Gas Central Heating Banging

[chrissa1]

In my new rented house which has gas central heating, when the boiler fires up to keep the temperature as per the thermostat, there is a bang which sounds like somebody closing a door loudly upstairs. It happens in roughly half hour (random) intervals.
Is this normal? The boiler was serviced in February.

[janbee]

Could it be air in the system? Have you tried bleeding the radiators?

[chrissa1]

I don't know how to do that but I know a man who does. Thanks janbee.

[anneasquith]

hi chrissa, have you settled nicely into your new house ?

[TonyV]

chriss - not normal ask your landlord to take a look

[chrissa1]

Thaks for asking anne. Yes, it's really lovely and I've got my two year old granddaughter here playing in the sun in the garden.

[AlBags]

Thermal or pressure shock.
You need to find out/listen to identify which pipe or component is banging, then insulate/support it.

[chrissa1]

Albags, your post has just made me wonder if it could have been caused by us switching on the immersion heater, not being sure whether the ch system provided hot water as well. We haven't switched it on for a week now as we've worked out that the ch does supply hot water. There have been no thumps so could this have been the cause/solution?

[AlBags]

Sorry Chris .. just catching up ..
Maybe HW cylinder is moving slightly in area of Imm heater when it gets hot.
Only way is to switch it on .. listen and feel the pipes!

Al.

[Cowtipper]

Its usually air hammer. All the high points in the system should have bleed offs.