Bedok older block outdoor unit rocks: sitting on an unlevel base
An older Bedok block had an outdoor unit that rocked visibly every time it started up, worse than it had been in previous years. The reservoir-adjacent estate carries decades of aged mounting hardware across its blocks. An unlevel ledge base is easy to miss until the rocking actually becomes visible.
By Team Snowflake | Reviewed 11 Jul 2026
Case summary
Gree Wall-mounted15 years oldHDBBedok, Singapore
- Concern
- The homeowner worried the compressor itself was developing a serious internal fault that would need a full replacement.
- Found
- The outdoor unit was sitting on an unlevel ledge base, causing it to rock during the harder startup load
- Key check
- Checked the level of the ledge base itself before assuming a compressor fault
- Result
- The rocking stopped completely on every startup after the base was levelled properly a few weeks ago. The homeowner avoided paying for compressor work that the unit never actually needed in the first place.
What we were told
The homeowner said the unit had always rocked slightly, but the movement had grown much more noticeable over the past year, especially right on startup each morning. It still cooled properly once running steadily. The ledge itself had never been re-levelled since the original installation decades ago.
What we checked
We treated the startup-specific rocking as the first lead rather than assuming an internal compressor fault. A genuine fault tends to affect performance throughout the run, not just the first few seconds. Visible rocking tied to startup load usually points at the base the unit is sitting on instead.
The compressor ran smoothly once settled, with no unusual internal noise during steady daily operation.
The ledge base itself had settled slightly unevenly over the decades since the block was built.
The unit's feet were not making even contact with the base across all four corners at all.
The harder startup load was enough to rock the unit visibly on that uneven surface each time.
What we found
Over the decades since the block was built, the concrete ledge had settled slightly unevenly, leaving the outdoor unit's mounting feet without even contact across the whole surface. In calm, steady running, the mismatch barely mattered at all. But the harder mechanical load during startup was enough to rock the unit visibly against the uneven base, before it settled back into place once running speed stabilised a few seconds later.
What fixed it
We levelled the base with proper shims under the unit's feet so all four corners made firm, even contact. We did not recommend any compressor work, since it tested normally once isolated from the mount. We advised checking the base level again at the next few services, since older ledges can continue settling gradually over time.
Outcome
The rocking stopped completely on every startup after the base was levelled properly a few weeks ago. The homeowner avoided paying for compressor work that the unit never actually needed in the first place.
What this case teaches us
Visible rocking on startup often means an unlevel base, not the compressor
- A unit that visibly rocks on startup, rather than throughout the run, often points at how it's actually sitting.
- An unlevel base can develop over years as the ledge itself settles slightly with the building.
- Ask for the base to be checked and levelled before approving any compressor replacement.
Related reading
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