CH. Air noises driving me mad. Vented system.

[friendlyaviator]

Hi there, I really hope someone here can help me.

I have an open vented central heating system. Back in Dec 2011 I drained the CH system down, flushed it with clean water, fitted a new radiator to the living room and refilled with cleaner. Around a week later I drained the cleaner out, fitted TRVs on all but one radiator and refilled with inhibitor.

Ever since then I have been getting gurgling, trapped air noises while the CH pump runs when the CH is on. All radiators are filled with water and don't need anymore bleeding since I refilled the system. The pump also trickles water from the centre bleed screw when I undo it. I cannot find any other bleed vents on the system.

I am having no other symptons, all radiators get hot, the boiler cycles fine it's just this trapped air issue. I do not believe it is sucking in air as the radiators never need bleeding and as such I don't think the volume of air in the system is increasing.

I really hope you can help as the noise wakes my Mrs every morning!

Thanks,

Dean

 

[friendlyaviator]

Put in some Fernox boiler noise reducer, does what it says, great at getting rid of gurgling noisy systems

I might just do that. Do I need to drain and refill??

 

[Baxiboy]

Full instructions on the tin!

 

[friendlyaviator]

Full instructions on the tin!

Thanks. I'll give it a go

 

[Goal difference]

Wondering when you first started how dirty / sludgy things were , this may have moved about and settled somewhere else , making filling more problematic

Reading all the conversation that was my thought. The cleaner has loosened the material but without a full flush it has only moved it in the system.

 

[Goal difference]

Pos try cleaner again for a week or so. If you can it may be worth putting a magnetic filter on the return before the boiler to capture any partials the new cleans releases. Try putting a magnet on the copper pipes especially around where the noise is or where pipes join to see if there is a build up of iron oxide sediment anywhere. ( The magnet will stick if there is any build up. It doesn't need much. I have a piece of copper with less than 2mm build up inside and a magnet sticks to it) It sounds like you have cleaned the rads very well but the pipe work can be just as bad where you get turbulent flow, causing small eddies were iron oxide partials can settle. You may have dislodged some of this material but just moved it in the system and not flushed it out. It's only a thought but worth investigating.

 

[zzzjim]

( had a re read -- facts are a bit spread out )

A thought double check where any Olives got changed , for signs of small leaks when system at rest .

May be sucking air .
Still like looking for Gunge with magnet (Goal Difference)

 

[rsr]

Is there an air vent in the boiler you haven't bled?

 

[friendlyaviator]

Sorry for my delay, I've not had any notifications that you guys had replied...strange!

Anyway, since I tightened the draincock as per my photo I've had no annoying noises from the heating. I need to replace the noisey pump and I have a few questions regarding this but I'll open a new thread!

Thanks again,

Dean

 

[zzzjim]

Nice to hear got some progress , did DOC ( drain off cock ) weep a bit when system Off !



( Re: No Notification . Have been some forum changes )
( because things were getting a bit clogged ,just guessing )

 

[friendlyaviator]

Nice to hear got some progress , did DOC ( drain off cock ) weep a bit when system Off !

No strangely. Only when I applied mains pressure.

 

[ringi]

I am fighting the same war at present, our bungalow has the radiators on drops from the loft and the boiler is a long way from the header tank with lot of horizontal pipe work in loft between. Long-term we are likely to change to a sealed system, but I don’t trust the current pipes to cope with a higher pressure without some leaks somewhere and too much of the pipe work is boxed in to make it easy to find and fix any leaks the higher pressure reveals.

Firstly next time you have a system drained down, I think it is worth fitting a filter on the return before the boiler to capture any partials in the water, they don’t cost that much and help to product the boiler. A Filter aid chemical (Sentinel X900) make help getting any sledge into the water so the filter can remove it.

I have just fitted a Spirovent Air separator to our system just after the boiler feed. Hot water can hold less air then colder water, the Spirovent Air separator removes a lot of micro-bubbles of air from the hot water, as the water cools in radiators etc it adsorbs a bit of air. If it works as claimed, after a few weeks the system will be fee of all air pockets and remain so. (Standard bleeding still needed when refilling the system)
3. Jewson are hiring power flushing units for about £50 (in the drain cleaning section of the hire website for some reason!), I am planning on using one in a few weeks after the X400 that I am putting in today has had time to work.

 

[friendlyaviator]

Dear All,

This is still giving me issues sadly.

So far I have discovered the following:-

If I run the central heating with the boiler stat off ie - pump running but only pumping around cold water, I get no gurgling nosies at all.

If I turn the stat on and the boiler starts to heat then the annoying gurgling nosies return.

They seem to originate at the boiler and bubble up towards the bathroom radiator immediately above it. They come and go.

If I shut off the bathroom radiator TRV the noises move to another radiator.

I discovered if I remove all TRV heads from all radiators there is no gurgling noises in any radiator. This would indicate that as the system heats up and certain TRVs shut that somehow air is being sucked in and pumped around.

My pump speed is set on the lowest setting. Could the TRV's shutting own effectively increase the pressure in the system and therefore the vacuum at the other side of the pump and suck air in?

If this is the case how can I slow my pump down more? A resistor or something?

Many thanks,

Dean

 

[Baxiboy]

Did you try the chemical Fernox 'Boiler Noise Reducer'?

 

[friendlyaviator]

Did you try the chemical Fernox 'Boiler Noise Reducer'?

Yeah I tried 3 lots. My input and output to cylinder coil is a little magnetic. Could this contribute?

 

[TBServices]

Yeah I tried 3 lots. My input and output to cylinder coil is a little magnetic. Could this contribute?

No, you have sludge in your pipework.

 

[friendlyaviator]

No, you have sludge in your pipework.

Thats the only place I can find that is magnetic. I have flushed out the system lots until it ran clear.

Are you saying the sludge could be causing my air problem? If so I will drain and cut out offending pipe work to clear it out.

Thanks

 

[Stuart0782]

Could dry pulling rads with water vax I find this often clear air out of systems for me