banging at boulter camray boiler when heating

[excalibur666]

have a boulter camray compact 50/70 oil based central heating system

water via f/e header tank

got an electric valve and the pump is grundfoss 15/60

about 3 months ago lots of banging whilst boiler running/heating, sounded like kettling at the boiler

rads and water get hot no problem just noise at boiler

system drained down and refilled, with a sentinel descaler and left for a while, water drains clear from boiler and rads - no muck, nor deposits
since emptying and refilling exactly same noise whilst boiler running/heating

no noise if boiler turned off and pump just allowed to, well, pump

have taken out pump and checked, clear

have cleaned the valve

got told by my plumber it was still likely to be scale, used some ferroquest, left in for couple of days before draining down and flushing but still got problem, if anything it gets worse

just had boiler serviced and jets changed etc.... they reckon air locking

if that is the case how do i get rid off the air lock, can listen to the pipe work at boiler end and hear the banging so quite possibly agree and occassionally can let little bits of air from rads but not vast amounts

have checked boiler to see if any bleed points can't find anything, only drain cock on the bottom of the tank

have two air vents by pump and valve located by hot water tank upstairs, they are not closed tight and can't seem to tell if they are doing anything, ie. no air or water comes out

just wondering if air gets in when refilling from header tank

have considered emptying down and back refilling from bottom, thought maybe it is a pressure think, rather than header tank but not sure about this but not sure if this could blow crap into header tank or otherwise cause a problem

have also considered replacing the pump but a bit like bit changing for the sake of it

any suggestions?

 

[Agile]

Ferroquest will have no effect on real limescale. I would not recommend a DIY action as it may not be limescale anyway.

I will assume the "plumber" checked the burner pressure to ensure the power output is correct and not set too high?

You need to see if the pump is really pumping around the system properly.

You cannot look into the pipes but you can get a very good idea from the temperature differential along the pipes.

A professional uses a contact differential digital thermometer but a calibrated hand will give a good indication!

Run the heating for say 15 minutes and see what the temperature on the flow and the return is. If there is an adequate flow then the differential will be about 11°C. If its about right and still kettling then it will be likely to caused by lime scale.

If the differential is much over 15°C then its likely to be a flow problem. You could then turn the pump to setting "3" and see if that improves it. Should be on "2" normally.

Tony Glazier

 

[excalibur666]

Thanks for your reply Tony

when the boiler was serviced and jet changed then gizmoes abounded and all sorts of readings taken

the system, valve and pump about 12yoa and the boiler about 8yoa - up 'til first problem previously been running perfect

read some other posts and earlier had boiler running and pump on with the screw out of the front of it, seems to be spinning ok, don't get much water spitting (dribble at best !!!) out (back of screw black) and it does seem to surge from time to time

like the idea of checking temperature differentials

hmmm, pump has always been set on 3, did get recommended to try slowing it and all that succeeded in doing was seriously effect the time it took for rads to warm up, no difference in banging

since draining and refilling banging is more frequent, perhaps more correlating with pump

have had a chat about powerflushing, if have to, seemed like complex to set up and v expensive

Ferroquest will have no effect on real limescale. I would not recommend a DIY action as it may not be limescale anyway.

I will assume the "plumber" checked the burner pressure to ensure the power output is correct and not set too high?

You need to see if the pump is really pumping around the system properly.

You cannot look into the pipes but you can get a very good idea from the temperature differential along the pipes.

A professional uses a contact differential digital thermometer but a calibrated hand will give a good indication!

Run the heating for say 15 minutes and see what the temperature on the flow and the return is. If there is an adequate flow then the differential will be about 11°C. If its about right and still kettling then it will be likely to caused by lime scale.

If the differential is much over 15°C then its likely to be a flow problem. You could then turn the pump to setting "3" and see if that improves it. Should be on "2" normally.

Tony Glazier

 

[josieg]

Hi - I have a boulter camray compact 15/21 oil based central heating system

just had boiler serviced

lots of banging whilst boiler running/heating, sounded like kettling at the boiler

rads and water get hot no problem just noise at boiler no noise if boiler turned off

Had the thermostat replaced and made no difference

Any suggestions what the problem is or how to fix it

 

[oilman]

Josieg, start your own post. Don't hijack, it causes confusion.

Why are you copying excalibur's no sentences/no capitals/no full stop style? If you want help that's fine, but pleeease put some effort into your posting and make it readable. The help's free, but people aren't likely to struggle with hard to read posts.