TRV4 Crackling as it closes.

[Unklian]

Hi All Again.

Well......I've finally replaced my ancient Glowworm with a Vaillant combi.

All happy except......The Drayton TRV4 in the bathroom has always "crackled" when reaching its temperature. Old boiler and new one.

From what I thought / read up on......I believe its tiny air bubbles being forced through the minute gap, just before it is satisfied.

Despite bleeding and topping up several times, it still persists in doing this.

If I had it changed to the return side, do you think it would stop this noise? My thoughts are......If the water can enter the radiator through a much more open valve, it could then rise quietly to the top of the radiator where I can bleed it out.

It should never get as far as the TRV on the return side so the crackling will stop.

Any thoughts / suggestions please.

Cheers.

Ian.

 

[45yearsagasman]

It's worth a try, but I would suggest waiting for a couple of weeks to allow all the air to vent out before changing the trv position.

 

[Unklian]

The system has been filled for 11 days.

The heating hasn't been used except for the initial bleeding and a couple of bleed / top-ups since.

Its all piped correctly and hasn't needed any topping up with the exception of after the bleeding.

So does the heating system need to run hot for a few days in Autumn / Winter then bled to get the dissolved oxygen / air out of the water?

Presumably, If I isolate all the other rads, it's *simply* a matter of draining the offending rad, swapping the tails / valves, back together. fe-fill & bleed?


Cheers.

Ian.

 

[gavinda]

I think you'll find it's actually the radiator flexing a little as the valve shuts, hence no change with 2 different rads. Annoying but not a fault as such. You could try moving the valve to the opposite end of the rad and see if that helps matters.

 

[Unklian]

I think you'll find it's actually the radiator flexing a little as the valve shuts, hence no change with 2 different rads. Annoying but not a fault as such. You could try moving the valve to the opposite end of the rad and see if that helps matters.

Hi gavinda.

Its definitely bubbles, not creaking.

Very annoying as its the only radiator that does it.
The TRVs are bi-directional and all the others are silent in either direction.

Ian.

 

[Agile]

Do you have inhibitor in the system?

Also do you have TRVs on all rads and no auto bypass valves?

Tony

 

[doitall]

If it hasn't been used how is the air bubbling in the rad. ?

 

[mysteryman]

You need either a bypass, or better, one rad on lockshield valves so there is some heat loss. This is ideally a bathroom radiator.

 

[Unklian]

Do you have inhibitor in the system?

Also do you have TRVs on all rads and no auto bypass valves?

Tony

TRVs on all rads except living room radiator.

Clever thermostat in living room which changes temperatures at
a few different times of day.

Inhibitor in system, I saw the installer pouring it in via the Magnaclean.

Ian.

 

[Unklian]

If it hasn't been used how is the air bubbling in the rad. ?

I just keep "giving it a try".

Run it for about 5 minutes, just for the novelty of it.
Trouble is, with the weather at the moment, I'm having to turn the living room thermostat up to about 24 degrees before the heating comes on.
Don't want to leave it running for any longer as I'm just too hot!

Do you think the air / gas will reduce when winter comes along
and the heating is run "properly"
Is the air possibly because the system hasn't been used much since its initial fill?

Cheers.

Ian.

 

[Unklian]

You need either a bypass, or better, one rad on lockshield valves so there is some heat loss. This is ideally a bathroom radiator.

I *believe* there is an inbuilt bypass on the boiler.

Vaillant Ecotec Pro 28.

Ian.

 

[Agile]

There is a built in bypass but its only designed to protect the boiler and as its adjustable we dont know how its set.

You can run the heating by turning the boiler temperature control to nearly minimum and running the heating for some while.

The air will probably disperse after a few hours of use.

Tony

 

[Unklian]

There is a built in bypass but its only designed to protect the boiler and as its adjustable we dont know how its set.

You can run the heating by turning the boiler temperature control to nearly minimum and running the heating for some while.

The air will probably disperse after a few hours of use.

Tony

Hi Tony / Agile.

Just too late !

I partially drained the system.
Changed the rad tails & TRV to the other side.
Re-filled & bled the system.
Turned the boiler down to 55 degrees and ran for 30 mins. bleeding each rad a couple of times and re-filling as I went.

Hopefully sorted!

On an aside......Is it better to run the boiler (Vaillant Ecotec Pro 28 ) at
the minimum temperature (55) to keep the rooms warm or is it better to run it flat out (75) or vary......(55 Autumn, 75 Winter or between)

We have the tap water at 47 degrees and it seems silly to have the boiler run up to 75 degrees to make it. Is that the best way?

Cheers.

Ian.

 

[Agile]

Best to have the boiler as low as you can and adjust it according to the temperature outside ( Manual weather compensation! ). Then it will condense more and be more efficient.

have you moved the TRV to the flow or return?

Now you will have lost some/much of the inhibitor! You must use the same make to top up.

Tony

 

[Unklian]

TRV is now in return side.

Only lost a little water. About 6 litres.

System only has 6 radiators. I managed to keep them all isolated, only lost the water from the boiler & pipes. I believe the inhibitor will still be up to strength. (I notice you say same make. So they're not all differently badged up same thing then?) Can't mix'n'match like for example Petrol?

Looked at the book of words, he's put in 1 litre of "Calmag".

I'll manually adjust the temperature. I'll keep it at 55 untill there's a nip in the air!

Thanks everybody for the advice.

Ian.