Hi,

 

My downstairs central heating pipes are 15mm copper but am I right in saying it should be in 22mm with 15mm at the radiators? I'm not sure what the upstairs is like.

 

What effect would it have being run in 15mm?

 

Cheers

 

Vijay

it depends on what KW radiators you have on the 15mm circuit no more than 5kw IMO

how do I work that out, from the size of rads (BTU output)?

measure height and width then look on screwfix to match up it will give you a rough idea or send me the sizes and i'll tell you a 600x1000mm single panel is about 1kw and a 600x1000mm is about 1.3kw

Downstairs there's 2 x 600x1300 wickes double convectors, a 600x1000 wickes double convector and a 300x1600 Screwfix single convector

600x 1300 are aporox 2.1kw each, 600x1000 are aprox 1.7kw, and 600x1600 are aprox 1.5kw thats nearly 7kw off 15mm pipe work plus pipe runs on top of that. do you think the radiators dont get the rooms hot enough? IMO it would have been piped in 22mm pipe

No, my house takes ages to heat up. There are some draughts which I need to sort but wondered about the pipeowrk. Would you say I'd notice a difference if it was in 22mm?

I personaly have never seen central heating pipes larger than 15mm in domestic properties.... smaller yes e.g. microbore and then 15mm at rads but this is only to eliminate the smaller pipe (microborwe) getting damaged by a hoover etc at rads.

 

No I don't think larger pipes would make a difference. It would be the size of rads etc. Btw...I am not a plumber. (I am a painter/decorator).This is just my opinion.

 

Hope thi is of help. ;)

typo ^ microbore

it would make a differance 15mm can carry 5kw max if you have 7 or 8 kw radiators on 15mm what do you think will happen? your radiators are rated to 70oc so check what heat your rads are kicking out if you have a condensing boiler it will be lower but you shouldn't be able to touch the rads at all when up to temp. if in doubt call a plumber out to check mate. as said above if your rads are under sized this could also be a factor but in that cause the rads will be very hot still

Not a plumber but swapped out all the rads and fitted new coper in my rental before i left the UK...As far as i know 15mm is standard for running to the rads. 22mm pipes are only really used to feed hot water to a tank and back to a boiler to increase flow. You might find 22mm where a condenser has been swapped in (where a tank was before?) which might have been 'fed' by a back boiler from a fire or range. putting in 22mm will get the heat around the system faster, but you'll lose heat through the extra bore!

 

Hope this helps!

here you go mate read this it comfirms what i have been saying, you will have 15mm going to the rads but the main flow and return should be 22mm if going over the KW 15mm will carry. oh and i am a plumber:p

http://www.deals4homes.co.uk/diyprojects/centralheating.htm

As above - 22mm main flow & return circs, with 15mm to each radiator. You might need to lift floor boards to check the main circ size.

What size are the pipes leaving the boiler? How many radiators have you got?

 

I have seen many systems piped up incorrectly and they work adequately....

If all of your rads get nice and hot, but your house is still cold then you need more rads and/or to look at draught proofing, insulation, windows etc...

I'll have a read in a minute Dipone but thank you ;)

 

Looked at the pipework a bit more today and downstairs is split into 2 circuits(in the kitchen), one that goes to the radiator in the hall and one that goes to the 3 radiators in my through lounge. Pretty sure it's 22mm coming from my boiler and think it goes to 15mm where it splits into 2 circuits.

 

My rad temps are as follows with the boiler near max:

 

Hall (600x1000) 46C after 1 hour and 49C after 2 hours

Back Room (600x1300) 44C after 1 hour and 47C after 2 hours

Front Room (600x1300) 42C after 1 hour and 53C after 2 hours

Front window (300x1600) 40C after 1 hour and 50C after 2 hours

 

The pipe insulation is pretty shoddy too.

Edited November 5, 200916 yr by vijay

here you go mate read this it comfirms what i have been saying, you will have 15mm going to the rads but the main flow and return should be 22mm if going over the KW 15mm will carry. oh and i am a plumber:p

http://www.deals4homes.co.uk/diyprojects/centralheating.htm

 

:p lol

:p lol

 

;)

 

you want 60-70 depending if you have a condensing system or not and they should be that temp well with in the hour if you have a combi system a bit longer if you have open vent system

;)

 

you want 60-70 depending if you have a condensing system or not and they should be that temp well with in the hour if you have a combi system a bit longer if you have open vent system

 

ok ok lol.;)

My boiler is a conventional boiler that was converted to a sealed system cos of the rad in my loft (conversion). Boiler is a Potterton 60E.

ok they have a cast iron heat exchanger so wont get as hot as quick but should still get to temp within the hour and to the temps i said

put your details in here and compare to what you have to rule out undersized rads

http://www.homesupply.co.uk/radiator_output_calculator.php

Edited November 6, 200916 yr by dipone

Just to add to this, we've just had an extension built but dad did the plumbing in it (as this extension was just an addition to the "old new" bit) and i know that all of the main circuit was 22mm dia, and 15mm to radiator. It is quite a big house though with alot of demand on the boiler. Still, certainly doesnt take an hour or more to get the radiators up to temperature!

a customer of mine asked me to install his boiler after he installed all the rest, as he saw plumbers in the past use nothing but pushfit and thought im not paying a plumber to do something i can do. anyway he piped the whole thing in 15mm apart from 3m that was in 22mm when i came to fit the boiler the first thing i said to him was you will never heat this house. he looked at me though i was a tw@t and laughed. come to comission the heating and all his rads would get too was 40oC and below the further down the line you go, then he felt the tw@t and had to rip most of it out to replace it with 22mm flow and returns this was on 7 rads. horses for courses

Im glad i gave up pluming. Fookin hate the job :rofl:

Just added all my details to that link and my rads should be more than capable of heating the rooms. Time to get my front bumper back on the car and get the floorboards up I think :)