Connecting new rads to system

[OldKettle]

Hi,
I am planning to install two new radiators into a room which is next to the boiler room, but which currently has no radiators.

I was originally planning to tee off from the main flow and return pipes from the boiler, but I would ideally prefer not to touch them. There is a radiator in the boiler room, which tees of the main pipes already, and I wonder if I could instead tee off from its loop (after raising radiator slightly, lengthening the pipes and adding tees).

These are the rads I'm planning to install (room is approx 10m x 5m).

https://www.wickes.co.uk/Wickes-Typ...ersal-Radiator---White-600-x-1200-mm/p/201486

Below are a couple of diagrams of the current/proposed design and a picture of the current boiler room.

Would the proposed design work? Any thoughts would be much appreciated.

I also ideally want to eventually create a separate zone for the room with the two new rads (and that zone can also include the boiler room rad). Does that impact how I should proceed for now?

 

[dilalio]

3 rads off 15mm might be pushing it. Resistance could be too much to encourage flow to the new rads and distance will add to this. Also depends on how you intend to control the new zone... Motorised valve or eTRVs former needs to go on 22mm pipe so you'd be better off extending the 22mm carcassing down from where it currently Tees to 15mm and then using that as a manifold for your new branches.

 

[OldKettle]

Thanks. To complicate the issue of flow further, I also need to take the pipework up to cross a passageway between the two rooms, as shown in the diagram below.

Could that work with 15mm, or is it definitely pushing it too much?

I could switch to a single (10,000BTU 3,000w) radiator positioned just inside the target room. Would that help?

 

[dilalio]

Would it not be possible to find the 22s upstairs and tee off them to drop down into the new room zone? Or tee off the 22s High up above the boiler.

 

[OldKettle]

Would it not be possible to find the 22s upstairs and tee off them to drop down into the new room zone? Or tee off the 22s High up above the boiler.

I'll have a look at this.

If I tee of the 22s somewhere, should I tee off with 22, and how far should I run the 22? All the way to the rads, and then just use 15 for the up pipes? (it's a concrete floor in the other room, so I will be running the pipes along the surface for now, possibly chasing them at a later date).

 

[dilalio]

2 drops to each rad would be best, so 2 pairs of Tees into the 22mm above (if it's there) and this can be done in 15mm. Also, don't forget to put drain cocks on each drop. Or get rad valves that have a drain cock on them.

 

[John D v2.0]

Would the proposed design work? Any thoughts would be much appreciated.

I'm no heating engineer but 4kw off a pair of 15mms would be no issue at all if it is only going to the next room, even if you go via the ceiling. The only reason the boiler outlet needs to be 22mm is because most boilers are rated 20kw+ for heating power and a 15mm pipe can't quite make it even with 20c temperature drop, and if the house is extensive ie not a flat the core would need to be 22mm because of the pump head.

 

[OldKettle]

Thanks for all of the above.

Having thought about it, I think that I might as well add the new rads as a separate zone (as it is a flat roofed extension).

I'm not keen about touching the 22mm pipes too near the boiler, just in case I muck it up and then have a job getting the boiler back on.

So, I think I will get a heating engineer to add a couple of zone valves at the boiler. Is it worth zoning upstairs and downstairs too (4 bed detached)?

I'll probably do the new rads and the 22mm up to the boiler room and then get the engineer to connect it to the new setup.

Does that seem to make sense? How much do you think I could be looking at for the new zoning work, and the hook up?