Central Heating issue

notahappycamper

Hi,

We have our heating on in the mornings to heat the water. Then it comes on to heat the radiators. But lately, it will only heat the radiators upstairs but not downstairs if it has been heating the water first. You have to wait an hour or so after it been turned off and then turn just the heat on and it will work! Any ideas? Is there an airlock between upstairs and downstairs? Does the system need to be balanced again? Generally when the rads downstairs don't work there is a "whoosing" of water through the rads upstairs nearest the boiler when it has been initially turned on. The boiler is located upstairs by the way.

Thanks...

notahappycamper

notahappycamper wrote: »

Hi,

We have our heating on in the mornings to heat the water. Then it comes on to heat the radiators. But lately, it will only heat the radiators upstairs but not downstairs if it has been heating the water first. You have to wait an hour or so after it been turned off and then turn just the heat on and it will work! Any ideas? Is there an airlock between upstairs and downstairs? Does the system need to be balanced again? Generally when the rads downstairs don't work there is a "whoosing" of water through the rads upstairs nearest the boiler when it has been initially turned on. The boiler is located upstairs by the way.

Thanks...

Any ideas folks?

oikster

Most definitely air. A system plumbed like this has to be perfect or it will always give bother . The radiators on the lower floor are on a drop system in that either each individual pipe drops to lower level or at least two main pipes do.Air elimination is usually sorted out by automatic air vents or in some cases manually. The whooshing sound you are hearing is air in your pipework and pump. Whether this is a sealed system or an open one it may be best to call a plumber out as getting rid of all the air may take some time and knowhow.You can always have a go yourself but it can be frustrating.

notahappycamper

oikster wrote: »

Most definitely air. A system plumbed like this has to be perfect or it will always give bother . The radiators on the lower floor are on a drop system in that either each individual pipe drops to lower level or at least two main pipes do.Air elimination is usually sorted out by automatic air vents or in some cases manually. The whooshing sound you are hearing is air in your pipework and pump. Whether this is a sealed system or an open one it may be best to call a plumber out as getting rid of all the air may take some time and knowhow.You can always have a go yourself but it can be frustrating.

Plumber was out today. He thinks air is getting into the system continually and possibly through the heat-exchanger? Now one rad needs the bleed valve replaced as the head has been rounded off on it! So I dunno, could it be anything else? The boiler is a Glow Worm Flexicom 30sx. It's only about 3 years old.

sullzz

notahappycamper wrote: »

Plumber was out today. He thinks air is getting into the system continually and possibly through the heat-exchanger? Now one rad needs the bleed valve replaced as the head has been rounded off on it! So I dunno, could it be anything else? The boiler is a Glow Worm Flexicom 30sx. It's only about 3 years old.

Air in through the heat exchanger ? Deffo not !!
I presume your heating is a sealed system is sealed , do you have to repressurise it often or do you have an auto filling valve / pressure reducing valve

notahappycamper

sullzz wrote: »

Air in through the heat exchanger ? Deffo not !!
I presume your heating is a sealed system is sealed , do you have to repressurise it often or do you have an auto filling valve / pressure reducing valve

The pressure is currently 1 bar, although he did say the valve in the hot press for it was not working. I do have to bleed the rads upstairs a good bit - two stay roasting, the other stay 90% warm. How else could air be getting into the system if you need to bleed the rads often? The boiler is upstairs and the rads downstairs don't need to be bled often at all the upstairs ones are the issue. But the problem we have been having recently is that after the heat has been on to heat the water, it then heats the rads and the rads upstairs get hot but downstairs are cold! So, I turn off the heat altogether and wait then turn it back on and then it will heat all the rads!

sullzz

When you bleed the rads upstairs do you have to repressurise the system

notahappycamper

No.

sullzz

notahappycamper wrote: »

No.

Well then you have a pressure reducing valve or an auto filling valve which is hiding a leak on your system which will ruin your 3year old boiler in no time , you should get this valve removed and see how long it takes for your system to drop to 0 bar , how often do you have to bleed your upstairs rads?

oikster

When you or your plumber were trying to vent your system,was it on or off,hot or cold because if the system was running and hot you wouldn't have a hope of venting it properly. You mentioned a radiator with a broken vent, how long has this been broken? Is your house timber framed and are the pipes run in the walls, if so surely you would see a leak.

sullzz

oikster wrote: »

When you or your plumber were trying to vent your system,was it on or off,hot or cold because if the system was running and hot you wouldn't have a hope of venting it properly. You mentioned a radiator with a broken vent, how long has this been broken? Is your house timber framed and are the pipes run in the walls, if so surely you would see a leak.

Boiler is located upstairs with 1 bar pressure , so its a sealed system , he has to bleed the upstairs rads a good bit and never has to repressurise the system , so there is an auto filling valve , a lot of air getting into the system means water is getting out , so there is a leak , could be the coil if all pipework is above ground

oikster

sullzz wrote: »

Boiler is located upstairs with 1 bar pressure , so its a sealed system , he has to bleed the upstairs rads a good bit and never has to repressurise the system , so there is an auto filling valve , a lot of air getting into the system means water is getting out, so there is a leak , could be the coil if all pipework is above ground

The only other thing I have ever come across was a leak at the boiler which only leaked very little and the heat of the boiler evaporated it. Made it very difficult to find.But I still think it hasn't been bled properly going by the suggestion that air was coming in through the heat exchanger.

sullzz

I have seen that too but if his boiler is upstairs its surely higher than his rads

notahappycamper

sullzz wrote: »

Well then you have a pressure reducing valve or an auto filling valve which is hiding a leak on your system which will ruin your 3year old boiler in no time , you should get this valve removed and see how long it takes for your system to drop to 0 bar , how often do you have to bleed your upstairs rads?

He's turned off the valve in the hot press, so I'll check to see how long it's takes to drop to zero. Also, the valve in the valve in the hot press for the hot water cylinder needs to be bled also.

Any reason why it's only the rads upstairs that need bleeding a lot? The rads downstairs are generally fine and need no or little bleeding. The boiler is located upstairs.

Thanks for replies and help so far!

sullzz

To me it sounds like a bad enough leak , rads upstairs and cylinder are highest point on the aystem , id double check that he turned the supply valve off mabey post a pic

oikster

Yes thought about that one too. But I have seen plenty systems in timber framed buildings albeit with the boilers downstairs giving terrible trouble with air and no sign of a leak. What about cavitation at the pump.

notahappycamper

Will post pics tomorrow. If its a flaming leak it'll be hard to find!

Billy Bunting

notahappycamper wrote: »

Any ideas folks?

Is it a presurised system ? sounds like a pump or balancing issue, i bit more info and pictures would help further.

notahappycamper

Billy Bunting wrote: »

Is it a presurised system ? sounds like a pump or balancing issue, i bit more info and pictures would help further.

I think its presurised. Water pressure is at 1.0 bar. Will post pics tomorrow.

notahappycamper

Pics as requested, cant post them in a single post.

notahappycamper

Pics:

notahappycamper

Pic:

notahappycamper

Pic:

notahappycamper

Pic:

notahappycamper

Pic:

notahappycamper

Pic:

notahappycamper

Pic:

oikster

Some pretty strange looking stuff happening here.Balancing valve for hot water coil can effectively kill supply to the system. Why is there a great big non-return valve on the fill. Looks like a starvation of water to me. But the way this is piped it is hard to know.Auto air vent would have been nice on the coil,a decent one that is. I wonder where the pump and motorised valves are.

I just checked out that boiler and it is a gas system boiler. At least I know where the pump is . Maybe one of the gas lads can shine some light here.

notahappycamper

oikster wrote: »

Some pretty strange looking stuff happening here.Balancing valve for hot water coil can effectively kill supply to the system. Why is there a great big non-return valve on the fill. Looks like a starvation of water to me. But the way this is piped it is hard to know.Auto air vent would have been nice on the coil,a decent one that is. I wonder where the pump and motorised valves are.

I just checked out that boiler and it is a gas system boiler. At least I know where the pump is . Maybe one of the gas lads can shine some light here.

The motorised valves are under the boiler.

oikster

What if the expansion vessel is bust and the pressure in the system is exceeding the safety valve. This would cause water to be ejected from the system and replaced by the filling loop,which should not be permanently connected ,back into the system.This could cause air to become trapped in the pipework.But unless your safety valve pipework is piped outside this will not be the case because you would see the water.

oikster

notahappycamper wrote: »

Pic:

What is happening here????:eek:

Sorry 5th pic down.