Western Electric 407A-4, Instruction Manual

Page: 43 / 136

by-pass ing too much around an active radiator . For auto­
matic drainage , vent cocks Z l 6 . 1W and Zl6 . 2W must be le�
open. Als o, the cool ing units must b e located far enough
above the water tanks so that the pipes to and from the ra­
diators are adequately pitche d to assure rapid drainage.
Adjustment of
For s implicity, consider the coo ling s ystem as two cir­
cuits in series . The first circuit, in which the water
gathers heat, is thr ough the pumps and vacuum tubes as far
as the c ool ing unit manifold. Normall y, the only adjustment
of this circuit is to throttle the two branches for a min­
imum flow of 10 gallons per minute through the modulating
amplifier branch, us ing valve Z 3W, and for 40 gall ons per
minute thr ough the power ampl ifier branch, us ing valve Z4W.
This adjustment is wholly independent of weather . The s ec­
ond circuit, in which the water loses heat, is thr ough the
cooling-unit radiators . This circuit adj us tment is depend­
ent upon operating efficiency, percentage of modulation, and
weather conditions . The guide is the temperature of the
water be ing returned to the tanks , as indicated by thermom­
eter M3W.
For normal operation, valves should b e s et as follows :
Valves Valves Clos ed
Pump Inlets Z l . lW, Zl . 2W Pump Out let Z2 . 2W or Z 2 . 1W
Pump Outlet Z 2 . 1W or Z 2 . 2W, for
for whichever pump is not
whichever pump is in service .
in s ervice .
Isolating, Z lC
Sockets Z lD, Z 2D, ZlE, Z 2E
Isolating, ZllW, Zl2W
Cooler Inlet Z l4. 1W
Q!'
Z l4. 2W
Cooler Vents Zl6. 1W, Z l6 . 2W
Cooler Outlets Z l 7 . 1W, Zl7. 2W
36
Drain
Waste
Drains
Cooler
Cooler
Z 5W, Z6W.
cocks Z 2C , Z 7W
Z 9W, ZlOW
Inlet Zl4. 2W or Z l4.1W
Drains Zl 5. lW, Z l 5 . 2W