Bryant TSTATBBN2S01-C Installationshandbuch PDF herunterladen (Seite 22)

Residential H&V - 60Hz R22 & R410A - Geothermal Heat Pumps - Rev.: 21 Aug, 2007D

GROUND-LOOP HEAT PUMP APPLICATIONS

Table 2: Antifreeze Percentages by Volume

Low Water Temperature Cutout Setting

CXM or DXM Control

When antifreeze is selected, the FP1 jumper (JW3)

should be clipped to select the low temperature

(antifreeze 13°F [-10.6°C]) set point and avoid nuisance

faults (see “Low Water Temperature Cutout Selection” in

this manual). NOTE: Low water temperature operation

requires extended range equipment.

pressure is reached. Open the return valve and a

pressure surge will be sent through the loop to help

purge air pockets from the piping system.

4. Notice the drop in ﬂ uid level in the ﬂ ush cart tank

when the return valve is shut off. If air is adequately

purged from the system, the level will drop only 1-2

inches (2.5 - 5 cm) in a 10” (25 cm) diameter PVC

ﬂ ush tank (about a half gallon [2.3 liters]), since

liquids are incompressible. If the level drops more

than this, ﬂ ushing should continue since air is still

being compressed in the loop ﬂ uid. Perform the “dead

head” procedure a number of times.

Note: This ﬂ uid level drop is your only indication of air in

the loop.

Antifreeze may be added before, during or after the

ﬂ ushing procedure. However, depending upon which time

is chosen, antifreeze could be wasted when emptying the

ﬂ ush cart tank. See antifreeze section for more details.

Loop static pressure will ﬂ uctuate with the seasons.

Pressures will be higher in the winter months than

during the cooling season. This ﬂ uctuation is normal and

should be considered when charging the system initially.

Run the unit in either heating or cooling for a number

of minutes to condition the loop to a homogenous

temperature. This is a good time for tool cleanup, piping

insulation, etc. Then, perform ﬁ nal ﬂ ush and pressurize

the loop to a static pressure of 50-75 psi [345-517 kPa]

(winter) or 35-40 psi [241-276 kPa] (summer). After

pressurization, be sure to loosen the plug at the end of

the Grundfos loop pump motor(s) to allow trapped air to

be discharged and to insure the motor housing has been

ﬂ ooded. This is not required for Taco circulators. Insure

that the Flow Controller provides adequate ﬂ ow through

the unit by checking pressure drop across the heat

exchanger and compare to the pressure drop tables at

the back of the manual.

Antifreeze

In areas where minimum entering loop temperatures drop

below 40°F [5°C] or where piping will be routed through

areas subject to freezing, antifreeze is required. Alcohols

and glycols are commonly used as antifreeze; however

your local sales manager should be consulted for the

antifreeze best suited to your area. Freeze protection

should be maintained to 15°F [9°C] below the lowest

expected entering loop temperature. For example, if

30°F [-1°C] is the minimum expected entering loop

temperature, the leaving loop temperature would be 25 to

22°F [-4 to -6°C] and freeze protection should be at 15°F

[-10°C]. Calculation is as follows:

30°F - 15°F = 15°F [-1°C - 9°C = -10°C].

All alcohols should be premixed and pumped from

a reservoir outside of the building when possible or

introduced under the water level to prevent fumes.

Calculate the total volume of ﬂ uid in the piping system.

Then use the percentage by volume shown in Table

1 for the amount of antifreeze needed. Antifreeze

concentration should be checked from a well mixed

sample using a hydrometer to measure speciﬁ c gravity.

Table 1: Approximate Fluid Volume (gal.)

per 100' of Pipe

Type

Minimum Temperature for Low Temperature Protection

10°F [-12.2°C] 15°F [-9.4°C] 20°F [-6.7°C] 25°F [-3.9°C]

Methanol

100% USP food grade Propylene Glycol

Ethanol*

25%

38%

29%

21%

25%

16%

22%

20%

10%

15%

14%

* Must not be denatured with any petroleum based product

Fluid Volume (gal [liters] per 100’ [30 meters) Pipe)

Pipe Size Volume (gal) [liters]

Copper

1” 4.1 [15.3]

1.25” 6.4 [23.8]

2.5” 9.2 [34.3]

Rubber Hose 1” 3.9 [14.6]

Polyethylene

3/4” IPS SDR11 2.8 [10.4]

1” iPS SDR11 4.5 [16.7]

1.25” IPS SDR11 8.0 [29.8]

1.5” IPS SDR11 10.9 [40.7]

2” IPS SDR11 18.0 [67.0]

1.25” IPS SCH40 8.3 [30.9]

1.5” IPS SCH40 10.9 [40.7]

2” IPS SCH40 17.0 [63.4]

Unit Heat Exchanger Typical 1.0 [3.8]

Flush Cart Tank

10” Dia x 3ft tall

[254mm x 91.4cm tall]

10 [37.9]

1 2 ... 17 18 19 20 21 22 23 24 25 26 27 ... 67 68

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