Ideal Classic rattling and banging

[kevin_robson]

I have an ideal classic boiler in my kitchen. It works OK but has recently started really rattling and banging. This is transmitting to the pipes and rattling pipes throughout the whole house.

It sounds to me like the noise a moving part i.e. pump would make if failing. From looking at the manual it would appear that the only moving part would be the fan. Is this likely to be the cause of the problem.

However, it doesn't do it all the time, and it seems to work for quite a while before it does this. Would this lead one to assume it may not be a moving part but a heat related problem?

Is it possible to run the boiler with the cover off so I can see where it is coming from or is this dangerous?

Any other ideas?

 

[namsag]

If pipes and rads are red hot ie a lot hotter than normal then it sounds like your boiler stat has gone as this causing banging through pipes , water in header tank will probably be very hot too

 

[kevin_robson]

Thanks
Difficult to say as we have thermostatic rad valves so once they heat up they shut off. I will check if header tank is hot. Any other diagnostics I can do?

 

[Meldrew's mate]

Check that at least one TRV is either fully open or it's actuator head is removed. As you say the system takes a long time before it starts to bang & crash, this could be warming-up time before the TRVs shut.

Check also the pump is pumping correctly, and that the banging doesn't coincide with the hot water reaching temperature.

MM

 

[kevin_robson]

I have two rads on normal valves and they are both open.

"Check also the pump is pumping correctly, and that the banging doesn't coincide with the hot water reaching temperature"

How can I check when the water is hot?

I can hear the pump in the airing cupboard working so dont think it is that.

Thanks

 

[Meldrew's mate]

Despite the name, boilers are not designed to boil water. If they do they cause banging & crashing noises for several seconds before the noise subsides.

Why would a boiler boil?
1. Lack of water circulation, if the heat energy is not taken away the temperature of the water remaining rises until it boils or the control thermostat cuts-out the flame.
2. The control thermostat has failed, causing the water to overheat and boil. This is almost never going to happen without other symptoms, i.e. the paint "burning" off your radiators.

So we come back to lack of circulation....

...something is not pushing the water through the boiler, or the water is prevented from flowing through the boiler.

You asked how to check if the water is hot. Try turning the HW OFF at the programmer - does the symptom recur?
Turn the HW ON, does it go away until the cylinder stat operates and that route through the HW cylinder is blocked by the valve...

...do you see where this is leading (clue: lack of circulation)

MM

 

[kevin_robson]

OK, maybe I've been approaching this wrong - as it had suddenly started banging my first assumption was something was going wrong in the bolier.


However, the questions you have raised seem to backup up other inconsistancies in the heating system. I've actually got a few previous posts on stuff.

OK. Firstly I tried bleeding the rads and there was a little, if not huge amount of air in there. Air in the rads is a problem in this system and I've never found out why. Various people have looked and not found anything wrong with the setup. I believe the next thing to try is a new pump in case that is introducing it.

Secondly, I've realised over the summer that with the hot water on and CH off, the rads still get warm. My dad is going to fit a new diverter valve next time he is down. However, could this be causing the problems or likely to be something seperate?

As for last night I ran it all night (CH but no water) without problems. Will continue to monitor it and when it occurs I'll play with switching water on and playing about with the pump speed. Its on level 2/3 at moment - I'm assuming 3 would be better? Or not if pump may be introducing air?

 

[kevin_robson]

Can anyone add any more from the further detail I've added?

Cheers