezing.
FLUID
MINIMUM FLUID*
VELOCITY FEET/SEC. 3.33 (1.0)
(METERS/SEC.)
MAXIMUM FLUID
VELOCITY FEET/SEC. 12.0 (3.6)
(METERS/SEC.)
Consult the York Factory Order Form for the specific minimum
velocity based upon the type of brine and concentration being
used.
WATER BRINE
4.5 (1.37)
12.0 (3.6)
YORK INTERNATIONAL