One pipe central heating system

[dilalio]

Would stem reply to this please



Thanks
JamesEB.

Not Stem but believe I can reply in his stead ...

Undoubtedly, parts, if not all of the floors will need to come up. The extent of which depends on current pipe routes and if you’d prefer to have replacement pipes concealed rather than surface runs.

Pricing is not really done here as a matter of principle, let alone the number of variables that come into play... but your are looking at 1000’s not 100’s...

Location; size of property; construction; building fabric; furnishings; decor; occupancy and access are all factors that will influence any “estimate” given and this is impossible to assess remotely.

Get 3 prices from local independents, who can visit and evaluate.

Edit: FFS! You 2 posted while I was replying

 

[stem]

Is your system not working very well ?

Old&Cold asks a good question. I know of properly designed and installed one pipe systems that work OK, if yours is one of those then maybe something else is amiss.

 

[ASKI]

I recently made a start at converting my old 1-pipe system. See:

https://www.diynot.com/diy/threads/...ng-improve-and-add-a-rad.497803/#post-4092401

So far, I've converted 2 radiators and the difference is immense. They heat up 10x quicker than before, and get a good 20 deg higher than they used to.

I'll be converting the rest over the summer months!

I gather 1-pipe systems may work ok in some cases, but for mine, the difference is sufficient to justify the disruption of conversion.

 

[garyo]

I have a one-pipe system and it works surprisingly well, if a little inconsistent from one rad to the next. My house actually has 2 x one-pipe systems - one for upstairs and one downstairs.

Both of my one-pipes are 22mm, with the rads directly above the pipe linked by 15mm. A couple of the rads have been fitted to the one-pipe and then have their own return, and plumbed directly in series, so consequently get very very hot unless I balance them carefully.

It made me think though - is there an equivalent of a 3-way divertor valve you can fit to the rad feed from a one pipe so that you could 'balance' each rad between
a) All flow to go directly though rad (which you might use towards the end of the run, or even just plumb the rad in series towards the end) and
b) all flow to run under the rad and let gravity do its work?

I suppose that could be achieved using a 22mm check value but having one of those under the floor next to each rad doesn't seem like it'd be very reliable/serviceable.

 

[CWHEATING]

One pipe systems work on convection so the water in the pipework that runs under the radiators gets heated up and as we all know heat rises causing the radiators to eventually get hot. This is why adding a two pipe system on to a one pipe drastically affects the circulation causing you not have a good flow and return as needed. Adding new condensing boilers onto one pipe system is not recommended unless a low loss header is fitted.

 

[JamesEB]

Sorry for the long response to this. I've been ill.

To improve the circulation by adjusting the one pipe to a two pipe system they said I needed a new boiler to support it as mine is very old.

Is this correct please?

Thanks
JamesEB

 

[ericmark]

A one pipe system could in some ways work better than a two pipe system with a modern boiler, the aim is to send out hot water then receive back water cool enough to cause moisture in flue gases to turn to water, one way to do this is to restrict the flow through the radiators, however with fan assisted radiators flow is not restricted the fan speed controls output, never tried it but one pipe could work better?

If it works then leave it, if it does not work explain the problem, not always a case of good or bad, but just different.

The one pipe systems I worked on did not have a return, steam from boiler was fed to radiator and water dribbled into a drain, very efficient, but it ensured flow of steam used for other uses.

 

[muggles]

Sorry for the long response to this. I've been ill.

To improve the circulation by adjusting the one pipe to a two pipe system they said I needed a new boiler to support it as mine is very old.

Is this correct please?

Thanks
JamesEB

No, not at all. Any boiler which can accommodate a one-pipe system can also accommodate a two-pipe system. They're just trying to take advantage and sell you a new boiler. Find a different installer

 

[75pete]

In 1973ish, in my first house, 3 bed 1913 build, I installed a 7 rad single piped heating system, gas boiler and hot water cylinder.
A couple of very important points for this type of system, as I recall, are to ensure the pipes are properly deburred and to use swept elbows, and the correct distance between the connections of each rad. The last point in to spend time balancing the system.
It was a great success.

 

[JamesEB]

Thanks again everyone.

Balancing the system is something I don't know how to do.

Are there any instructions please?

JamesEB

 

[fine tune]

top of page ,comes under faqs

 

[stem]

They are in the wiki / plumbing / FAQ's here. But it's a bit different with a one pipe system, in that the readings won't work quite the same. This is because the pump circulates the water around the one pipe loop rather than directly forcing it through the radiators. The flow through the loop won't change by adjusting the lockshields. But, the principle still applies, in that the lockshields can be adjusted gradually in the order that the radiators heat up, so that those further whilst they get the same flow, will have more heat as it not been removed by those earlier in the supply. As larger radiators will require more heat than smaller ones, you may need to make an adjustment to take that into consideration too. Trial and error really.

 

[JamesEB]

In 1973ish, in my first house, 3 bed 1913 build, I installed a 7 rad single piped heating system, gas boiler and hot water cylinder. The last point is to spend time balancing the system.
It was a great success.

Thanks everybody.

I was hoping 75pete would reply as he seems expert in what I need. We have had this system for many years and what I need to know is what to do to "spend time balancing the system".

Thanks for help
JamesEB

 

[Deleted member 221031]

You can tee between flow and return. If the radiator is high from the floor it can be done above the floor.

It doesn’t look brilliant. But it makes it work

 

[JamesEB]

You can tee between flow and return. If the radiator is high from the floor it can be done above the floor.

It doesn’t look brilliant. But it makes it work

Sorry but I don't understand this at all.

JamesEB