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Mechanical and Electrical Diagrams
6 Mechanical and Electrical Diagrams
6.1 Mechanical Schematic
6.2 Electrical Schematic
Wiring
1.
This drawing shows system wiring concept only. Installer is responsible for all equipment and detailing required by local codes.
2.
All wiring shall be in conformance with the latest edition of the National Electrical Code.
3.
Maximum current rating of Basic Heating Control Relay is 10 Amps, Basic Snow Melting Control Relay is 5 Amps, maximum current rating of Zone Control Relays is 5 Amps, if circulator
draw exceeds this, use pilot relay with 120V AC coil operated by Viega Control.
4.
Consult with control/boiler manufacturer for limitations and installation instructions.
5.
Do not run wires parallel to telephone or power cables. If the sensor wires are located in an area with strong sources of electromagnetic interference (EMI), shielded cable or twisted pair
should be used or the wires can be run in a grounded metal conduit. If using shielded cable, the shield wire should be connected to the Com or Com Sen terminal on the control and not to
earth ground. Use 18 AWG copper wiring for all sensor wiring. Sensors should be located 12" down stream of mixing point.
6.
DHW priority relay must be rated to handle full amperage load of zone circulator relay center.
7.
Other configurations are possible, but all space heating zone circulators must turn off when DHW mode is on or heat source needs to be sized for multiple loads.
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Piping
1.
This drawing shows system piping concept only.
Installer is responsible for all equipment and detailing required by local codes.
2.
Size header piping for maximum flow velocity of 2 feet/second.
3.
All other piping should be sized for a maximum flow velocity of 4 feet/second.
4.
Install a minimum of 12 diameters of straight pipe upstream of all circulators and check valves.
5.
Install isolating flanges or isolating valves on all circulators.
6.
Install purging valve(s) on all circuits.
7.
All closely spaced tees shall be within 4 pipe diameter center to center spacing.
8.
Install minimum of 6 pipe diameters of straight pipe upstream and downstream of all closely spaced tees.
9.
Differential pressure bypass valve prevents flow noise under partial load conditions (some zone valves closed).
10. Set differential pressure bypass valve to delta P of distribution system with all zones open + 1 psi.
11. Not all components may be required depending on control strategy (i.e. constant circulation).
IM-HC 561174 1120 Basic Heating Control
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