Heating system banging like crazy
 

I took my old bathroom out last week ready for a new one being fitted next week. Now every time we put the boiler on it sounds like there is someone running around in the ceiling with a nail gun!

Not sure what I have done wrong but I isolated at the main stop-tap, took the bathroom out, capped off the pipes with push-fit end-stops then slowly turned the water back on. I've checked and bled all radiators and no air seems to be trapped in the central heating system- all radiators spat water out as soon as I turned the local bleed valves.
However, it does seem to make the banging noise when the water is being heated rather than the radiators.
Now my boiler comes on, the pipes bang and move about then the boiler goes off.. Then it comes on again and the same happens. Is there a pump in the boiler pulsing due to trapped air?

Any help and advice would be much appreciated. Hope the boiler isn't knackered!

Thanks

Nick

Is this a continuous knocking sound, or just when the boiler first comes on?

Must be air somewhere , or maybe pump is going too fast.

presumably its not jsut the remaining pipework rattling

I may be completely wrong, but perhaps your old bathroom provided insulation to your heating pipes, and therefore they did not flap about? I don't know, how, though. :wonder: Once you've had the new bathroom fitted, perhaps they will calm down? I hope so.

Heating in my house also makes a right racket for the time it's on. It feels as if the whole house in on a cooker hob at gas mark 6! But I'm gone used to it, now.

Had this at the school where i work. Turned out the heating was up too high. Also, you say you capped the pipes off. Could you try joining the pipes temporarily and see if the noise goes?One last thing, but the off pipes capped will have air in and that may caused water hammer . Seen this at the school too

We really need more details about the type of system you have, ie is it a combi boiler, that being one that heats up the hot water when you turn the tap on, or do you have a hot water cylinder in your airing cupboard? And what, if anything, did you do to the central heating system.

Did you take a radiator off in the bathroom having first drained the system, and then re-fill the system?

If you've got a hot water cylinder (if it's not a combi boiler), you may have emptied the heating coil inside it (it's same water as the central heating) and have air trapped in there.

Water coming out of the bleed valves on the rads doesn't mean there isn't air trapped elsewhere in the system.

It could be your circulating pump has packed up, but let's find out exactly what you've got first.

More details please!

Hi, it's a 25yr old boiler, non-combi. We have a hot water tank in airing cupboard and I can hear that sloshing around everytime the pipes bang.
I'm currently getting hot water by using the immersion to heat the coil in the tank and living without heating tonight as I don't want to cause any damage by running it in it's current state. Yep it's cold here.
I'm betting on it being the pump. Plumber coming over first thing tomorrow.

Will keep you posted.

Thanks

Nick

When mine was making a racket like that it was because the heat exchanger was full of crap and the water inside was boiling. Low flow from a knackered pump didn't help either.

Most likely air is in the system and is trapped in the boiler, heat exchanger. Or you have disturbed some crap in the system and its now causing problems( what colour was the radiator fluid?) lastly by capping off the some pipes you have altered the circuit and water flow is now interupted

Saying that it could be just bad luck/timing and boiler is packing up

I'm betting on trapped air in the heating coil in the cylinder from what you've described. Please let us know what your plumber finds.

Being that old the bathroom radiator is probably on your "primary flow and return" pipes so it came on with your hot water too, taking it out and capping it has probably removed the route to bleed the air from the coil now

I've not removed any radiators. Just the bath, sink and loo.

Otherwise the plumber has sorted it today. It was the pump which draws the water into the tank. Had it replaced and everything now smooth again.

Thanks for your responses.

Cheers

Nick