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Maritime Geothermal Ltd.
17-Feb-00
Pressure testing linesets
Using the 6 mm schrader valve supplied on each loop the
installer can again check the pressure on each lineset with his
refrigeration gauge set before releasing the pressure and cut-
ting the loop stubs coming into the basement to the proper
lengths.
Interconnecting tubing
Once the outside loops have been installed it is necessary
to interconnect the "gas" and liquid lines of each loop coming
into the building to its corresponding line on the heat pump.
Each set of two pipes is labeled on the EMDX heat pump as
"loop 1 liquid", "loop 1 vapor", etc. depending on the tonnage
of the heat pump. The larger of the two pipes is the "gas" line
(13 mm OD) while the smaller line is the "liquid" line (9 mm
OD). The dealer must install a 13 mm OD "gas" line from
each of the gas lines on the heat pump to the corresponding
gas lines of each groundloop. Similarly a 9 mm OD "liquid"
line must be run from each heat pump "liquid" line to the cor-
responding liquid line of each groundloop.
Note that there is a transition in size from 9 mm to 13 mm
as the liquid line attaches to the groundloop stub coming into
the basement. A suitable reducing coupling can be purchased
from any refrigeration wholesaler.
The tubing used for this procedure must be refrigeration
tubing (cleaned & dehydrated) suitable for the job. Every ef-
fort must also be made to insure that the tubing does not be-
come 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 lo-
cation ready to make the silver soldered joints. It is very im-
portant to keep a refrigeration system perfectly clean and dry
therefore removing the caps just prior to silver soldering will
insure that the tubing is exposed for a minimal time to the at-
mosphere and the associated moisture contained therein.
Insulating linesets
All tubing inside the basement must be insulated with 9
mm wall armaflex or equivalent insulation to prevent conden-
sation and sweating during winter operation.
Silver soldering linesets
Once all the tubing runs have been routed, insulated and
fastened in place the caps can be removed, couplings applied
(or alternately the tubing can be "swaged") and the joints sil-
ver soldered with 5% silfos.
NORDIC® 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.
Vacuuming system
When silver soldering is finished the entire system should
be pressurized to 700 kPa with dry nitrogen and all joints
made by the installer checked for leaks using soap suds or
some other technique that the installer feels comfortable with.
It is important not to bypass this step since vacuuming the
system with a leak will be impossible and attempting to do so
will introduce moisture to the system making the process take
much longer to vacuum after the leak has been found and re-
paired.
Vacuum the system until the reading on an electronic vac-
uum gauge stays below 500 microns for a period of 5 minutes
after the vacuum pump is shut off and the system sealed.
Charging 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 .5 kg 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
schrader valve.
Hot Water Connections
Connection to the hot water generator feature of the
heat pump is accomplished by teeing into an electric or oil
fired hot water tank with a capacity of 180 litres minimum. A
typical piping diagram is shown elsewhere in this manual. Be
sure to note the position of the check valve and the direction
of water flow.
One should be sure the tank is filled with water and
is under pressure before activating the heat pump to insure
proper lubrication of the circulator pump. Slightly loosen the
copper union on the hot water discharge pipe to allow air to
escape from the system before the unit is started. This step
will make certain that the water circulator is flooded with wa-
ter when it is started. Since the pump is water lubricated,
damage will occur to the pump if it is run dry for even a short
period. The union on the discharge water line may have to be
purged of air several times before good circulation is ob-
tained. A hand placed several feet down the line will sense
when the water is flowing.
The thermostats on the hot water tank should be set
to 38 °C. since the heat pump will transfer energy, via an in-
ternal heat exchanger, from the main internal tank normally
maintained at 45°C. By setting the tank thermostats as de-
scribed, the heat pump will try to keep the tank above the
cut-in point of the electric element settings thus generating
hot water from the heat pump only. During periods of high
demand, the electric elements could energize to help make hot
water.
Safety Controls
The NORDIC® heat pump has two built in safety controls
which are designed to protect the unit from situations which
could damage it.
1. Low pressure control
The low pressure control is designed to shut the unit down
