The Builder. Posted April 26, 2006 Share Posted April 26, 2006 New boiler installation, a large one with 28mm outlets.In general how much of the distribution should be in 28mm for an average 3-bed 2 storey house? Should I reduce to 22mm to cross rooms and then 15mm to rad tails or do as much as poss in 28mm? Link to comment Share on other sites More sharing options...
Gluestick Posted April 26, 2006 Share Posted April 26, 2006 All depends on the flows.28 m.m. sounds like overkill. I have to feed circa 40 feet along and then 15 feet across and then 88 feet all the way down and 15 across the house, again and then 30 feet along. This should be OK in 22 m.m., but to be sure, I am putting a second criculating pump at the extreme end of the return circuit.Then, later, I will go up into the converted loft and a similar round trip journey! Another pump up there too, I think! Link to comment Share on other sites More sharing options...
Michael Posted April 26, 2006 Share Posted April 26, 2006 Build docter. 22mm off the boiler is ok for the average 3 bed etc,its good practise to take 22mm to last but one rad then splitting 22+15+15 to each.I take it your in the uk useing this pipework,before i get jumped on by the french.. experts.22mm pipes gives 45,000Btus.15mm gives15,000 rule of thumb, If you want to caculate this into your rad sizes.ie-one rad say 5000 btus second rad 10.000 btus, combined total 15.000 btus This is where and why it splits 22+15+15.Plane as mud i hope. Michael. Link to comment Share on other sites More sharing options...
Michael Posted April 26, 2006 Share Posted April 26, 2006 Or even plain as day.Michael before dick picks me up,Michael Link to comment Share on other sites More sharing options...
powerdesal Posted April 27, 2006 Share Posted April 27, 2006 BD,I suggest the following site will answer all your questions:-www.diydata.com/planning/ch_design/limiting_factors.htm(hash)capacitySorry but my hash key does not work for some reason.The whole site is, IMHO, brilliant for CH design calcs.Regards Link to comment Share on other sites More sharing options...
Michael Posted April 27, 2006 Share Posted April 27, 2006 Gluestick . Your system sounds like overkill,one pump is ok,something like a granfoss variable head pump will do the whole job.Depending on how many rads etc and Btus of the boiler is the factor what size pipe pipes is installed.,if you use more than one pump for a booster its designed wrong.or if its a very large semi commercial system and you are useing a second pump for the primarys to the hws.Michael. Link to comment Share on other sites More sharing options...
Gluestick Posted April 27, 2006 Share Posted April 27, 2006 Michael:Many thanks for that. I am following, in theory, the advice of my chum and client, who is a semi-retired heating engineer.What we have agreed, in principle, is to make provision for the second pump, in case it's needed.In fact, for the upstairs, I will zone the whole circuit with a motorised valve and a demand pump.With some luck, the downstairs circuit should be OK:[8-)]. However, circa 182 feet out and 182 feet back is quite a long flow circuit! Far better if the pipes were flow-graded 28 m.m. down to 22 m.m. and finally 16 m.m etc, but the 28 m.m. would look unsightly since it will all be surface mounted. (Solid floor).C'est La vie ! Link to comment Share on other sites More sharing options...
Steph1 Posted April 27, 2006 Share Posted April 27, 2006 HiCan you get 22mm PER plastic pipe in France? Link to comment Share on other sites More sharing options...
Gluestick Posted April 27, 2006 Share Posted April 27, 2006 Certainly can.Quite a bit on that topic here. http://www.completefrance.com/cs/forums/649721/ShowPost.aspx Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.