Taco GT Instruction Sheet

SUPERSEDES: March 15, 1983
Plant ID# 001-393

APPLICATION:

The Taco geothermal water flow control valve is an electrically
operated valve for use in water source heat pump systems. It
opens and closes slowly and smoothly in response to the
action of a controlling heating and/or cooling thermostat.

SPECIFICATION DATA:

•24 volts
•0.9 amps. (1.3 max. intermittent)
•Temp. range 34F (1C) min., 240F (116C) max.
•Shut off pressure - 65 psi (448kPa) max.
Model No Size
556-G3, 5101-G3 3/4"
557- 3 1"

INSTALLATION:

1. The valve may be installed in any position except upside down; in other words the power head should not be below the valve.
2. The valve should be installed in a clean water system. Sand or other particles may cause the valve to leak.
CAUTION: Sand or other contaminants can damage the valves internal components and cause it to
fail prematurely. Precautions must be taken to prevent contaminants from damaging the valve.
3. The valve should be installed indoors, GT valves for indoor installation only.
4. Install with the arrow on the valve body pointing in the directlon of water flow.
5. A sweat connection valve should have its power head removed before heating the connections. The valve can be sweat into the line
without further disassembly provided care is taken to prevent overheating. Follow these simple instructions:
(1) Use a torch with a sharp, pointed flame.
(2) Clean surfaces thoroughly and use a good grade of flux.
(3) Use of a solder with a melting point below 600F is recommended
(4) Avoid excessive use of flux.
6. Installation over a drain pan is recommended in locations where a water leak can cause damage.
7. Typical wiring diagram:
IMPORTANT: If the thermostat has a heat anticipator, remove it from the circuit by moving the setting arm all the way over in the lowest
resistance direction (longest cycle) on top of the screw or terminal.
8. Allow about 90 seconds for the valve to fully open or close. The valve avoids water hammer by opening and closing slowly.
Instruction Sheet
Taco GT Flow Control Valve
556-G3, 557-G3 5101-G3
Cv
4 6
6.1 0.4 1.0
7.0 0.3 0.7
F
T

MOUNTING POSITIONS

Pressure Drop Table, PSI

Flow in G.P.M.
8 10 12
1.7 2.7 3.9
1.3 2.0 2.9
IS100-4.4
EFFECTIVE: July 5, 2018
14 16 18
5.3 6.9 8.7
4.0 5.2 6.6