Should I convert a one pipe system to a two pipe system?

[DJS1]

I've recently uncovered some of our CH pipework and realised that the majority of it is a one pipe system. Only two of the upstairs radiators have separate flow and return pipes (and the return is 15mm).

Putting a two pipe system in upstairs is quite a simple job, but is more difficult downstairs because of a mix of a exposed floorboards, parquet flooring and a concrete floor.

I'm toying with the idea of making it a two pipe system, but would you experts say it's worth it? A few of the downstairs radiators don't get very hot which is why I'm considering making the change, but I guess it may be worth balancing the system first.

My boiler is a 2 yr old WB condensing system boiler.

 

[glasgowgas]

does it say in yer MIs that you can have a one pipe system?

converting to a two pipe system would be a good idea

 

[doitall]

In the long term, because of the age of the pipework, yes, if it's convenient to upgrade the system now.

A one pipe is just as good as a two pipe, until people play with it and upset the balance and add bit's without having a clue, a two pipe system is more forgiving to DIYers and tradesmen that are lacking in knowledge.

 

[glasgowgas]

forgiving to DIYers and tradesmen that are lacking in knowledge

how is a one pipe system better than a two pipe system?

one pipe trvs cost 4 times a normal trv,plus big and ugly.

one pipe system,all presumed rads with one pipe trvs,all trvs closed due to room temp being up except,say last rad.
all that pipework being warmed up to heat one rad!!!!!

and are you suggesting i lack knowledge?

 

[doitall]

forgiving to DIYers and tradesmen that are lacking in knowledge

how is a one pipe system better than a two pipe system?

one pipe trvs cost 4 times a normal trv,plus big and ugly.

one pipe system,all presumed rads with one pipe trvs,all trvs closed due to room temp being up except,say last rad.
all that pipework being warmed up to heat one rad!!!!!

and are you suggesting i lack knowledge?

Did I say it was better, I said just as good.

A one pipe TRV is a lot cheaper than a complete repipe.

There's less pipe in a one pipe system than a two pipe, and both system can be controlled with room stat, and zoning )MVs).

Do you fully understand a onepipe system and how it can be beneficial in some installation, to have one pipe loops and even a mixture of both one and two pipes.

 

[glasgowgas]

Did I say it was better, I said just as good. NO IT ISN`T

A one pipe TRV is a lot cheaper than a complete repipe. DANFOSS ONE PIPE TRV = £32 X HOW MANY RADS 5,6 MAYBE 7?

There's less pipe in a one pipe system than a two pipe, and both system can be controlled with room stat, and zoning )MVs).THE SYSTEM IS 2 YEARS OLD IT SHOULD HAVE A ROOM STAT AND TRVS,LESS PIPE IN A ONE PIPE SYSTEM IN A DOMESTIC PROPERTY,THAN A TWO PIPE SYSTEM???? YOU ARE AFF YER NUT!!!!

Do you fully understand a onepipe system and how it can be beneficial in some installation, to have one pipe loops and even a mixture of both one and two pipes.INDUSTRIAL HEATING ENG WITH 25 YEARS EXPERIENCE,KNOW AS MUCH AS I WILL EVER NEED TO KNOW ABOUT ONE PIPE/TWO PIPE/MANIFOLD SYSTEMS/AHUs/BMS/OIL FIRED/GAS FIRED ET AL. OP HAS A SYSTEM BOILER,2 YEARS OLD,DOES THE MIs ALLOW A ONE PIPE SYSTEM

 

[doitall]

We shall disagree then.

25 years makes you a young pup.

 

[glasgowgas]

We shall disagree then.

25 years makes you a young pup.

yeah me and you can disagree but the OP is looking for advice.

maybe read between the lines a bit here,

the boiler is 2 years old,a few downstairs rads "don`t get very hot".

a small bet there is no trvs or zone valves fitted, roomstat would be a doubt as well.

if you were asked to fit a WB HE system boiler into the OPs pipework
would you?

and i aint no pup,more like a f#####g rottweiler

 

[doitall]

In the long term, because of the age of the pipework, yes, if it's convenient to upgrade the system now..

I gave the OP good advice in my opinion.

Yes I would fit a WB system boiler on a one pipe if it was in good condition, and met the regs.

Ok a rottweiler puppy

 

[glasgowgas]

in your opinion (and mine) your generic advice for a one pipe system
is correct (do not agree it is as good as a 2 pipe)

my first reply was to the OP in regards to the info he submitted.did you read his other post on this forum?

my alarm bell started ringing when he stated it was a 2 year old WB system boiler.

had a fag and a coffee, apologies to doitall for any aggresive postings

DJS1 any more relevant info, do you have trvs,or zone valves,roomstats,programmers,was it powerflushed etc etc

 

[bengasman]

Combined with the info from your other post, it would seem that your system is not in a great state, at least pipe-wise.

Personally, I would have a 2 pipe system any day of the week, but DIA is not an amateur, so I would not categorically state you can't have a one pipe system with a condensing boiler. I just would not know how to get an even distribution of heat, and realise a 20 degree differential as required on a steamer. (would you be so kind to point me in the right direction dia?)

Apart from that, I would be really curious to know how the installer cleaned a one pipe system properly.

One thing I would recommend, no matter where you go from here, stick a magnaclean on the return pipe close to the boiler, the sooner, the better.

 

[DJS1]

OK, I can see I've generated some healthy debate on here.

Rad's already had TRV's although I couldn't swear if they're the correct one's for a one pipe system, a room stat was installed at the same time as the boiler and there is an integral seven day programmer. An optional diverter valve went in the boiler, although I don't know much about this. Assuming that zone valves are external from the boiler, then we don't have any of these and I'm fairly sure it wasn't powerflushed.

Got to say the lack of cleaning is worrying me now. Is it worth me taking the rads off and hosing through them and would you all recommend the magnaclean?

 

[doitall]

Several point worth noting, If the pipes are all hidden as you say, it's quite likely the installer didn't know it was a one pipe system and indeed you are only assuming going on what is under the floor upstairs.

If it's is a one pipe system, you can be almost certain the wrong type are fitted, which would account for the poor circulation.

If it's a combi you don't need zone valves unless you have multiple zones.

Powerflushing a one pipe system is a waste of time, each rad needs to be flushed individually outside with a hose pipe.

A magnaclean is the best thing since they invented boilers, well modern bean cans anyway.

 

[Soggy_weetabix]

If possible ensure you plumb in a 'reverse return' if your re-piping the system.

Dave

 

[DJS1]

Thanks for your reply.

You're right, it's only an educated guess that it's a one pipe system downstairs, although I'm fairly confident of this as the flow pipe from upstairs to downstairs is exposed and there's no corresponding return pipe.

Our boiler is a system boiler, not a combi, does this mean we should have zone valves? We do have this internal diverter valve but I don't know what that does.

I think we'll be investing in a Magnaclean shortly and it looks like my bank holiday is now sorted - flushing rads in the garden!

Thanks again for your time.