Crackling noise from trv new boiler installation

[ESB]

Just had a new combi boiler installed on 4 rad system. Crackling noise coming from trv area on 1st rad nearest boiler. This happens only when boiler in central heating mode not hot water. Can go on for quite some time. When stopped and I turn trv in either direction (keep it on full) noise starts again. Bled rads but still there. There didnt appear to be any cold spots in any of the rads anyway. Took trv head off. Jumper is not loose. Tried another trv head. Still same. I didnt have this problem before new boiler fitted. The noise sounds like metal filings jumping about or bubbles popping. Boiler had to be turned off at mains yesterday due to electric socket being fitted on same circuit. When turned all back on came up with temp error - differential between flow and return temp issue. I have the ch flow set at 70 degrees so I waited for boiler to cool down. Set at 60 and bumped up to 70. So far boiler working but noise still there. Could it be air in the pipe from boiler to 1st rad or bits of solder when pipework done that can't get round the elbow up to trv? The system had a chemical flush when new boiler installed with inhibitor and has a Fernox filter. The installer did come back and flushed rad. The noise stopped. As soon as he had left about 15 mins later it started again! Many thanks.

 

[SimonG]

Was the boiler running heating when turned off?

 

[ESB]

Hi Simon.

No but the electrian turned the circuit off before I had a chance to turn the boiler off on the wall switch.

 

[doitmyself]

Does the noise stop if you remove the TRV head?

 

[ESB]

No. Sadly not. The trv is bi directional and on flow pipe. It seems that the noise cuts in as water flow into rad increases. Usually when system been running a while the noise stops. However as soon as trv settings altered or diverter valve switches back to central heating it starts again. Sometimes only for a short time. Rather random. Yesterday as soon as the boiler ch on I turned the valve quickly on and off and this time the crackling stopped at top flow 6. Just turned the heating on with trv still set at 6 and crackling started but stopped quite quickly. It is almost like I freed part of blockage yesterday. A new trv valve was fitted but still same noise!

 

[ESB]

Sometimes when heating switches off there is a quick crackle.

Many thanks

 

[ESB]

I think something is trying to get through trv either debris or micro air bubbles. Could air do this? All the other rads heat up so if major blockage how would this happen?

 

[Sharp Point]

Has an auto bypass been fitted? not all boilers have them built in.

 

[ESB]

It is a Worcester 25i condensating boiler. Hopefully it has an auto bypass. I have just noticed the trv doesnt switch the rad off! I never turn the rad off anyway. I think calibration may be wrong with it as I hear more pressure coming into pipe and rad when it is on say 3 instead of 6 but that may be the free flow of water on 6. Many thanks

 

[ESB]

It does have an auto air vent. Just checked

 

[Gasmk1]

4 rads its a small system pump speed is too high flowing through rads too quick try getting fitter back to balance the system

 

[ShaunCorbs]

Easy to change via the control panel tho

What's the age of the trv ?

 

[ESB]

Thanks for that. They are sending a senior technical chap as had been back once already. I did wonder if it was a balancing issue. It is a very small one bed house. They are coming back end Nov at my request as I will be off work that week. Do you think the force of the flow is causing micro bubbles. Rest of rads no noise at all

 

[ESB]

Easy to change via the control panel tho

What's the age of the trv ?

Trv is one unused B Gas one I had and I asked the installer when came back to fit it but the same

 

[ESB]

4 rads its a small system pump speed is too high flowing through rads too quick try getting fitter back to balance the system

That makes sense as I guess the new boiler working better than the 22 yr old one

 

[ESB]

If water flow turned down to rad (1st one on circuit) via lockshield will this enable more water to get to the other rads? Many thanks

 

[SimonG]

I'd have just swapped out the valve by now.

 

[ESB]

Trv was swapped and still got same noise. Really odd. I thought it wasn't working but I was too impatient! It is working.

 

[ESB]

Just used the hot water and the boiler made a lot of very loud gulping and splashing noises! I think that is air? Central heating was not on. Ran central heating straight afterwatds ok and couldn't replicate the noise. Auto air vent not set or pump needs bleeding? Never ending! It has been in two weeks and made this noise once before but not so much a few days ago when I increased ch temp. The boiler sounds normal again now after that. Will this damage the boiler?

 

[ESB]

The issue was 3 large pieces of solder caught under trv. Installer sorted.

 

[ESB]

The issue was 3 large pieces of solder caught under trv. Installer sorted.

 

[ESB]

As for the gulping noises when condensate emptying installer thinks this is normal and the noise of the condensate running down the pipe could be fixed by having a bigger pipe installed. However as long as there is nothing wrong I can live with it.