# Channel B downgraded **URL:** \ **Category:** Troubleshooting\ **Created:** [July 7, 2022, 3:28pm UTC](https://community.purpleair.com/t/channel-b-downgraded/1177 "2022-07-07T15:28:16Z")\ **Posts on this page:** 13\ **Page:** 1
**Author:** ![tmcnevin](https://avatars.discourse-cdn.com/v4/letter/t/bb73d2/32.png) [@tmcnevin](https://community.purpleair.com/u/tmcnevin)\ **Post date:** [July 7, 2022, 3:28pm UTC](https://community.purpleair.com/t/channel-b-downgraded/1177/1 "2022-07-07T15:28:16Z")
Map button reads low, time graph appears correct. ![image](https://us1.discourse-cdn.com/flex020/uploads/purpleair/original/1X/52e7f603779a9f32ad5e9311251fa5de4f2cfee9.png) I blew compressed air through the unit displacing some dust, but map appearance has not changed. Any thoughts? What is the recourse if unit has become defective? ---
**Author:** ![tmcnevin](https://avatars.discourse-cdn.com/v4/letter/t/bb73d2/32.png) [@tmcnevin](https://community.purpleair.com/u/tmcnevin)\ **Post date:** [July 7, 2022, 3:33pm UTC](https://community.purpleair.com/t/channel-b-downgraded/1177/2 "2022-07-07T15:33:48Z")
Time graph for unit above, showing more correct PM value, and July 4 fireworks spike. ![image](https://us1.discourse-cdn.com/flex020/uploads/purpleair/original/1X/ac68c10f9540ef2dbd06d66d255a67e10e4b6cea.png) ---
**Author:** ![Ethan](https://sea2.discourse-cdn.com/flex020/user_avatar/community.purpleair.com/ethan/32/177_2.png) [@Ethan](https://community.purpleair.com/u/Ethan)\ **Post date:** [July 7, 2022, 7:11pm UTC](https://community.purpleair.com/t/channel-b-downgraded/1177/3 "2022-07-07T19:11:54Z")
Hi @tmcnevin, it looks like your sensor is reporting a very low confidence score. If you view the two channels for your sensor in the image of the graph you sent, you can see that channel A is showing readings dramatically lower than the readings from channel B. Because of this, your sensor has downgraded channel B and is reporting the other channel on the map. That appears incorrect, so I have switched the downgraded channel to channel A. If you have tried cleaning out the laser counters, you may want to look into laser counter replacement. If you are interested, please send an email to [contact@purpleair.com](mailto:contact@purpleair.com) with your order number. ---
**Author:** ![tmcnevin](https://avatars.discourse-cdn.com/v4/letter/t/bb73d2/32.png) [@tmcnevin](https://community.purpleair.com/u/tmcnevin)\ **Post date:** [July 7, 2022, 11:55pm UTC](https://community.purpleair.com/t/channel-b-downgraded/1177/4 "2022-07-07T23:55:25Z")
Thanks, that helps a bit. Interestingly, the time graph still shows A data as B. What does a counter replacement cost? Can you do one, or does the unit consist of both? ---
**Author:** ![tmcnevin](https://avatars.discourse-cdn.com/v4/letter/t/bb73d2/32.png) [@tmcnevin](https://community.purpleair.com/u/tmcnevin)\ **Post date:** [July 14, 2022, 5:09pm UTC](https://community.purpleair.com/t/channel-b-downgraded/1177/5 "2022-07-14T17:09:12Z")
Was this previously received and has there been any progress on your response? ---
**Author:** ![Ethan](https://sea2.discourse-cdn.com/flex020/user_avatar/community.purpleair.com/ethan/32/177_2.png) [@Ethan](https://community.purpleair.com/u/Ethan)\ **Post date:** [July 14, 2022, 6:17pm UTC](https://community.purpleair.com/t/channel-b-downgraded/1177/6 "2022-07-14T18:17:05Z")
My apologies for the delay, I was out of the office for a short time. Replacement laser counters cost $45 + shipping and can be replaced yourself. The following link will bring you to a video on how to complete that process: [LC ReplacementPA-IISDNew.mp4 - Google Drive](https://drive.google.com/file/d/1zotPRQJSo6nWBlA6PqefCOBg_IyXMPSW/view?usp=sharing). The laser counters come already connected in a pair. ---
**Author:** ![pdnagf](https://sea2.discourse-cdn.com/flex020/user_avatar/community.purpleair.com/pdnagf/32/5879_2.png) [@pdnagf](https://community.purpleair.com/u/pdnagf)\ **Post date:** [July 22, 2022, 8:31pm UTC](https://community.purpleair.com/t/channel-b-downgraded/1177/7 "2022-07-22T20:31:35Z")
I have a similar problem as tmcnevin. Channel A is downgraded (multiplied by 9%) but based on nearby readings, I believe it is acting correctly. Channel B is near Zero - not similar to nearby readings. I have cleaned the openings with compressed air several times. Is there any way to downgrade channel B (not use it) and just use channel A? ![Pajaro Dunes North US EPA PM2.5 AQI 10 Minute Average](https://us1.discourse-cdn.com/flex020/uploads/purpleair/original/1X/1eeb02481c5bf1ef84aeb4df21182fb75dd679aa.png) ---
**Author:** ![tmcnevin](https://avatars.discourse-cdn.com/v4/letter/t/bb73d2/32.png) [@tmcnevin](https://community.purpleair.com/u/tmcnevin)\ **Post date:** [July 24, 2022, 6:11pm UTC](https://community.purpleair.com/t/channel-b-downgraded/1177/8 "2022-07-24T18:11:55Z")
I just acquired a WiFi booster which has a different network ID than what my unit is connected to. How do I change it to the boosted network? ---
**Author:** ![tmcnevin](https://avatars.discourse-cdn.com/v4/letter/t/bb73d2/32.png) [@tmcnevin](https://community.purpleair.com/u/tmcnevin)\ **Post date:** [July 24, 2022, 6:21pm UTC](https://community.purpleair.com/t/channel-b-downgraded/1177/9 "2022-07-24T18:21:24Z")
The video is nice but where do I get the counter? ---
**Author:** ![Ethan](https://sea2.discourse-cdn.com/flex020/user_avatar/community.purpleair.com/ethan/32/177_2.png) [@Ethan](https://community.purpleair.com/u/Ethan)\ **Post date:** [July 25, 2022, 2:45pm UTC](https://community.purpleair.com/t/channel-b-downgraded/1177/10 "2022-07-25T14:45:11Z")
View this article for help resetting the WiFi connection: [Reset the WiFi Network Connection](https://community.purpleair.com/t/reset-the-wifi-network-connection/129). To order laser counters, send an email to [contact@purpleair.com](mailto:contact@purpleair.com) with your inquiry. ---
**Author:** ![pdnagf](https://sea2.discourse-cdn.com/flex020/user_avatar/community.purpleair.com/pdnagf/32/5879_2.png) [@pdnagf](https://community.purpleair.com/u/pdnagf)\ **Post date:** [July 25, 2022, 3:32pm UTC](https://community.purpleair.com/t/channel-b-downgraded/1177/11 "2022-07-25T15:32:05Z")
Thank you, Ethan. I will look at the video link you sent to @tmcnevin in the Channel B downgraded topic and see if replacing the sensors is something I can do. ---
**Author:** ![tmcnevin](https://avatars.discourse-cdn.com/v4/letter/t/bb73d2/32.png) [@tmcnevin](https://community.purpleair.com/u/tmcnevin)\ **Post date:** [July 31, 2022, 6:22pm UTC](https://community.purpleair.com/t/channel-b-downgraded/1177/12 "2022-07-31T18:22:41Z")
I installed a router booster that is half the distance to the sensor as the main router. I think I connected the ssensor to the booster, which has a different name, but the signal still stinks (-76). How do I tell which one the sensor is connected to? ---
**Author:** ![geneder](https://avatars.discourse-cdn.com/v4/letter/g/f19dbf/32.png) [@geneder](https://community.purpleair.com/u/geneder)\ **Post date:** [June 28, 2023, 5:55pm UTC](https://community.purpleair.com/t/channel-b-downgraded/1177/13 "2023-06-28T17:55:34Z")
I had a similar problem with Channel B last week. I followed the cleaning procedure and sensor seems to be working normally now. How do I get the downgrade notification to be reset. Here is the link to my PA-II: > **[Real-Time Air Quality Map | PurpleAir](https://map.purpleair.com/1/mAQI/a10/p604800/cC0?key=5GCLB073AAFNQOJY&select=121305#11/44.7505/-122.9345)** > > Real time measurement of air quality on a public map. Useful to community scientists or air quality professionals alike, PurpleAir sensors are easy to install, requiring only a power outlet and WiFi.