Water discharging from the loft vent pipe as CH turns off?

[Markw996]

Hi,
I have just moved into my first home, a 2 bed semi-detatched and as the title says I have a very noisy central heating system.

As it comes on I get lots of bubbling / gurgling noises that last about 10 seconds and seem to originate from either the upstairs radiators or the airing cupboard.

Also as the central heating clicks off it sounds like someone emptying a bucket of water up in the loft right above my bedroom (very worrying the first time it happened!).
I traced the loft noise to the expansion tank in the loft where, as the heating clicks off, I am getting about half a litre of water discharging from the vent pipe back into the tank.

The system is open vented circa 1992 and I take the vent pipe to be the one that rises about a foot above the tank, then bends in a U shape back down into the tank.

I've had breif discussions with a plumber friend and he says it could be the boiler thermostat?!? but I suspect it is more likely to be air in the system somewhere (although I am certainly not clued up on central heating systems) as I did have to bleed a lot of air from by bathroom radiator when I first moved into the house due to it being very cold at the top.

Just to summarise:
I have 2 tanks in my loft and the problem is relating to the smaller tank which does the central heating.
My boiler is located in a downstairs cupboard.
My airing cupboard is upstairs and contains an immersion tank, pump, and a motorised valve of some sort.

I hope someone can help as the noises wake me up in the mornings and annoy the hell out of me in the evenings! (

Many Thanks,
Mark.

 

[marinegmillie]

Cold feed and vent go up a foot with ya arrows, spot on.

 

[jase158]

This is what everything is?
To everyone who say i am wronge, this is the way i got taught Last year.
So obviously you have all done it and maybe there are hundreds of them out there but that doesnt mean it is right?

 

[marinegmillie]

Spot on jase158!

 

[yorkieplumber]

Agree spot on!

 

[yorkieplumber]

but in a earlier post jase, you said it was wrong, am confused now.

 

[Reg Man]

Jase158, I take it that we can now disregard your post number 18, and we will go with your post number 22.

 

[marinegmillie]

I think what he ment is where the cold feed and vent is piped to pump, the cold feed is quite direct into pump, maybe pulling in some water hence venting back over to get rid, just a thought.

 

[jase158]

but in a earlier post jase, you said it was wrong, am confused now.

I was saying the arrowed pipe is wrong as it is pumping water through the return? the opposite way that you want it? I have never seen one of these installed like this?
And secondly I have never seen a fully pumped system this way? I have learnt something and it proves that college is absolutely useless, all my diagrams in my books show the vent and cold feed going into the boiler, but the pump should be after the vent and cold feed. Surely there must be another way as this looks to me like it will draw water from the F and E tank.

 

[jase158]

I think what he ment is where the cold feed and vent is piped to pump, the cold feed is quite direct into pump, maybe pulling in some water hence venting back over to get rid, just a thought.

finally somebody who understands, is there no other way that this can be piped up?
And for all those who say that this is ancient plumbing, my plumbing doesnt even have a pump. So pumped central heating only cant be that ancient.

 

[Reg Man]

Jase158, I thinking about sliting my wrist over this thread. There are alot of forum members who have an enormous amount of experience probably some go back to 1960's. The H lay out as it is known has been around since the introduction of fully pumped central heating systems back in the 1970's. It is the only proven method of installation which works and does not cause pumping over on an open system Ect: Give me any manufacturer boiler instructions from this time to current day and it will show this method of piping. Your labeling on the photograph is spot on.

 

[jase158]

Jase158, I thinking about sliting my wrist over this thread.

Thats a bit drastic? I was saying that i was wronge and everyone else is right,

May i just explain a couple things,
1. I have never installed a pump or a full central heating system
2. I am relatively new to plumbing, compared to some of the people on here,
But what i am saying is, just because everybody does it this way and it works this way doesn't neccessarily mean its right, although it is right this time
and isn't there any other way of doing it?

 

[jase158]

Let me just ask a question.
Where the pump connects in does it pull water as well as push the water around the system? or does it simply push the water round?
If it pushes only then obviously this is where i am getting confused, but if it pulls the water, what prevents it from pulling the water from the F and E?

 

[Reg Man]

Thanks jase158, feel better now.

The best leap forward I think, is sealed systems. They don't suffer many of the water quality problems you get on the open systems. Only draw back is the manual top up.

 

[jase158]

Thanks jase158, feel better now.

The best leap forward I think, is sealed systems. They don't suffer many of the water quality problems you get on the open systems. Only draw back is the manual top up.

Doesnt this have to be a new (ish) boiler though, Condensing type or combi? as there has to be a AAV, Expansion Vessel and PRV?

 

[Reg Man]

From post 19 Quote:The concept is worked by locating the open vent a cold feed as close together as possible (within 150mm) on the flow pipe before the pump. The reason it has to be before the pump, is that this area will be the place of the least pressure on the system therefore preventing circulation into the header cistern. Quote:

 

[Reg Man]

Doesnt this have to be a new (ish) boiler though, Condensing type or combi? as there has to be a AAV, Expansion Vessel and PRV?

Not necessarily. I fitted sealed systems back in the 1980's on cast iron boilers. They did have to be fitted with overheat thermostats and manufacturer would have to state it was suitable for sealed systems. The expansion vessel, PRV, Pressure gauge and filling loop were the extra bits we had to install.

 

[RoryD]

You have a blockage, you will need a powerflush and perhaps a reconfiguration (clearly haven't seen the system). I get this all the time mate.

 

[Markw996]

You have a blockage, you will need a powerflush and perhaps a reconfiguration (clearly haven't seen the system). I get this all the time mate.

Thanks, I have a plumber coming to powerflush the system tomorrow afternoon, in preparation of me fitting all new TRVs and a Magnaclean.

I might ask him to fit an air separator at a later date as I can't get my head around the flow & return connections.

 

[tamz]

Jase158, I thinking about sliting my wrist over this thread

May i just explain a couple things,
1. I have never installed a pump or a full central heating system
2. I am relatively new to plumbing, compared to some of the people on here,
But what i am saying is, just because everybody does it this way and it works this way doesn't neccessarily mean its right, although it is right this time
and isn't there any other way of doing it?

Still got a lot of learning to do eh

Let me just ask a question.
Where the pump connects in does it pull water as well as push the water around the system? or does it simply push the water round?
If it pushes only then obviously this is where i am getting confused, but if it pulls the water, what prevents it from pulling the water from the F and E?

If i have time later i will draw you a couple of pictures that will help explain how it works.

 

[philip mc geown]

i agree have been in many an old house with this type of layout, but it is a reconised piping method and many people still use it 2day!

 

[fuzzy]

cannot see how that system works, isnt the return joing on the positive side of the flow, how does the water get round?

 

[fuzzy]

oh its a bi pass i presume, will adding a bi pass valve help?

 

[tamz]

oh its a bi pass i presume, will adding a bi pass valve help?

It is a bypass without a valve. Fitted by an eejit as it is not necessary in the first place and if he fits one, at least valve it.

If the kids don't come through i'll not be doing much tomorrow so i may explain how different systems work with a few drawings.

Clue = neutral point.

 

[efficient]

got to be the best post ive read.... ****ing myself here about you lot arguing over a basic layout. The layout is spot on other than the bypass needs a ABV on it. If there is water coming out the vent pipe then theres got to be a blockage not allowing the circulation hence water coming out the vent its got nowhere else to go..

 

[Reg Man]

got to be the best post ive read.... ****ing myself here about you lot arguing over a basic layout. The layout is spot on other than the bypass needs a ABV on it. If there is water coming out the vent pipe then theres got to be a blockage not allowing the circulation hence water coming out the vent its got nowhere else to go..

Totaly agree. Its basic layout, the only way to pipe up open systems over the years. I think some of the forum posts, got a little consfused.