Problem with heating system - banging noise in hot press

helpmeplease

The expansion vessel (the round red thing) starts to make a loud banging noise every time the heating system comes on. The banging occurs steadily, about every 5-10 seconds.

Can anyone tell me (1) what is wrong? (2) what can I do about it? and (3) is it dangerous?

I am not very knowledgeable about this type of thing.

From googling I have seen suggestions to bleed the radiators but I don't know if this is the right thing to do. If anyone has experience of fixing this I'm open to all advice.

Thanks!

John.G

Oil or gas fired boiler?, if gas fired there may be a pressure gauge in the boiler panel which should read 1 to 1.5 bar with cold boiler and ~ 2/2.5 bar when hot. If no gauge here or if oil fired you should see a flexible filling hose somewhere on the system with a pressure gauge, see if you can locate either of these.

helpmeplease

Thank you for the reply John

John.G wrote: »

Oil or gas fired boiler?, if gas fired there may be a pressure gauge in the boiler panel which should read 1 to 1.5 bar with cold boiler and ~ 2/2.5 bar when hot. If no gauge here or if oil fired you should see a flexible filling hose somewhere on the system with a pressure gauge, see if you can locate either of these.

It's an oil boiler.

I have found the pressure gauge in the hot press.

A few days ago this gauge was actually at 0 and the plumber turned up the pressure for me.

Everything was working fine until last night - the heating came on during the night and the system started to make this banging noise every few seconds. It stops as soon as I switch the heating off.

John.G

helpmeplease wrote: »

Thank you for the reply John



It's an oil boiler.

I have found the pressure gauge in the hot press.

A few days ago this gauge was actually at 0 and the plumber turned up the pressure for me.

Everything was working fine until last night - the heating came on during the night and the system started to make this banging noise every few seconds. It stops as soon as I switch the heating off.

What pressure did he set the pressure to? and what is it now?, if its 0 charge it up to say 1 bar. On the botom/end of the exp vessel you should find a plastic cover, unscrew this and you will will see a (schrader) valve like you have on your car tyres, briefly depress the inside of this with your finger nail and see if either water or air (or nothing) comes out and post back.

helpmeplease

John, I have just come home from work and had another look in the hot press. It seems to be something else entirely that is causing the noise.

There is a device called 'Zone Valve actuator'. There is a black plastic switch that moves from point A to point B. It moves about two thirds of the way over and then makes the banging noise and the switch returns to point A without reaching point B fully.

I'm attaching pics because I'm not sure if I have explained it clearly. As you can probably tell, I don't have any experience with this kind of thing!

Is this difficult to fix myself?

John.G

helpmeplease wrote: »

John, I have just come home from work and had another look in the hot press. It seems to be something else entirely that is causing the noise.

There is a device called 'Zone Valve actuator'. There is a black plastic switch that moves from point A to point B. It moves about two thirds of the way over and then makes the banging noise and the switch returns to point A without reaching point B fully.

I'm attaching pics because I'm not sure if I have explained it clearly. As you can probably tell, I don't have any experience with this kind of thing!

Is this difficult to fix myself?

I would first move this (manual) lever and see can you can move it all the way from A to B, there will be a nice bit of spring resistance but you will soon know if its sticking. The banging noise is a bit strange, it shouldn't make this noise while operating the lever manually. If its not sticking then it could be a number of things including a faulty actuator, you would have to be familiar with a multi tester?? to check out that the power supply isn't being interrupted while its being actuated from the programmed zone. Try operating the lever first.

helpmeplease

John.G wrote: »

I would first move this (manual) lever and see can you can move it all the way from A to B, there will be a nice bit of spring resistance but you will soon know if its sticking. The banging noise is a bit strange, it shouldn't make this noise while operating the lever manually. If its not sticking then it could be a number of things including a faulty actuator, you would have to be familiar with a multi tester?? to check out that the power supply isn't being interrupted while its being actuated from the programmed zone. Try operating the lever first.

The manual lever moves fairly easily; it takes some pressure but it moves smoothly. When I release my finger then the lever returns to the starting position without making the loud banging noise.

The banging noise is only present when the heating is turned on and the lever is moving automatically.

When I move the manual lever, the switch only moves halfway from A to B. It does not reach point B.

I am not familiar with a multi tester.... At this point should I get a plumber??

Really appreciate your help btw

helpmeplease

Also is it dangerous to have the heating on when the valve actuator is operating like this?

The house could do with being warmed up, but I don't want to switch on the heating if there is a risk of damaging the whole system or something like that.

John.G

helpmeplease wrote: »

The manual lever moves fairly easily; it takes some pressure but it moves smoothly. When I release my finger then the lever returns to the starting position without making the loud banging noise.

The banging noise is only present when the heating is turned on and the lever is moving automatically.

When I move the manual lever, the switch only moves halfway from A to B. It does not reach point B.

I am not familiar with a multi tester.... At this point should I get a plumber??

Really appreciate your help btw

Did you move the lever with the actuator still attached to the valve?, in either case once the lever is moved manually to B if you just press it against the side of the actuator then it should stay at B (open position) until is is electrically actuated again, in which case it will close once the signal is switched off.
With the actuator removed can you easily move the "1/4" turn valve shaft?, this should move quite easily, you might just need a pliers but sometimes they will move 90 deg (1/4 turn) back and forth even when only using your fingers.

Just to be clear, if the actuator is still attached to the valve then 2 things should happen when you manually move the lever, the valve should open 90 deg and the boiler should start up if not all ready running.
To check out whether the banging is mechanical or hydraulic carry out the below steps with the valve opened in one test and closed in the second.
Can you identify which zone is being fed by this actuator, if you can, then as a temporary measure you can remove the actuator, open the valve manually 90 deg anti clockwise and just rely on the other zone(s) to switch the boiler on/off...in other words you now just have a "zone" that's all ways on but will only get hot when the boiler is started by one of the other zones.

Edit: Should also have have said that you can obviously start the boiler manually and if no banging with that zone valve opened then its safe IMO, you can also start the boiler with that valve closed, if no banging then open the valve manually and see what happens.

Wearb

It might be wired wrong and circ pump running before valve opens.

helpmeplease

At the risk of sounding completely stupid, it seems the actuator is not connected to the valve. I will attach a pic of the setup. The actuator device has always just been left beside the cylinder and was never attached in the way these devices are attached, for example: https://www.draytoncontrols.co.uk/products/motorised-valves/spares

Pic attached below.

Your advice is so helpful but I'm not that confident in sorting this. I have a friend who is good at this stuff and I will ask him to read your advice and see if we can get anywhere. If not I will call the landlord!!

Thanks a million for your assistance, we're very grateful here!

helpmeplease

Wearb wrote: »

It might be wired wrong and circ pump running before valve opens.

Thanks Wearb

And could this just happen anytime? It had been working well right up until last night, bar a leak in one pipe 2 years ago.

Wearb

helpmeplease wrote: »

Thanks Wearb

And could this just happen anytime? It had been working well right up until last night, bar a leak in one pipe 2 years ago.

The fact it’s not on a valve means my possible cause is not valid.
It might be the motor or gears in the head giving trouble or even a few loose motor mounting screws.

John.G

helpmeplease wrote: »

Thanks Wearb

And could this just happen anytime? It had been working well right up until last night, bar a leak in one pipe 2 years ago.

OK, never mind, back to basics.....if you are up to it just do what I suggested in my post No 4 but INCREASE IT TO 1.5 Bar and post back and we'll take it from there as water or lack of it is probably the problem but once you get that pressure back up to 1.5 bar then you can safely do a bit of trouble shooting.

agusta

With the pressure going to 0.The rads should have been bled to remove air.Sounds like an air in system

John.G

agusta wrote: »

With the pressure going to 0.The rads should have been bled to remove air.Sounds like an air in system

It does, it was OK for few days after his plumber topped it up and only gave trouble last night so if he increases it to 1.5 bar and bleeds the rads he may be OK, also there may not be a AAV fitted at the highest point.

agusta

John.G wrote: »

It does, it was OK for few days after his plumber topped it up and only gave trouble last night so if he increases it to 1.5 bar and bleeds the rads he may be OK, also there may not be a AAV fitted at the highest point.

I agree, Although there is a strong possibility the automatic fill valve is in operation and set to 1 bar to ensure the pressure wont drop to zero again

helpmeplease

John.G wrote: »

OK, never mind, back to basics.....if you are up to it just do what I suggested in my post No 4 but INCREASE IT TO 1.5 Bar and post back and we'll take it from there as water or lack of it is probably the problem but once you get that pressure back up to 1.5 bar then you can safely do a bit of trouble shooting.

agusta wrote: »

With the pressure going to 0.The rads should have been bled to remove air.Sounds like an air in system

John.G wrote: »

It does, it was OK for few days after his plumber topped it up and only gave trouble last night so if he increases it to 1.5 bar and bleeds the rads he may be OK, also there may not be a AAV fitted at the highest point.

agusta wrote: »

I agree, Although there is a strong possibility the automatic fill valve is in operation and set to 1 bar to ensure the pressure wont drop to zero again

Thank you both, I went back to post #4 John and I went looking for the plastic cap to unscrew it. The way it has been installed makes it impossible to get at it properly. I have attached more pics to show you the setup.

Delighted to hear that it might be solved by increasing the pressure and bleeding the rads, I would certainly be confident enough to try that if you think it would help?

jimf

agusta wrote: »

I agree, Although there is a strong possibility the automatic fill valve is in operation and set to 1 bar to ensure the pressure wont drop to zero again

if it is he will need to get it addressed asap fresh water constantly entering the system isn't good for rads or boiler

agusta

looking at the picture in post 18,the auto fill valve in turned off,so all is good

John.G

helpmeplease wrote: »

Thank you both, I went back to post #4 John and I went looking for the plastic cap to unscrew it. The way it has been installed makes it impossible to get at it properly. I have attached more pics to show you the setup.

Delighted to hear that it might be solved by increasing the pressure and bleeding the rads, I would certainly be confident enough to try that if you think it would help?

Yes definitely worth a go, bleed the rads before you fire up the boiler and again while its heating up.
You may not be able to increase that water pressure if the reducing valve has been set to 1 bar but dont worry just ensure that the pressure is kept up after each rad bleed before you fire the boiler.

agusta

The expansion red vessel is ok,no need to worry about that.After bleeding a rad ,check the pressure gauge.To top back up to 1 bar,turn the knob anticlockwise and close again when pressure is at 1 bar

John.G

:P:P

jimf wrote: »

if it is he will need to get it addressed asap fresh water constantly entering the system isn't good for rads or boiler

I reckon the auto fill valve was invented by the radiator manufacturers, almost all the rads in a relations house developed pin holes after 3/4 years, I discovered that one rad connection was only hand tight and was weeping very very slightly. His auto fill valve was open set at 1 bar and as you say the continuous make up of fresh oxygen rich water did the damage.
I pre pressurised his 12 litre exp vessel to 1 bar and gave it a filling pressure of 1.5 bar and then shut off the filling valve, this gave a water reserve of almost 2.5 litres in the expansion vessel. I think some installers just stop filling when the fill pressure is the same as the pre pressure which is normally 1.5 bar. the result is that there is no water reserve whatsoever to make up for any tiny leaks or air venting, people then get fed up with constantly topping up and the "perfect" answer is....the Auto Fill Valve.

jimf

John.G wrote: »

:P:P

I reckon the auto fill valve was invented by the radiator manufacturers, almost all the rads in a relations house developed pin holes after 3/4 years, I discovered that one rad connection was only hand tight and was weeping very very slightly. His auto fill valve was open set at 1 bar and as you say the continuous make up of fresh oxygen rich water did the damage.
I pre pressurised his 12 litre exp vessel to 1 bar and gave it a filling pressure of 1.5 bar and then shut off the filling valve, this gave a water reserve of almost 2.5 litres in the expansion vessel. I think some installers just stop filling when the fill pressure is the same as the pre pressure which is normally 1.5 bar. the result is that there is no water reserve whatsoever to make up for any tiny leaks or air venting, people then get fed up with constantly topping up and the "perfect" answer is....the Auto Fill Valve.

they wer lucky the boiler survived

I have seen a 3yo boiler develop a leak from a like scenario

agusta

jimf wrote: »

they wer lucky the boiler survived

I have seen a 3yo boiler develop a leak from a like scenario

Ive seen it too 24 yer old boiler

John.G

jimf wrote: »

they wer lucky the boiler survived

I have seen a 3yo boiler develop a leak from a like scenario

They were, its a 2006 SE Firebird Heatpac still going strong without missing a beat.

jimf

agusta wrote: »

Ive seen it too 24 yer old boiler

an act of god

helpmeplease

John.G wrote: »

Yes definitely worth a go, bleed the rads before you fire up the boiler and again while its heating up.
You may not be able to increase that water pressure if the reducing valve has been set to 1 bar but dont worry just ensure that the pressure is kept up after each rad bleed before you fire the boiler.

agusta wrote: »

The expansion red vessel is ok,no need to worry about that.After bleeding a rad ,check the pressure gauge.To top back up to 1 bar,turn the knob anticlockwise and close again when pressure is at 1 bar

Thanks Agusta and John - I have bled all the rads and there was a lot of air in two radiators (the rest were fine).The pressure did indeed reduce after bleeding the airlocked rads, so I turned the pressure gauge up again as you advised.

Unfortunately the drayton actuator device is still making the same banging sound when I turn on the heating.

This a short video of what's happening:

https://streamable.com/kx9fl

John.G

helpmeplease wrote: »

Thanks Agusta and John - I have bled all the rads and there was a lot of air in two radiators (the rest were fine).The pressure did indeed reduce after bleeding the airlocked rads, so I turned the pressure gauge up again as you advised.

Unfortunately the drayton actuator device is still making the same banging sound when I turn on the heating.

This a short video of what's happening:

https://streamable.com/kx9fl

If you look at the picture in post 11 you will see that valve to which that pesky actuator was attached, someone obviously removed the actuator. That actuated zone valve was/is feeding the cylinder coil and if you look closely at the valve you can see that its opened ~ 1/2 way (judging by the flats on the valve spindle, that's fine as you will have hot water and it can't rise any higher than the boiler temperature so no safety problems there.
There are a number of ways to disable that actuator (if you are happy to do without zoning on the hot water) If you have a programmed zone system then one of the zones will be hot water and you can disable that zone at the programmer, another way is turn the setting on the cylinder thermostat (this should be attached to the cylinder about 1/3 the way up) to its minimum setting. If neither of these work then if you trace the actuator wiring back to a terminal box and remove one wire ( I think its the white wire but I will check that out when I post this) this wire is switched to live via the programmer (if installed) and then in series through the cylinder thermostat to the actuator.

Edit: Fairly sure its the light brown wire but NOT the orange one.

One other thing, what pressure is the expansion vessel showing when the system is up to full temperature?.

helpmeplease

John.G wrote: »

If you look at the picture in post 11 you will see that valve to which that pesky actuator was attached, someone obviously removed the actuator.

I may be wrong but is it possible it was never attached?
I have tried attaching it to the valve and there physically isn't room to attach it because the pipes sitting in front of the valve are blocking the device from fitting in.

It seems quite strange.

That actuated zone valve was/is feeding the cylinder coil and if you look closely at the valve you can see that its opened ~ 1/2 way (judging by the flats on the valve spindle, that's fine as you will have hot water and it can't rise any higher than the boiler temperature so no safety problems there.
There are a number of ways to disable that actuator (if you are happy to do without zoning on the hot water)

I would definitely be happy to try this, but would this affect the hot water supply?

If you have a programmed zone system

I don;t think it is. There are two mechanical (hope that's the right term) thermostats, one upstairs and one downstairs. It's basically a round dial on the wall. There is no way of digitally programming them. The timer for the heating system is also just a standard round dial where you push in the notches to set the timer.

then one of the zones will be hot water and you can disable that zone at the programmer, another way is turn the setting on the cylinder thermostat (this should be attached to the cylinder about 1/3 the way up) to its minimum setting.

There isn't any thermostat attached to this cylinder at all.

If neither of these work then if you trace the actuator wiring back to a terminal box and remove one wire ( I think its the white wire but I will check that out when I post this) this wire is switched to live via the programmer (if installed) and then in series through the cylinder thermostat to the actuator.

Edit: Fairly sure its the light brown wire but NOT the orange one.

One other thing, what pressure is the expansion vessel showing when the system is up to full temperature?.

I actually haven't been running the system because I wasn't sure if it would damage it. If you think it's fine I will put on the heating now and post back with the pressure reading in a while? Will it be safe?

Thanks so much for the advice

John.G

I would be happy personally to run the system, that actuator/valve may in fact supply the upstairs rads and the cylinder was always unregulated.

IF SO Can you turn the upstairs thermostat to minimum and see is this deenergizes the actuator.

helpmeplease

John.G wrote: »

I would be happy personally to run the system, that actuator/valve may in fact supply the upstairs rads and the cylinder was always unregulated.

I have been running it since the last post. The pressure gauge is rising and is now slightly over 2. It was slightly under 1.5 when I turned the heating on.

Is this as you would expect? Or is it indicating a problem?

I have just seen your edit. I will adjust the thermostat now.

John.G

helpmeplease wrote: »

I have been running it since the last post. The pressure gauge is rising and is now slightly over 2. It was slightly under 1.5 when I turned the heating on.

Is this as you would expect? Or is it indicating a problem?

I have just seen your edit. I will adjust the thermostat now.

As long as it doesn't go above 2.9/3,1 bar. You are/should be still protected as the boiler will have a PRV (safety valve) set to lift at 3.5 bar. Unfortunately, due to the position of the exp vessel you cant check for air/water at the schrader valve, if the vessel is full of water either due to a punctured bladder or no pre pressure (air side) then there will be no where for the expansion to go and that's why the PRV is needed.

helpmeplease

John.G wrote: »

I would be happy personally to run the system, that actuator/valve may in fact supply the upstairs rads and the cylinder was always unregulated.

IF SO Can you turn the upstairs thermostat to minimum and see is this deenergizes the actuator.

Amazing!!! That seems to have done the trick!

I turned off the heating, set the upstairs thermostat to minimum and then I switched the heating on again.

The actuator has not clicked once in the last 10 minutes, and the little switch on the device is not moving anymore. As you could see in the video I posted earlier, it was clicking every 10 seconds or so from the moment the heating system came on.

The pressure is at 2.2 but I will keep checking over the next few hours to see if it moves in either direction.

I really appreciate all of the help John!