Pulsacoil 2000 constant rhythmic buzzing

Hello I was wondering if anybody would be able to advise me on an issue my Pulsacoil 2000 has developed over the last few weeks and hopefully put my mind at ease on a couple of questions.

A few weeks ago it started making an on/off buzzing sound every second, this could last a few mins or a few hours, recently it seems to have started doing it for longer periods, to the stage where some days it seems to be constant!. Having looked around this forum, it would seem that it could be a PCB pump board fault? However, my hot water seems to be working ok at the moment, maybe a little more inconsistent with the temp in the shower some days, but I can still hear the water heating during off-peak times.

Getting anyone out at the moment obviously isn't really an option so my main two questions to try and put my mind at ease are:

1. Is the unit just going to pack up completely soon?
   
2. I'm on Economy 7 so the unit running during peak times can get mega expensive, with this buzzing sound happening a lot during peak times, is going to be using electricity? I've read that it's not a good idea to turn the power off to the unit, however, I may have no choice if it's using electricity in the day. Could I turn it off during the day and then just put it back on at night ready for off-peak?
   

Any help/advice would be greatly appreciated, as this is causing quite a lot of stress at an already stressful time!

Thanks in advance

Might be an issue with the pump speed controller or a sensor. Section 3.4 in this manual explains how to check the diagnostic LED on the pcb. Regards Murray

http://www.gledhill-spares.net/documents/PulsaCoil2000-Iss11.pdf

Thanks, Murray, aprreciate that, I'll take a look.

Been doing it a lot less/not at all over the last week, but then one day was doing it most of the day, very strange.

I'm imagining you have fixed this by now, but the usual cause (for anyone else landing on this thread) is a failing DHW sensor. The PCB LED reports no error but changing the DHW sensor fixes it.

Mike the Boilerman wrote:I'm imagining you have fixed this by now, but the usual cause (for anyone else landing on this thread) is a failing DHW sensor. The PCB LED reports no error but changing the DHW sensor fixes it.

Hi Mike, thanks for this and sorry for the late reply. This initially did seem like it had sorted itself, however over the last few days the buzzing is now constant and there is no hot water at all during off-peak times

Using the boost function does provide hot water. Had an engineer out to look at the issue and they have replaced both of the thermostats as it was cutting out and displaying the fault light when using boost, which is no longer happening, so I can get some hot water. But obviously not sustainable as using boost will cost a fortune.