CGOLDENWALL 100H-M2+S1 Handheld Ultrasonic Flow Meter Flowmeter Clamp on Sensor (DN15-700mm)

For relatively good flows, it works reasonably well (good correlation to Keyence flow sensor). At low floors however, it often reads 0, even though there is a low flow happening through the pipe. The chain straps are also a bit awkward for smaller pipes. It would be nice to have elastic velcro straps for those applications. The signal works mostly if you apply an ultrasound gel on the interface to the pipe. This is not included, I use a clinical ultrasound gel myself.

Three weeks in -----Nice package and tool kit. Initial set up went ok. My first candidates were 1" copper type L pipes on a hot water return circulation loop. I used vaseline. The readings were weird - very low, zero and then they went negative and then positive. My M90 signal strength was not very good. I then got a 'Signal Reverse Error' and an error 0400 and it stopped reading. So I ordered some proper ultrasonic gel; no help. In the interim we replaced the pump (it was old) and when i broke it down we discovered the impeller had no blades on it - hence the negative readings. I sent the vendor all the info and some pix and they got back to me overnight - had me reset to original factory specs and I set everything up again and this time I used the proper gel - they said alway reapply anytime you move it. Worked perfectly. I still get the 'Signal Reverse Error' sometimes if I leave the sensors in place too long on a hot pipe - it dries up. So i add another dab and it works fine again. So far very happy with it.

No calibration certificate included

Funciona muy bien y cumplio con mis expectativas

How do i clear this error code? I got my meter today and it does not work.