I replaced a Honeywell thermostat with an Aqara thermostat on a heat-pump system. Cooling works, but now when cooling stops the outdoor unit makes a loud “whoosh” sound that I do not remember with the Honeywell.
My wiring is Rc, C, G, Y1, W1, and O/B. I suspect the Aqara may be de-energizing O/B at the same time it turns off Y1, causing the reversing valve to shift or refrigerant pressure to equalize loudly.
Does the Aqara keep O/B energized during cooling idle when “O/B on Cool” is enabled, or does it drop O/B immediately when Y1 stops? Is there a setting or firmware behavior to keep O/B energized after compressor shutdown?
Thank you. Just to confirm, does the current firmware de energize O/B immediately when the cooling call ends? And will the future firmware allow O/B to remain energized during cooling idle or add a delay after compressor shutdown? Is there an estimated timeline or beta firmware?
Thanks again!
I’d be willing to bet money that it’s how your reversing valve is being switched. I’d look into the heat pump configuration inAqara, making sure the O/B settings match what you actually have wired to the pump, then I’d call aqara tech support to make sure it’s functioning as intended by them.
For sure! I ended up switching to another smart thermostat, and the system is now working perfectly. The heat pump shuts off quietly again, with no loud sound.
So in my case, this really seems related to how the Aqara W200 handles the O/B reversing valve at the end of a cooling cycle. I appreciate that Aqara said this may be addressed in a future firmware update but I can’t wait for a hypothetical update while using my HVAC every day.
I may consider going back to Aqara later if this behavior is clearly fixed but for now I had to move on.
Sorry because I otherwise like the Aqara ecosystem.
Hello, I’m also experiencing this same issue with my new W200. Just curious if there’s any idea one when a firmware will be available to resolve this issue? Otherwise I may have to return the W200 and try something else like the OP. Please advise. Thank you so much!
I ended up switching to an Ecobee - I didn’t want to take the risk of damaging my HVAC system. With my old Honeywell thermostat, and now with the Ecobee, the system shuts off normally without that loud noise, so the issue really seems specific to the W200.
Unfortunately, unlike you, I could not return the unit, so I now have an unusable thermostat sitting in a drawer. I originally bought the W200 because I wanted to save some money and get better smart-home functionality, but in the end I spent much more by having to buy another thermostat anyway.
That’s funny, I actually switched to the W200 from an older (~10 year old) Ecobee 3. The Ecobee has been rock solid. I only switched to the W200 because it’s the only thermostat that supports Apples Adaptive Temperature and I wanted to try that out. But with these issues, I’m leaning toward just returning the W200 and going back to ol reliable! Pretty bummed. Sorry to hear you were unable to return yours
Received this response from Aqara Support. Looks like a fix is not going to be ready any time soon. Unfortunately had to return the W200 and go another route. Was looking forward to using this thermostat!
We fully understand your concern that the noise may damage device components, and such worries are completely reasonable.
Let us explain this to you first. When the unit operates in cooling mode and shuts down after reaching the set temperature, the whooshing sound you hear is likely airflow generated by refrigerant pressure equalization between the high-side and low-side sections inside the air conditioner or heat pump the moment the compressor stops. If you notice weakened cooling performance or any other abnormal issues during subsequent use, feel free to contact us anytime.
We have filed a feedback report regarding your situation and plan to release an OTA update to mitigate this noise issue. We highly value user experience, and the OTA update is scheduled to be rolled out within the next two quarters, which will take some time. In the interim, we recommend avoiding setting a cooling temperature that differs drastically from the ambient room temperature; this will reduce pressure differentials upon shutdown and result in a softer, milder noise.
