Central heating?

[Susiwaa]

How do I work out what kind of pipe system my central heating has?

The radiator in our front room stops working when the temperature gets below about -5.

The room is North facing.

We know the pipe is freezing somewhere under the floor but as the pipework was done before we moved in I don't know if the radiator pipe system is a "one pipe" or a "two pipe". Or something completely different! ;-)

We will need to lift the floor and insulate the pipes, in the summer, but looking for easy solutions to tide us through this very cold "snap"

[Odsox]

Not being a plumber I could well be wrong, and I'm sure someone will take great delight in telling me so ... but I don't think you can have a "one pipe" system. You need a flow and a return pipe, otherwise if you only have one pipe and you switch one radiator off the flow is stopped and ALL the radiators would go off.
Best thing to do is find the header tank in the loft, drain the system and refill it with anti-freeze designed for central heating systems.

Lagging the pipes is of course still necessary as you are losing heat, but not so essential right now.

[The Riff-Raff Element]

Not being a plumber I could well be wrong, and I'm sure someone will take great delight in telling me so ... but I don't think you can have a "one pipe" system.

I take no delight whatsoever in saying that "one pipe" systems do exist. At least, they do in France, though they are an anachronism.

Basically, a single pipe runs in a circuit from and back to the boiler. Radiators are normally spurred off, though in some cases (the first and last radiators on the system we inherited) the radiator is the pipe, so shutting either of these in closes the system.

I believe that the practice was abandoned because the pressure used in the system needs to be pretty high for it to work properly - about 3 barg: this means that the pipework needs to be heavier gauge copper and the pipe joints must be brazed rather than soldered (actually in France, this is true for all plumbing ) which really bumps up the cost.

How could you tell? Well, the obvious way is to see whether the pipe leaving the radiator joins the same pipe as the incoming pipe, though if it's beneath the boards that isn't going to work. Is there anyway you could just take a peek?

[Susiwaa]

Thanks!

Don't have a header tank, Odsox, or a water tank for that matter! Got a new condensing boiler installed 3 years back. Existing pipes/radiators were deemed sufficient enough for the system.

Not sure Riff-Raff, would have to lift the carpet which means moving loads of furniture (not to mention clutter) If I could work out where the pipes were then at least I could lift the right boards!

Think it's going to have to wait till a warmer day (Friday is supposed to be 1 degree! lol ! ) but will need done before long. And yes, insulation shall happen!

On the plus side, my dream of a lovely wooden floor in the front room may happen if we have to do all this work anyway! ;-)

[Millymollymandy]

Not being a plumber I could well be wrong, and I'm sure someone will take great delight in telling me so ... but I don't think you can have a "one pipe" system.

I take no delight whatsoever in saying that "one pipe" systems do exist. At least, they do in France, though they are an anachronism.

Basically, a single pipe runs in a circuit from and back to the boiler. Radiators are normally spurred off, though in some cases (the first and last radiators on the system we inherited) the radiator is the pipe, so shutting either of these in closes the system.

I believe that the practice was abandoned because the pressure used in the system needs to be pretty high for it to work properly - about 3 barg: this means that the pipework needs to be heavier gauge copper and the pipe joints must be brazed rather than soldered (actually in France, this is true for all plumbing ) which really bumps up the cost.

How could you tell? Well, the obvious way is to see whether the pipe leaving the radiator joins the same pipe as the incoming pipe, though if it's beneath the boards that isn't going to work. Is there anyway you could just take a peek?

Had that system in my last house and we couldn't turn off any rads, it was all or nothing.

Hope you can get it sorted Susiwaa as it must be very frustrating, just when you need the heat!

[grahamhobbs]

I find it difficult to believe that the pipes to one radiator would freeze if all the others are working. Are you sure that it is not a coincidental problem, such as an air lock in that radiator or a dodgy valve.

If it is really only one radiator that stops working due to the pipes freezing, it would tend to imply that there is a long branch off the main circuit (single or double doesn't matter) to that particular radiator otherwise the hot water circulating would soon melt the frozen pipe. That branch must also be exposed to freezing air, perhaps it runs past an airbrick venting the underfloor area. As a temporary measure, during the severe weather, these vents could be closed off.

If the pipes are frozen they may have burst the pipes and soon as they thaw then water is going to bleed out of the circuit.

Anti-freeze not only will prevent freezing but also prevents corrosion in your system.

[Susiwaa]

I find it difficult to believe that the pipes to one radiator would freeze if all the others are working. Are you sure that it is not a coincidental problem, such as an air lock in that radiator or a dodgy valve.

If it is really only one radiator that stops working due to the pipes freezing, it would tend to imply that there is a long branch off the main circuit (single or double doesn't matter) to that particular radiator otherwise the hot water circulating would soon melt the frozen pipe. That branch must also be exposed to freezing air, perhaps it runs past an airbrick venting the underfloor area. As a temporary measure, during the severe weather, these vents could be closed off.

If the pipes are frozen they may have burst the pipes and soon as they thaw then water is going to bleed out of the circuit.

Anti-freeze not only will prevent freezing but also prevents corrosion in your system.

Thanks! Good advice there :)

We got it fixed only last week. it stopped working but then came back by later in the day when the temperature rose and we'd dug all the snow away from round the house. Then 3 days later, when it was about -12 out there, it happened again, this time not coming back to life. But the temperature didn't rise above about -6. The engineer came out and did lots of stuff, he initially thought it was sludge, but on draining the radiator found it to be clear. After faffing about with it, he got it working and agreed that it must have been frozen.

I like the air vent theory, we just so happen to have a rather annoying one right under the offending radiator. One that a heating engineer kindly made bigger a few years ago! Not convinced we need it at all now we have no gas appliances in the room.

Other than lifting the floor, how would I know if the pipe has burst? Would the system stop working completely?

And how do we add antifreeze to the system with no header tank? Would this have to be done by an engineer? (I'm scared stiff of the boiler cos it's gas! Give me a wood stove any day)

Oops, loads of questions!

[grahamhobbs]

If you don't have a 'header' tank then you must have a fairly modern system with an expansion vessel (a round bright red tank). There is no easy way to add an anti-freeze/inhibitor into the system. Basically you need to drain down the system a bit and add the antifreeze anywhere convenient, perhaps a towel rail has a convenient nut you can undo, otherwise I believe you can buy some that will fit on the the 'filling loop' connection. Sorry I'm a builder not a plumber.

[Susiwaa]

Thanks (again)

Pipe has now burst before we could do anything to try and make it better.

Engineer/plumber called, hoping for first call tomorrow. Crossing everything.

Off to wrap up warm and dream of wood burners!

[MKG]

Sorry to hear that, Susiwaa - but at least now you know what the problem was. If the pipe burst, it was definitely frozen. But that sounds so improbable to me that I'd get someone to check it out thoroughly - a hot-water system freezing may well indicate a blockage of another sort.

Just a thought.

Mike

[Susiwaa]

Thanks Mike!

Think the blockage is ice! Have located burst pipe ourselves, despite the engineer telling us that it wasn't burst etc etc.

It is and exactly where I thought it may be (only because it's where the noise came from)

Now have no heating till at least Sunday, emergency plumber called (via house insurance) to fix it.

Shall be investigating getting underfloor heating which does not involve water or gas boiler power as this has been way too stressful for my liking.

Thanks to everyone for their helpful tips, I have learned alot about pipes and heating. Also now know that I do indeed have a two pipe system and stupidly long lengths of pipe under my livingroom floor.

Happy Christmas, however you celebrate it!