This weekends fun will be placing the pipes for the two rads in the extension, will it be OK just to clip the microbore (10mm) to the surface of the blocks and then just plaster over them or will they require conduit?
cheers
Plaster does not attack copper so it is not necessary.
Although I would be tempted to use plastic for anything buried in a wall.
Christian.
What about expansion and contraction as the pipes heat up? Doesn't this crack plaster?
R.
It is better to sleeve it to allow for expansion; corrosion isn't an issue.
On a side note, have you verified that 10mm tube will carry the necessary flow rate of water for the distance required and heat output of the radiators?
Although I guess you probably should take some precautions (not sure what) - this is what I did some 5 years ago - so far no problems and no cracking etc
Jon
Hi its 10mm that serve the rest of the house and there are longer runs than the ones I will be putting in, so should be fine :-)
Hi, forgot to mention that there will be 10mm sand cement coat first then pink
OK... Have you sized the radiators for the heatloss of the room and from that the flow required?
It may well all be OK, but it would be very prudent to do the sums properly and check.
10mm would be OK for a larger number of smaller radiators, but if you are hoping to have a single 3-4kW radiator, then it is important to check.You would be very tearful in a few weeks time if you discovered that the radiators are not heating the space adequately because they are undersized and that upgrading to the correct size meant pipes of > 10mm
Apologies if I 'm teaching granny to suck eggs, but it wouldn't be the first time that radiators had been guesstimated and found wanting.
I'd do the usual and wrap the pipe in closure tape before burying it.
Cheers, what I'm going off isn't science :-). The furthest fed rad in the house is the lounge, its a 5ft double and fed off 10mm, with the trv open and the boiler on "tickover" you cant put your hand on it!. The upstairs rad will be no issue as it will be an extension (extra 2m) of an exisiting rad thats been removed from the hall where I knocked through. The downstairs will be a little bit more hit and miss as it will be tee'd off an existing rad and will be 6m "downstream". With me tee'ing off I'm stuck with using the 10mm feed off the exisiting rad ( small 2ft double) both new rads are 4ft doubles. At the moment I have the trv's set at 2 and the boiler is on its first quater ( if that makes sense?) and it's fine so I've a long way left to "pump it up".
If I'm way off the mark I'd be glad for any advice.
Ta
OK, so a larger one than was previously in the hall?
Do you know that they will provide adequate heat for the space?
Unfortunately that's not really the issue. Having a 5ft radiator on a long run and having adequate heat for the room from it, probably means that you are OK in terms of being able to feed a 5ft radiator anywhere in the house. However, a radiator can be very hot on the top, and because of low flow rate, almost cold on the return pipe. This means it won't be prviding full output and therefore may not be enough to warm the room if you have used manufacturer data to choose radiator size.
The question is whether that radiator size or the 4ft one you propose will adequately heat the space. If it doesn't and you needed to go for a 6ft one for example, in order to get enough heat for the space, then 10mm may not be enough.
Let me give you a simple example. In my conservatory, I have a 5kW radiator - a large double panel job with fins. All of the other radiators in the house are connected via 8mm microbore. However, because of good insulation, none of those are larger than 1500W output. You can calculate the volume of water required to achieve the output. It is proportional to the temperature drop across the radiator (12 degrees for a conventional boiler and 20 for a condensing boiler) and the rate of flow. The important point is that the flow rate must be enough to maintain the correct temperature drop or the heat output will be less than that rated. Copper tube can support a maximum flow rate of 1.5m/sec without becoming noisy. Resistance gets worse with longer lengths as well. You can calculate the pipe size required to transport the volume of water needed to provide the heat for the radiator.
To cut a long story short, because I was short of time, a heating engineer was hired to connect the radiator. He insisted on using 8mm tube because that had been used elsewhere and refused to listen to my arguments that it would be inadequate. When put into operation, the radiator became hot at the top but the return temperature, was only 50 degrees when it should have been 70. Heating was inadequate. He was therefore asked to do the job again in the correctly sized 15mm tube. This cost him half a day and £30 in Fernox.
So I would say, do at least check the heat loss. At a minimum, look at radiator sizings in other rooms and then scale them according to floor area for the extension areas. If these make sense and you feel you have sized radiators adequately and they are less than existing, then you should be OK.
If undersized, you would have to add more radiators, with pipes home run back to the manifolds or go for larger radiators and possibly larger pipes. Realise that if the flow is inadequate, opening the TRVs won't help. You could improve flow a little by reducing that through other radiators, but with 10mm pipe the effect of doing that is not as marked as with 15mm and there is a limit to what can be done.
Thanks, the rad sizes are around the same for similar rooms in the house, apart from the lounge which the heating engineer fitted a 6ft double ( I said 5 ft in the last post but its 6ft) so in effect a 12ft rad !! I usually have this on one on the trv as it gets too warm ! Lounge is 5m X 4m, two of the bedrooms are the same size and are heated very adequately on twin 4 footers, I never really like the house too warm and we never really get "the freeze" as bad as the rest of the country as we seem to have our own microclimate on Anglesey and it helps in the winter being on a small island warmed by the sea !!
However, I once went walking in February near Amlwch and it sleeted horizontally. ;-)
Should have known better, I suppose. That was in the days when a bus ride to Llandudno Junction was necessary to find an open pub on a Sunday.
!!! that's a totally different situation, as sand-cement isn't plaster, and cement *does* attack copper. So yes, you should definitely wrap them in 'denso' tape or enclose them in conduit.
David
Snow never seems to stay for long, probably the salt in the air. Not quite 24 hr drinking here now but not far off !!
I see. Beaumaris?
or if you want to take your life in your hands, have a drink in Holyhead ;-)
It seems to have all the trappings of a sea port. :-)
Is that where you are?
no, I'm "east coast"
HomeOwnersHub website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.