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25 MAY 2009

Page 21

000744MAN-02

LINE SET INTERCONNECT TUBING

Once the outside loops have been installed and run into

the building, the piping to the ports on the unit can be
constructed.  Each line set has a liquid line and a vapour line.
The vapour line is 1/2” (OD) and the liquid line is 1/2” (OD).  For
horizontal loops, both lines are 1/2” (OD), reduce one of the
lines in each line set down to 3/8” (OD) before running the lines
over to the heat pump.  These reduced lines will be the liquid
line for each line set.

Do a final pressure check on each line set and then

remove the pressure and cut the ends off the lines.  The heat
pump has ports labeled Liquid 1 to 5 and Vapour 1 to 5.  Run
each line set over to the designated ports on the heat pump.
Refer to

Diagram 000769CDG

for more information on how to

connect to the heat pump.

The tubing used for this procedure must be refrigeration

tubing (cleaned & dehydrated) suitable for the job. Every effort
must also be made to insure that the tubing does not become
contaminated during installation. We recommend that caps be
placed on the open ends of tubing immediately after cuts are
made and that these caps are only removed after all bends have
been made and the pipe fixed in its permanent location ready to
make the silver soldered joints. It is very important to keep a
refrigeration system perfectly clean and dry. Removing the caps
just prior to silver soldering will ensure minimum exposure to
the humidity in the atmosphere.

PIPE INSULATION

All line set piping inside the structure (between the

structure entry point and the heat pump) should be insulated
with 3/8” thick closed cell pipe insulation  to prevent
condensation and dripping onto floors or walls during the
heating season.   It can be slid onto the capped tubing without
having to slice it down the side.  Ensure that any joints in in the
line sets are accessible for leak testing.

Liquid and Vapour ports and any remaining exposed tubing
should be insulated with 3/8”  thick closed cell pipe insulation
once the silver soldering and pressure testing is complete.
Ensure that all individual pieces of pipe insulation are glued to
each other so there are no air gaps.

SILVER SOLDERING LINE SETS

Once all the line sets have been routed, insulated and

fastened in place, the connections to the heat pump ports can
be made.  Remove the pressure from the heat pump and cut the
ends off of the Liquid and Vapour ports.  Remove the caps from
the line set tubing.  The line sets can be connected to the ports
on the heat pump using couplings, or alternately the tubing can
be "swaged".  The joints should be silver soldered with 5%
silfos.

AMERICAN DREAM Geothermal absolutely requires

that dry nitrogen be bled through the system during all
silver soldering procedures so that no oxidation occurs on
the inside of the copper tubing.

The service ports on the unit

can be used to connect the nitrogen with a refrigeration
manifold.

If necessary, a damp clothe can be wrapped around the

each of the ports to prevent melting the grommet when silver

soldering. Ensure that no water enters any of the ports or
tubing.

PRESSURE TESTING

Once all connections are complete, the system should be

pressure tested to

100PSIG (690kPa)

with dry nitrogen. Check

all joints at the unit and any made in the interconnect tubing for
leaks using soap suds, Spray nine, etc. It is important not to
bypass this step as vacuuming the system with a leak will be
impossible and attempting to do so will introduce moisture into
the system, making the vacuum process take much longer than
if the leak had been found and repaired first.

VACUUMING THE SYSTEM

Remove the pressure from the system and connect the

vacuum pump to the refrigeration manifold. Tighten all hose
connections, open the valves on the manifold and start the
vacuum pump.

Vacuum the system until the reading on an electronic

vacuum gauge remains below 500 microns for a period of 5
minutes after the vacuum pump is shut off and the system
sealed.

CHARGING THE SYSTEM

Once the system has been vacuumed, refrigerant can be

added by weighing in 1/3 of the prescribed refrigerant charge
into the low side of the system. Start the heat pump in the
heating mode and continue to add refrigerant as a liquid at a
rate of no more than 1 lb. per minute until the prescribed charge
is reached.

Alternately, before the machine is started, the entire

charge can be weighed into the system through the high side of
the system.

TABLE 16

shows the typical charge per unit size.

This allows for:



20ft of distance (40ft of pipe) interconnect tubing from

the unit to the wall,



20ft of distance from the wall to the borehole /trench,



a standard loop (100ft borehole or 150ft trench).