Venting the Hydronic Coil

mechanical

Installation requirements

Figure I-MR-3. Attach the changeover sensor to the entering water pipe as shown for changeover to work properly

Figure I-MR-4. Close-up view of the changeover sensor

Figure I-MR-5. Manual coil air vent with set screw

Figure I-MR-6. Manual coil air vent with Shrader fitting

Automatic Electric Heat Lockout Switch Two-pipefan-coil units with auxiliary electric heat have an automatic electric heat lockout switch that disengages the electric heat when hydronic heat enables. If the unit has a factory piping package and electric heat, the factory attaches the switch to the supply water pipe. When the lockout switch detects the supply water temperature above 95°F, it disengages the electric heat. This eliminates electric heat and hydronic heat working simultaneously.

If the fan-coil unit does not have a factory piping package, the switch and coiled lead wires ship inside the piping side end panel. The installer should position the lockout switch on the supply water line of the unit by sliding its spring connector over the pipe. See I-MR-7.

The hydronic coil contains a vent, either manual or automatic, to release air from the unit. This vent is not sufficient for venting the water piping system in the building.

The coil air vent is on the piping side, above the coil connections on the unit. See Figure I-MR-5 and I-MR-6. Perform the following steps to vent the coil after installing the unit.

1.Pressurize the building piping system with water and vent any trapped air at system vents.

2.For units with manual air vents, back the set screw out to expel air from the unit and then re-tighten the set screw.

The automatic air vent should require no adjustment for the coil to vent. However, if the coil does not vent immediately, unscrew the outer portion of the fitting to expel air from the port.

If debris has become trapped in the vent, completely remove the outer portion of the fitting and clean.

Figure I-MR-7. Electric heat lock out switch installed

External Insulating Requirements Insulate and vapor seal surfaces colder than surrounding air dew-point a to prevent unplanned condensation. Trane recommends field-insulation of the following areas to prevent potential condensate problems:

1.Supply and return water piping connections

2.Condensate drain lines and connections

3.Fresh air intake duct connections

4.Discharge duct connections

5.Wall boxes

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