Baxi Bermuda 'Boiler Noises'

[tutfut01]

System is:
Baxi Bermuda (13 yrs old)
Piping 30 years old
New Hot water tank
Magnaclean fitted
Spirovent fitted
3 way actuator fitted 2 years old
Grunfoss + pump 6 years old

Heating and Hot Water both work.
The pump appears to be OK, opened the screw on the front and there was vibration inside, and water coming out.
Am not OK with actuator's but both the H/W and C/H are working.

The noise is at the boiler. When it first fires up it is OK but as it starts to run longer it starts to bang. Probably about every 5 seconds until it switches off and then it will start the whole cycle again when it fires up
System is regularly serviced and the water coming out of the rads is clean (I have had the system emptied twice last year when fitting a magnaclean and spirovent), so methinks it probably isn't sludge in the system, but could be wrong.

Cannot think of any other info but would appreciate any pointers or indications of where to look.

Many thanks

 

[namsag]

How long before it starts banging .. an hour?? does it start quicker with just hot water on..... Does it bang more just after timer stops demanding heat or HW or room stat room stat reaches temp

 

[tutfut01]

In response:
If the system fires up it will run for about 2 minutes and then start the banging. Only after about 8 seconds and then after 6 seconds, getting less every time until the system switches off the heat. Then when the heat comes back on it will start again. By on and off I mean by the boiler lighting for a short period, going off and then re-igniting then going off through it's cycle as per the timer/sensor settings.

I will have to have a check on whether it is worse or better with hot water. Will post in the morning when I have had a chance to monitor it.

No it does not get worse when the sensor switches off the heat

I have switched the boiler down to low and this has aleviated the problem slightly.

I forgot to say that the system has no air in it.

George.

 

[reneel]

maybe a bit of scale inside your boiler's heat exchanger, boiler silencer added to your system via header tank may be worth a try.

 

[tutfut01]

Thanks to Reneel, I did consider boiler silencer and as it's being serviced on monday may well add it then. Have you had any experience of using it yourself?

To other post, have been monitoring allday and will post results of what the boiler does tonight.

I also cleaned out the Magnaclean, which when I opened it found to be quite full of deposits and sludge on the magnetic post.

George

 

[tutfut01]

Right, the best set of reading i could get

Both the H/W and the C/H are running.

Boiler switches on

First noise - 2mins 10 secs
Second - 2mins 44 secs
Third - 3mins 55 secs
Fourth - 4mins 40 secs
Fifth - 4mins 55 secs
Sixth - 5mins 3secs
Seventh - 5mins 7 secs
Eigth - 5 mins 10secs

Then the heat switched off.

The general perception is it is worse when the hot water is running as well as the central heating.

Thanks - George

 

[tutfut01]

I think I have solved the problem. My Magnaclean was quite dirty with sludge and I think this was reducing the pressure through the heater exchange unit. Thanks to everyone who posted

George