Pulsacoil 2000 - buzzing

Hi,

We have a Pulsacoil 2000 in a new-build flat about 4/5 years old. For the past couple of months it has been intermittently but regularly buzzing and it is driving us mad and keeping us awake at night, from what we can tell:

-> There doesn't seem to be a pattern when it happens, or for how long (ranges from 3 short buzzes to 15 or so) or how often (sometimes lasts a few seconds, sometimes goes intermittently for an hour or more at a time during the day or night)
-> There are 2 different buzzing sounds; a quieter one (which to our ears sounds like it may be coming from the top of the system) which is sometimes, but not always, followed by a louder buzzing and gurgling sound (sounds like it may be coming from further down the boiler)
-> There isn't any disruption to hot water

We've just spent £500 with a company to try and get this fixed, who fitted a new Pump and PSC Board and on a return visit a new thermostat when the hot water stopped working after the initial work. We thought the buzzing had gone away for a few days though we weren't around much in the flat to tell, but it's not come back and is just as bad as before!

We're currently trying to get a response from the company but I was just hoping Mike or someone else might be able to shed some more light on what the cause might be as it feels like the company we used don't fully know?

Thanks very much for any help, Becky

Hi Becky,

A new one on me. I doubt you wanted to hear that did you?

I'd need to hear the sound. The DHW sensor makes the board buzz quietly and rhythmically when it fails, and pump failure can cause odd buzzing noises too, but you have a new one already. Gurgling noise is usually associated with the header tank being empty. Have you checked the level in it?

Cheers, Mike

Hi Becky,

Check the header tank has sufficient water in it. Have all electrical connections checked and the contactor inspected. If those do not reveal anything, a site visit is required