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Here's a summary of the bulletin regarding R-32 refrigerant leak mitigation for HVAC systems using electronic accessories:
See attached bulletin for wiring diagrams and the rest of the information.
Purpose:
To inform technicians about safety procedures when R-32 refrigerant is used in HVAC systems with electronic accessories (e.g., zoning systems, EACs, UV lamps, humidifiers).
Key Points:
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RDS (Refrigerant Detection System):
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Detects R-32 leaks inside the indoor unit.
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Shuts off heating, cooling, and fan modes.
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Runs the indoor blower at max CFM to dissipate refrigerant.
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A2L Accessory/Zoning Control (Kit #0230K00007):
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Works with RDS to:
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Open all zone dampers to 100%.
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De-energize potential ignition sources (e.g., EACs, UV lamps, HRVs/ERVs).
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After leak is cleared, restores power and returns zoning control to normal.
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Wiring & Installation:
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NEC requires strain relief for 120V wiring to the Accessory/Zoning Control.
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Control box must be mounted inside a metal enclosure (min. 10” x 8” x 3”).
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Enclosure must accommodate connectors and wiring; cover optional if wiring remains within the control box.
Accessory Connection Guidelines:
| Accessory | Power Connection Instructions | Leak Alarm Behavior |
|---|---|---|
| Electronic Air Cleaner (EAC) | Connect via Accessory/Zoning Control | Power cut during leak |
| UV Lamp | Connect via Accessory/Zoning Control | Power cut during leak |
| HRV/ERV | Connect via Accessory/Zoning Control | Power cut during leak |
| Humidifier | Typically powered via HUM terminals on furnace | Not affected by RDS, zoning control not required |
| Dehumidifier | If tied to ductwork, connect via Accessory/Zoning Control | Power cut during leak |
Alternative Option (No Zoning):
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Use DPDT (Double Pole, Double Throw) relays (Part #0130M00908 or equivalent) if the system has no zoning and only one or two accessories.
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Relay must open circuits during a leak alarm.
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Must match the accessory’s amp rating.
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