C
craigskelly
I would appreciate some help on pipe routing/size for heating to be installed within a new two storey extension I am building.
The existing heating system has 28mm pipe from the boiler but this changes to 22mm somewhere on the way to the pump. The pump feeds out in 22mm but I believe this is a short run in this size as from what I have been able to see so far, most pipe appears to be 15mm (will investigate further). The pump feeds all radiators from the 1st floor via a 1st floor loop and a series of drops. I have attached a drawing that shows both the original and new radiators. Point 7 on my drawing shows where the new radiators start (all new rads are to the right of 7) with points 1-7 being a ground floor loop and the other 1st floor radiators teeing off as shown. I have run new 15mm pipe to all new rads and originally intended to run these by connecting into the end of the original 1st floor pipe run (15mm) with the ground floor loop teeing off as a 15mm drop. I have actually already made the connection and can get heat to the furthest radiator but then commonsense prevailed and I realised that I am trying to run too many rads off of a 15mm feed. So, the situation is that radiators 5 and 6 are fed from 15mm pipe which is now under a wooden floor so can't be changed. However, I do have the opportunity to change the other pipe runs if necessary. I have now done some pipe sizing calcs and am thinking of running a new 22mm feed (although this is borderline so should I use 28mm pipe or is that not a good idea going from 22 to 28mm?) from the pump to point 7 i.e. leave the existing pipe run as is is without any additions. Also, rather than using a 15mm T to "drop" feed the ground floor rads from point 7, would I be better to T off in 22mm and then feed the loop from the other direction i.e. run in 22mm to rads 1-4 before the final runs to rads 5 and 6 which as I said are in 15mm.
There is a single thermostat on the ground floor and I intend installing a second unit in the new bedroom and possibly a third on the ground floor in the living room - is this recommended and do I need to install any valves in my design (there is already one for the hot water).
Finally, when sizing the pump, I am correct that I just need to work out the head required from the index circuit and not the total pipe run aren't I? The index circuit equates to the pipe run for the new rads and using 22mm pipe to point 7 equates to a head of about 0.9m although obviously if I change the design as described above I will need to re-do the calcs.
Thanks in advance for your help/guidance
The existing heating system has 28mm pipe from the boiler but this changes to 22mm somewhere on the way to the pump. The pump feeds out in 22mm but I believe this is a short run in this size as from what I have been able to see so far, most pipe appears to be 15mm (will investigate further). The pump feeds all radiators from the 1st floor via a 1st floor loop and a series of drops. I have attached a drawing that shows both the original and new radiators. Point 7 on my drawing shows where the new radiators start (all new rads are to the right of 7) with points 1-7 being a ground floor loop and the other 1st floor radiators teeing off as shown. I have run new 15mm pipe to all new rads and originally intended to run these by connecting into the end of the original 1st floor pipe run (15mm) with the ground floor loop teeing off as a 15mm drop. I have actually already made the connection and can get heat to the furthest radiator but then commonsense prevailed and I realised that I am trying to run too many rads off of a 15mm feed. So, the situation is that radiators 5 and 6 are fed from 15mm pipe which is now under a wooden floor so can't be changed. However, I do have the opportunity to change the other pipe runs if necessary. I have now done some pipe sizing calcs and am thinking of running a new 22mm feed (although this is borderline so should I use 28mm pipe or is that not a good idea going from 22 to 28mm?) from the pump to point 7 i.e. leave the existing pipe run as is is without any additions. Also, rather than using a 15mm T to "drop" feed the ground floor rads from point 7, would I be better to T off in 22mm and then feed the loop from the other direction i.e. run in 22mm to rads 1-4 before the final runs to rads 5 and 6 which as I said are in 15mm.
There is a single thermostat on the ground floor and I intend installing a second unit in the new bedroom and possibly a third on the ground floor in the living room - is this recommended and do I need to install any valves in my design (there is already one for the hot water).
Finally, when sizing the pump, I am correct that I just need to work out the head required from the index circuit and not the total pipe run aren't I? The index circuit equates to the pipe run for the new rads and using 22mm pipe to point 7 equates to a head of about 0.9m although obviously if I change the design as described above I will need to re-do the calcs.
Thanks in advance for your help/guidance
