IM 742 / Page 7
Start-up
1 . Open all valves to full open position and turn on power
to the conditioner .-
2 . Set thermostat for “Fan Only” operation by selecting
“Off” at the system switch and “On” at the fan switch . If
“Auto” fan operation is selected, the fan will cycle with
the compressor . Check for proper air delivery .
3 . For those units that have two-speed motors, reconnect
for low speed operation if necessary .
4 . Set thermostat to “Cool .” If the thermostat is an automat-
ic changeover type, simply set the cooling temperature
to the coolest position . On manual changeover types
additionally select “Cool” at the system switch .
Again, many conditioners have time delays which
protect the compressor(s) against short cycling . After
a few minutes of operation, check the discharge grilles
for cool air delivery . Measure the temperature differ-
ence between entering and leaving water . It should be
approximately 1
1
⁄
2
times greater than the heating mode
temperature difference . For example, if the cooling
temperature difference is 15°F (8°C), the heating tem-
perature difference should have been 10°F (5°C) .
Without automatic flow control valves, target a cooling
temperature difference of 10°F to 14°F (5°C to 8°C) .
Adjust the combination shutoff/balancing valve in the
return line to a water flow rate which will result in the
10˚F to 14°F (5°C to 8°C) difference.
5 . Set thermostat to “Heat .” If the thermostat is the auto-
matic changeover type, set system switch to the “Auto”
position and depress the heat setting to the warmest
selection . Some conditioners have built-in time delays
which prevent the compressor from immediately start-
ing . With most control schemes, the fan will start imme-
diately . After a few minutes of compressor operation,
check for warm air delivery at discharge grille . If this is
a “cold building” start-up, leave unit running until return
air to the unit is at least 65°F (18°C) .
Measure the temperature difference between enter-
ing and leaving air and entering and leaving water . With
entering water of 60°F to 80°F (16°C to 27°C), leaving
water should be 6°F to 12°F (3 .3°C to 6 .6°C) cooler,
and the air temperature rise through the machine
should not exceed 35°F (19°C) . If the air tempera-
ture exceeds 35°F (19°C), then the water flow rate is
inadequate .
6 . Check the elevation and cleanliness of the condensate
line . If the air is too dry for sufficient dehumidification,
slowly pour enough water into the condensate pan to
ensure proper drainage .
7 . If the conditioner does not operate, check the following
points:
a . Is supply voltage to the machine compatible?
b . Is thermostat type appropriate?
c . Is thermostat wiring correct?
8 . If the conditioner operates but stops after a brief period:
a . Is there proper airflow? Check for dirty filter, incor-
rect fan rotation (3-phase fan motors only), or incor-
rect ductwork .
b . Is there proper water flow rate within temperature
limits? Check water balancing; backflush unit if dirt-
clogged .
9 . Check for vibrating refrigerant piping, fan wheels, etc .
10 . Do not lubricate the fan motor during the first year of
operation as it is prelubricated at the factory .
11 .
Field supplied relays installed on the input terminals W1, W2,
Y1, Y2 or G may introduce electrical noise. Never install relay
coils in series with the inputs.
5 . Refill the system with clean water . Test the water using
litmus paper for acidity, and treat as required to leave the
water slightly alkaline (pH 7 .5 to 8 .5) . The specified per-
centage of antifreeze may also be added at this time . Use
commercial grade antifreeze designed for HVAC systems
only . Do not use automotive grade antifreeze .
Once the system has been filled with clean water
and antifreeze (if used), precautions should be taken
to protect the system from dirty water conditions . Dirty
water will result in system wide degradation of perfor-
mance and solids may clog valves, strainers, flow regu-
lators, etc . Additionally, the heat exchanger may become
clogged which reduces compressor service life or causes
premature failure .
6 . Set the loop water controller heat add setpoint to 70°F
(21°C) and the heat rejection setpoint to 85°F (29°C) .
Supply power to all motors and start the circulating
pumps . After full flow has been established through all
components including the heat rejector (regardless of
season) and air vented and loop temperatures stabilized,
each of the conditioners will be ready for check, test and
start-up, air balancing, and water balancing .