Trane GSSD Installation Water Loop, Loop Water Applications, Ground Water Applications Open Loop

Installation - Water Loop

Loop Water Applications

It should be noted that there is no me- chanical difference between geother- mal (closed loop) and ground water (open loop) GSSD units. Generally in a closed loop application, there is a percentage of antifreeze in the water. In these applications, the 20 degree F freezestat, along with the 7 psig safety pressure switch may be used. All other applications require the 35 degree F freezestat, along with the 35 psig safe- ty pressure switch.

Ground Water Applications (Open Loop)

Where an existing or proposed well can provide an ample supply of suit- able quality water, open ground water systems may be very efficient. How- ever, there are several potential con- siderations that should be addressed prior to installation of an open loop system:

!A 60 mesh straining device must be placed in the incoming water line. The sand filter/separator helps ensure clean water by removing any particles in the water. Note: A filter/separator should be available from your local dealer.

!Even if plenty of water is available, there needs to be an acceptable way to discharge it after it has passed through the heat pump. A three-ton heat pump is

apt to use one million gallons of water per year. It may be necessary to install a recharge well to return the water to the aquifer. In some soils, this may be difficult to do.

!Water quality must also be acceptable to maintain the integrity and life of the unit. The loop fluid must have minimal suspended solids, and must be non-corrosive to copper or brass. See Table 2 for specifications.

Table 2: Water Supply Requirements

Scaling
Calcium and
magnesium salts	Less than 350 ppm
(total hardness)
Corrosion
pH	7.5-9.5
Hydrogen Sulfide	Less than 1 ppm
Sulfates	Less than 25 ppm
Carbon dioxide	Less than 75 ppm
Chloride	Less than 125 ppm
Total dissolved solids	Less than 1000 ppm
(TDS)
Biological Growth
Iron bacteria	Low
Erosion
Suspended Solids	Low

Ground Water Applications (Closed Loop)

Loop sizing should be done by a qual- ified installer to insure maximized unit performance.

In areas where the ground water tem- perature is 66 degrees F or less, the earth coupling fluid requires at least a

15percent by volume antifreeze solu- tion. Using Table 3, calculate the ap- proximate water volume of the system. Add one gallon to your total as an allowance for water in each heat pump and connection hoses. Check the earth coupling design for the anti- freeze percentage required. MORE IS NOT BETTER-Do no exceed the amount indicated in the design specifi- cations.

Table 3: Water Volume

Volume in Gallons/100 Ft.

Pipe Size	3/4”	1”	1 1/4”	1 1/2”	2”
Volume	3.02	4.73	7.52	9.85	15.4
SDR-11
Volume	2.77	4.49	7.77	10.6	17.4
SCH 40

Use only FULL STRENGTH INHIB-

ITED PROPYLENE GLYCOL OR METHANOL, not solutions which have already been diluted.

Note:

The water quality of the fluid loop should meet the same specifications as in Table 2.

15