Ebay Customer – Non Concentric Theads

CDMR-M2-21-0240A non concentric threads.

13JUL15: Return Ebay customer (4085neil) emailed that "they screw in one turn and that's it ,I bought these from you before and had no trouble that's why I came back to you knowing they fitted, when I took the one out I got from you they have more of a taper then these ones how can you help cheers neil" RG tested faulty anodes with a fitting which indicates that the threads are not concentric. 17JUL15: Currently waiting for Gang to inform us of the cause of the problem and the steps put in place to prevent re-occurrence. 28AUG15: Gang replied with the following: Re the Incorrect threads on anode plugs: Our report is as follows: 1) After rechecking some left plugs and Mg rods during production and discussing the problem many times, our technicians think that the fault should be caused by the thread on the mg rod not the plug, i.e. the outer thread of the Mg rod and axis of Mg rod are not at the same axis. After assembled the plug on to the mg rod, it showed that the outer thread of the plug and axis of Mg rod are not at the same axis. Since the machining tolerance, some of the thread on mg rod may be more inclined than others. It is means that all of our assembled extruded magnesium rod anodes would be similar. 2) The reason of the fault was found in the anodes for Suburban hot water system only: Since the limit of the inside space of the RV Motor homes and Caravans, the hot water unit is a small water heater, i.e. the inner space of the water tank is small, i.e. the inclusiveness to the Mg rod inclination of the water heater would be small too. So the hot water unit requires the more exact coaxiality for Mg rod and plugs than other type water heaters. 3) Our technicians are designing a checking tool to inspect the inclination of the mg rod thread. We will use it in your Suburban anodes to avoid the similar fault in the future. I will send the photo of the checking tool to you after it to be done. 4) Re the goods in your warehouse: If it is possible, please pick up the fault products by vision before send to your customer and let us know the quantity of fault products. We will replace for you in the future. Refer to Gang email dated 28AUG15 for photos of the checking tool.

Verification –Have we found any more that are not concentric? We are checking each anode before it is sent out, so this CAR will remain open until the current stock is sold. Once we know how many are non-conforming we will inform Gang and he will replace them. 31MAY16: Total of 70 to be replaced. Same issue occurring with CDMR-M2-21-0280A. They are to be replaced as well. At present we are still working through the stock and collecting non-conforming anodes as we go. Will leave open until next order of CDMR-M2-21-240A or CDMR-M2-21-280A are checked and given the OK.
Reported by –Brent Linde
Closed by –Brent Linde
Date closed –August 28, 2015