What rules regulate condensate disposal for ductless mini-split systems in Connecticut?
The Connecticut State Building Inspector issued an advisory on September 5th to clarify the requirements for condensate disposal on ductless mini-split systems. This guidance ensures consistent enforcement across all municipalities.
Applicable Codes:
Ductless mini-split systems contain cooling coils and evaporators, so they must comply with the following sections of the 2021 Connecticut State Building Code (CSBC):
- IRC Section M1411.3 – Condensate Disposal
- IRC Section M1411.3.1 – Auxiliary Drain Pans and Secondary Drains
- IPC Section 314.2.3 – Condensate Disposal
- IMC Section 307.2.3 – Condensate Disposal
Key Requirement:
According to these code sections, a secondary drain or auxiliary drain pan is required for each cooling or evaporator coil whenever overflow could damage building components.
Building components include, but are not limited to:
- Electrical or mechanical equipment
- Plumbing systems
- Structural elements (floors, walls, beams, etc.)
Determination Process:
- The local building official must review the proposed installation location.
- If an overflow from the primary drain could damage building components, then compliance with Section M1411.3.1 is mandatory.
Compliance Options:
The IRC allows four approved methods to meet the auxiliary drain and secondary drain requirement.
One of these methods includes installing a water-level detection device that complies with UL 508 to automatically shut off the system if water backs up.
Why It Matters:
Mini-split systems can develop drainage issues (e.g., clogged drain lines, dirty filters, or low refrigerant levels) that may cause water overflow. Secondary drain protection helps prevent property damage from such failures.
In summary:
If the installation location poses any risk of damage from condensate overflow, the system must include a secondary drain or equivalent protection as outlined in Section M1411.3.1 of the IRC and corresponding provisions of the IPC and IMC.