Closed Loop Applications - Carrier 50YFV Installation, Operation And Maintenance Instructions

R e s i d e n t i a l D i g i t a l P a c k a g e d U n i t s G T- P B S e r i e s - 6 0 H z P u r o n
Closed Loop Heat Pump Applications with Internal Flow Control
Units with internal fl ow control come with built-in variable
speed pumps, an expansion tank, fl ushing ports and a three
way valve (used to fl ush the unit). The variable speed pump is
controlled by the Communicating DXM2 board based on the
difference between the entering and leaving water temperature
(ΔT). For operation outside of the normal entering water
temperature range (50° or 60°F - 110°F for cooling, 30°F-70°F
for heating) the DXM2 controller may automatically adjust
the control ΔT to account for the abnormal entering water
temperatures, maintaining an appropriate fl ow rate for proper
unit operation. The expansion tank helps to maintain constant
loop pressure despite the natural expansion and contraction of
the loop as the seasons and loop temperatures vary.
GT-PB Packaged Digital units with Internal Flow Controller
option are also provided with an expansion tank to help
maintain positive pressure on the complete system through
all seasons.
Pre-Installation
Prior to installation, locate and mark all existing underground
utilities, piping, etc. Install loops for new construction before
sidewalks, patios, driveways, and other construction has
begun. During construction, accurately mark all ground loop
piping on the plot plan as an aid in avoiding potential future
damage to the installation.
Piping Installation
The typical closed loop ground source system is shown in
Figure 12a. All earth loop piping materials should be limited
to polyethylene fusion only for in-ground sections of the
loop. Galvanized or steel fi ttings should not be used at any
time due to their tendency to corrode. All plastic to metal
threaded fi ttings should be avoided due to their potential to
leak in earth coupled applications. A fl anged fi tting should be
substituted. Earth loop temperatures can range between
25 and 110°F [-4 to 43°C]. Flow rates between 2.25 and 3
Chart 2: Internal Variable Speed Flow Controller Maximum Performance
60
50
40
30
20
10
0
0 5 10
Magna Geo 25-140 Pump Curve
15 20 25
Flow (GPM)
Internal Flow Controller
gpm per ton [2.41 to 3.23 l/m per kW] of cooling capacity is
recommended in these applications.
Test individual horizontal loop circuits before backfi lling.
Test vertical U-bends and pond loop assemblies prior to
installation. Pressures of at least 100 psi [689 kPa] should be
used when testing. Do not exceed the pipe pressure rating.
Test entire system when all loops are assembled.
NOTICE! If installing MULTIPLE Internal Variable Speed
Flow Controller units (in parallel) on one loop, please
refer to section 'Multiple Unit Piping and Flushing' (later in
this document).
The following section will help to guide you through fl ushing a
unit with internal fl ow control.
Pressure/Water Ports
The pressure ports built in to the unit are provided as a
means of measuring drop through the unit. The water fl ow
through the unit can be checked by measuring the incoming
water pressure at the supply water pressure port and
subtracting the leaving water pressure at the return water
pressure port. Comparing the pressure differential to the
pressure drop table/fl ow rate in Tables 14a
through 14k in this manual will determine
the fl ow rate through the unit.
GPM Head (ft)
0.0
1.0
2.0
3.0
4.0
5.0
6.0
7.0
8.0
9.0
10.0
11.0
12.0
13.0
14.0
15.0
16.0
17.0
30 35 40
18.0
19.0
20.0
R e v : 4 A p r i l , 1 4
NOTICE!
GPM Head (ft)
44.7 21.0 28.9
22.0 27.8
45.4
23.0 26.7
46.1
24.0 25.6
46.8
25.0 24.5
47.5
26 23.4
47.7
27 22.3
47.1
28 21.3
46.1
29 20.2
45.3
30 19.2
43.9
31 18.2
42.6
32 17.3
41.2
33 16.3
39.9
34 15.4
38.7 35 14.4
36 13.5
37.4
37 12.6
36.1
38 11.7
34.9
33.7
32.5
31.3
30.1
®
11