Please help a plumbing novice with a noise issue!

Hello people,
I live in a small house with an electric economy seven water heater in the cupboard of my bedroom. There is no gas in my property at all.
The problem is every morning between around 8.30am and 10a.m (around the time the economy 7 switches off)I get a loud chugging/knocking noise coming from my loft above the boiler. This noise wakes me up every day.
Ive tried changing the thermostat on the water heater and lowering the cut off temperature on it but this hasnt helped. I havent got a clue how to stop this noise and its driving me and the mrs mad!
Im thinking maybe theres air in the pipes but not having any radiators i wouldnt have a clue where to bleed the pipes?
Any advice on this matter would be greatly appreciated.

Kind regards

Jamie

electric economy seven water heater

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Very vague! Could you give as much information as possible about this water heater.
Make
model
size ie capacity in litres.

Perhaps a picture?

The economy 7 would go off a lot earlier than the time stated . Try turning the water off when the noise is present if it stops change the ball valve

spoony1977 said:

... between around 8.30am and 10a.m ... wakes me up every day...

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Night worker or student?



Does anyone else live in the house who might be turning on a tap or flushing a toilet?

Do you have aa Cold Water tank in the loft? And is this in the region of where the noise seems to come from?

Hi thanks for the quick replys.
To answer some of the questions the water heater is a Kesteven Grade 3 with a 144 litre capacity.
The economy seven switches off around 8am and from this time on for about 2 hours the noise is apparent intermitently.
No one else lives in the house who could be flushing toilets.
Yes i believe there is a cold water tank in my loft as this feeds my shower but im not sure if this is where the noise is coming from but it could be that area yes.
I am a night worker which is why i lie in quite late.

Kind regards

pwdavis said:

The economy 7 would go off a lot earlier than the time stated . Try turning the water off when the noise is present if it stops change the ball valve

Click to expand...

Not if the electro/mechanical switch was faulty .......not all are radio controlled

anyone?

I am wondering about a couple of things...

Could it be the water tank in the loft, perhaps the ball-valve moving? This would seem more likely if someone had run a tap or flushed a toilet, and I would have expected you to hear it during the rest of the day as well.

Could it be the water cylinder overheating, and discharging upwards into the tank? Again, you would not normally hear it. Or perhaps an expansion/contraction noise of a pipe that has got very hot while the element was heating, and cracking as it cools?

If you try turning the water heater off one night, does the noise stop?

Does the noise vary with time or with sunlight? E.g. is it later as sunrise is later, or on a cloudy morning compared to a sunny morning? (I am thinking about heat expansion e.g. of a pipe)

Sometimes the thermostats of water heaters fail and the water gets much too hot - does this seem to be happening?

Otherwise, go and sit in the loft one morning, with a torch, and look for any signs of water levels rising in the tanks, or bubbling up through a vent pipe. There will normally be a ring or "tide mark" in the tank at the normal water level, and it will be unusual if the level ever rises above this mark. You might also (if the noise is arising in the loft) be able to track down where it is coming from.

Sorry this is not very helpful, because I haven't really got any sound ideas.