Page 6 of 24 / IM 407
Figure 5.
Figure 6.
Balancing
Valve With
Close-off
Flexible Hose
With Brass
Pipe Fitting
Supply
Return
Condensate
Isolator Pad
Electrical &
Compressor
Access
Blower
Motor
Access
Note: Condensate drain connection must be minimum of 1" (25mm)
below connection to heat pump.
1
⁄
4
'' Per Foot
(21mm Per Meter)
Optional Cleanout
1
1
⁄
2
"
(38mm)
1
1
⁄
2
"
(38mm)
1. Open all valves to full open position and turn on power
to the conditioners.
2. Set thermostat for “Fan Only” operation by selecting
“Off” at the system switch and “On” at the fan switch. If
“Auto” fan operation were selected, the fan would cycle
with the compressor. Check for proper air delivery.
3. All units have two-speed motors. Reconnect for low
speed operation if necessary.
4. Set thermostat to “Cool.” If the thermostat is an auto-
matic changeover type, simply set the cooling tempera-
ture to the coolest position. On manual changeover
types additionally select “Cool” at the system switch.
Start-up
1. Prior to first operation of any conditioner, the water cir-
culating system must be cleaned and flushed of all con-
struction dirt and debris.
If the conditioners are equipped with water shutoff
valves, either electric or pressure operated, the supply
and return runouts must be connected together at each
conditioner location. This will prevent the introduction of
dirt into the unit. Additionally, pressure operated valves
only open when the compressor is operating.
Figure 7.
2. The system should be filled at the city water makeup con-
nection with all air vents open. After filling, vents should be
closed.
The contractor should start main circulator with pres-
sure reducing valve makeup open. Vents should be
checked in sequence to bleed off any trapped air to
assure circulation through all components of the system.
Power to the heat rejector unit should be off, and the
supplementary heat control set at 80
o
F (27
o
C).
While circulating water, the contractor should check
and repair any leaks in the piping. Drains at the lowest
point(s) in the system should be opened for initial flush
and blow-down, making sure city water fill valves are set
to make up water at the same rate. Check the pressure
gauge at pump suction and manually adjust the makeup
to hold the same positive steady pressure both before and
after opening the drain valves. Flush should continue for
at least two hours, or longer if required, to see clear, clean
drain water.
3. Supplemental heater and circulator pump should be shut
off. All drains and vents should be opened to completely
drain down the system. Short circuited supply and return
runouts should now be connected to the conditioner
supply and return connections. Teflon tape is recom-
mended over pipe dope for pipe thread connections. Use
no sealers at the swivel flare connections of hoses.
4. Trisodium phosphate was formerly recommended as a
cleaning agent during flushing. However, many states
and localities ban the introduction of phosphates into
their sewage systems. The current recommendation is to
simply flush longer with warm 80
o
F (27
o
C) water.
5. Refill the system with clean water. Test the litmus paper
for acidity, and treat as required to leave the water slightly
alkaline (pH 7.5 to 8.5). The specified percentage of
antifreeze may also be added at this time. Use commer-
cial grade antifreeze designed for HVAC systems only. Do
not use automotive grade antifreeze.
6. Set the system control and alarm panel heat add setpoint
to 70
o
F (21
o
C) and the heat rejection setpoint to 85
o
F
(29
o
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 and for air and water balancing.
Cleaning and Flushing System
Note: Do not overtorque fittings. The maximum torque without damage to fittings is 30 foot pounds. If a torque wrench is not available, use as a rule of thumb,
finger-tight plus one quarter turn. Use two wrenches to tighten the union, one to hold the line and one for simultaneous tightening of the nut.
Supply Runout
Return Runout
Mains
Runouts Initially
Connected Together
Rubber Hose
Electrical Access Panel
