Central Heating Noise - pulsing

[SnowyOwl]

I wonder if anyone can help with suggestions on how to solve a strange noise in our central heating system. This seems to have appearred/grown worse in the past few months.

We seem to get a kind of grinding/pulsing noise that slowly grows in intensity over a few minutes and then very quickly dies away to nothing. Comes every 45 minutes or so. Almost sounds like a grinding claxon - and pulsing once a second or so. Very loud when lying in our beds - but almost impossible to trace where it is coming from. When it is happening, no obvious source in teh airing cupboard (pump/cylinder) or garage (boiler). You can hear it sort of from teh radiators - some louder some quieter - especially if you get your ear near them - so I am sure it is somewhere in teh system. On occasion I have hit the downstairs radiator which seems to be buzzing a bit - and the buzzing stops - but not convinced this is really related.

All radiators are hot to the very top. Boiler was serviced in September (and had a new fan). No other obvious creaking noises or banging or anything like that - just this very strange noise in the mornings... System comes on around 4AM - and we notice it say 6:30 - so it is not just on initial warm up...

Is it worth considering getting someone in to do a propoer power flush with Kamco FX2 or would that be a waste of time. Is it worth using a noise reducer like X200 or is that pointless?

HELP - please....

Thanks

 

[Space cat]

The last time I had an unexplained noise roughly matching your description, I traced it to a thermostatic radiator valves which was at the wrong end of the radiator (return instead of flow). Most of the time this made no difference but, when the room temperature was at a critical level, it would sound off like a mini road drill and the noise went all through the house.

 

[SnowyOwl]

Thanks for the suggestion. Don't think it is that, though - as I only have a thermostatic valve on one radiator (en-suite towel radiator) which has been there 4 years - and doesn't seem to be the source of the noise.

 

[SimonCzaban]

Hi SnowyOwl. How long has this problem persisted? Coz over time, a central heating system loses its efficiency and you start to experience problems like strange noises.

 

[SnowyOwl]

I'd say the noise has only been there a few months - 3 at most. Otherwise- the system is red hot and seems pretty efficient. It is quick to get to temperature and radiators red hot - and otherwise quiet... Really odd.

Have turned down teh boiler temperature a fair bit to see if that helps (I think the service engineer who serviced it in September turned it up)...

Any further thoughts...? I am OK to get someone to power-flush the system - but only if it is worthwhile doing.

 

[TicklyT]

Radiators make good sounding boards, and the pipes make good 'speaking tubes' sending any noise in the system around the whole house.

Adjusting that lone TRV when the noise starts, turning the valve fully on or off, will help confirm whether or not it is the root of the problem. At least trying that doesn't cost anything.

Other reasons for odd noises include a poorly configured or poorly maintained open vented system getting badly sludged up and starting to draw air down the vent, expanding pipes creaking as they move against floor joists or each other, missing plastic saddles in radiator mounting brackets, etc, etc.

 

[SnowyOwl]

Thanks - if it is sludged up - will power flushing be worthwhile?