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Beckett AquaSmart 7600 Lockout Sensor Error-My Recent Experience and Fix

jmlalley3
jmlalley3 Member Posts: 1
edited August 8 in Thermostats and Controls

Executive Summary: Water on the temperature sensor or in the sensor well will kill a sensor, not just the Beckett Aquasmart Sensor. Make sure your well does not leak as part of troubleshooting this error.

I have a relatively new Buderus Gas Boiler (April 2020) with a Beckett AquaSmart Boiler Temp. Control (120V), Gas w/ Temp. ONLY Sensor (24V Burner Circuit) SKU 7610B0001U. I awoke on a recent Monday morning to no hot water. I discovered that the controller was displaying a "sensor lockout error". I called my HVAC company who arrived in a timely manner. The diagnosis was a bad temp sensor or a bad controller. After some discussion, I opted to start by replacing the temperature sensor. Two hours later, the boiler was up and running. My family was happy although I was feeling quite poor after paying the emergency call out premium.

Four days later, I woke up to no hot water again! The controller was again displaying a "sensor lockout error". I turned power off to the system and went away for 4 days on a planned trip. Upon my return, I powered up and the system ran long enough to make a tank of domestic hot water before getting the "sensor lockout error". I pulled the new sensor out of the well. It looked normal except it was damp. I also noticed a few drops of water in the larger part of the well. I am talking drops, not a leak. If I dried the new sensor out and the well, I could get the boiler to run for 10-15 minutes before getting the “sensor lockout error".

After searching many forums, my only takeaway was that people think the Beckett AquaSmart 7610B is a bad controller and that I should switch to a Hydrolevel. I also contacted Beckett, Buderus (Bosch) and Hydrolevel, all of whom were very responsive and helpful in their own ways. My key takeaway from those exchanges is that a sensor will fail if it gets wet.

Based on that, I ordered a new Beckett sensor and a new well, SKU: 7622TW03U. I removed the old well and discovered that it is different from the new well as shown below. The new one is on the left. The old one is on the right. The black portions on old one (see red arrow) are brittle. I am also able to wiggle the end stub on the old one. My hypothesis is that the seal failed, allowing drops of water to accumulate in the well resulting in prolonged water contact with the sensor causing its failure.

image-13f9f4662673d8-586d.jpeg

I installed a new well and sensor (#3), connected to my existing Beckett Aquasmart controller and am up and running. I will give it a couple of weeks before declaring victory.

In summary, I believe root cause of the original (1) and second (2) sensor failures is that the sensor well started leaking and led to the temperature sensor failures. The Beckett Aquasmart controller did exactly what it is designed to do. The HVAC mechanic installed a new sensor and ignored the wetness of the failed sensor and possible causes. This led to sensor #2 failing in a few days after continued exposure to water. I belive the Beckett Aquasmart controller did what it is designed to do.

If you get the error, look in the well for any signs of water. Do not dismiss dampness or water on the sensor.

Comments welcome.

Cheers

Robert O'Brien

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