Troubleshooting Noise and Vibration in Evaporative Coolers
Overview
Customers may report excessive noise or vibration from their evaporative cooler. These issues are often related to airflow restrictions, installation practices, or cooler positioning rather than a mechanical fault. This guide provides practical checks and best practices to assist with diagnosing and resolving these concerns.
Step 1: Confirm Installation Best Practices
- Windows and Exhaust: Ensure adequate openings for airflow. Restricted exhaust can cause pressure build-up and noise.
- Outlet Quantity: Verify there are enough outlets to handle the cooler’s airflow capacity.
- Dropper Installation:
- Ensure the dropper is level and square.
- Do not allow the dropper to sit directly on ceiling joists or beams; use isolation pads or flashing to reduce vibration transfer.
- Diverter Cone: Check that a diverter cone is installed at the bottom of the dropper to assist with air distribution and reduce reverberation.
- Outlet Size: Confirm outlets are correctly sized to allow unrestricted airflow.
- Ductwork:
- Ensure ductwork is correctly sized to prevent vibration caused by restricted airflow.
- Make sure ductwork does not rest on beams or structures that can reverberate as air passes through.
- Cooler Location:
- Avoid mounting coolers directly above living areas, as noise can disturb occupants.
- Ideally, position the cooler centrally on the roof (away from sleeping areas and high-use spaces) so duct runs are approximately equal in length.
- Consider neighbouring residences and potential noise impact—consult with the customer and neighbours if necessary.
Step 2: Verify Outlet Capacity Against Cooler Airflow
Rule: Total outlet airflow must be ≥ cooler airflow @80 Pa.
Typical Outlet Airflows
| Outlet Size | Typical L/s | Notes |
|---|---|---|
| 300 mm | 150–170 | Small rooms |
| 350 mm | 250–300 | Most common |
| 400 mm | 350–400 | Larger rooms |
| 450 mm | 450–500 | High airflow |
| 500 mm | 550–600 | Large open areas |
Procedure:
- Count outlets by size.
- Assign typical L/s per outlet size.
- Total all outlets (sum of outlet L/s).
- Compare total outlet capacity against cooler @80 Pa airflow.
- PASS: Total ≥ @80 Pa airflow
- FAIL: Total < @80 Pa airflow → Add or upsize outlets.
Example:
- System: 6 × 350 mm + 2 × 400 mm
- Total = (6 × 300) + (2 × 400) = 2600 L/s
- LCQ450 @80 Pa = 2570 L/s → PASS
- LCQ550 @80 Pa = 2800 L/s → FAIL → Add or upsize outlets.
Step 3: Reference Cooler Airflow Data (@80 Pa)
| Brand / Series | Model | Airflow @80 Pa (L/s) |
|---|---|---|
| Breezair — EXS Series | EXS160 | 1720 |
| EXS180 | 2070 | |
| EXS200 | 2320 | |
| EXS220 | 2540 | |
| Braemar — LCQ (Paradigm) | LCQ350 | 1890 |
| LCQ450 | 2570 | |
| LCQ550 | 2800 | |
| Braemar — LCQV (SuperStealth) | LCQV250 | 1500 |
| LCQV350 | 1990 | |
| LCQV450 | 2620 | |
| LCQV550 | 3070 | |
| Braemar — LPQV (Ultra Low Profile) | LPQV350 | 2010 |
| LPQV450 | 2390 | |
| LPQV550 | 2850 | |
| Coolair — CPQ Series | CPQ450 | 1570 |
| CPQ700 | 2000 | |
| CPQ850 | 2560 | |
| CPQ1100 | 2710 | |
| Braemar — BMQ Series | BMQ650 | 1380 |
| BMQ850 | 2070 | |
| BMQ1150 | 2390 | |
| RPSI — Commercial Series | RPSI2500 | 2130 |
| RPSI2800 | 2530 |
Additional Notes
- Recalculate outlet totals when upgrading coolers. Older droppers may not suit new models.
- Noise and vibration are often symptoms of airflow imbalance rather than mechanical faults.