Is the "flow" of the CH pipe run critical to good efficiency and reliability of the system?

[Brigadier]

Just bought a dormer bungalow, with a solid concrete floor downstairs and floorboards upstairs.

Due to layout of doorways etc, I can't see being able to have the pipes routed in a single loop; there will have to be two loops.

Currently, done in surface-mounted microbore.

Don't want to channel into the floor, and am happy to run all of the pipes in nicely-finished skirting boxings with one or two vertical boxings.

Would a "loop" feeding hall / bathroom / kitchen, with a separate "loop" feeding lounge / bed 2 / bed 3 / landing be good practice?

Will try and do a diagram to better illustrate issue in due course.

 

[Madrab]

The other alternative would be to run the pipework into the roof space with drops to every rad.

Your idea isn't 'bad practice' as such, it's just the more the design moves away from a central backbone with a single loop with similar feed lengths to each rad, the harder the balancing becomes as the lengths become more uneven.

 

[Brigadier]

Boiler on first floor.
Brick-built chimney ground to first, exiting through roof at ridge. Redundant.

Think I've sorted it:

Two-pipe flow and return system in 15mm, except first runs in 22mm as below.

22mm flow + returns from boiler to chimney breast (under floorboards).
Branch 1:
22mm flow + return to landing rad. Reduce to 15 mm f+r before rad.
15mm f+r feeds down corner of lounge, to catch lounge rad.
Lounge rad. to bed 2 (ground floor) rad., in 15mm.
Bed 2 rad. to bed 3 (ground floor) rad. in 15mm.
Branch 1 ends here.


Branch 2:
22mm flow + return (down to ground) on side of chimney breast. Reduce to 15 mm f+r before rad.
15mm f+r feeds to catch hall rad.
Hall rad. to bathroom rad (ground floor) rad., in 15mm.
Bathroom rad. to kitchen (ground floor) rad. in 15mm.
Branch 2 ends here.


Then, it is just a case of correct balancing being done, so both branches are at full efficiency, I expect?

Finally, a Magnaclean or some such, somewhere, to prolong the efficiency and longevity of the system?

Something for the spring though, just trying to get ducks lined up.

Have tried to get a couple of plumbers to have a look (towards this in 2023 but, perhaps unsurprisingly, no-one has even returned the calls).


Thanks in anticipation.

 

[Brigadier]

The other alternative would be to run the pipework into the roof space with drops to every rad.

Your idea isn't 'bad practice' as such, it's just the more the design moves away from a central backbone with a single loop with similar feed lengths to each rad, the harder the balancing becomes as the lengths become more uneven.

Sorry Madrab, rereading this and I'm struggling with your thought process.

How would running the loop at skirting level (with c. 12" feeds up to each rad.) be "uneven feed lengths" compared to dropping each down c. 7' from the ceiling?

The rads are in the same location in each case; the only difference being in your model the feeds to the valves are 7', and in mine, 1'.

Or have I completely misunderstood something?

 

[Madrab]

If the case would be that if a single 22mm backbone could be run above the ceiling then drops in 15mm to each rad as against running 2 loops at ground level, some dropping from 22mm to extended 15mm to feed more than 1 rad. Then the former would be preferable.

The minute you drop the backbone down to 15mm to feed more than 1 radiator you will almost certainly have a careful balancing exercise to perform, if they are large rads then feeding more than 1 in 15mm isn't the best idea as they may struggle to heat up properly.

May not be too bad given it's only 7 rads but that would really be dictated by overall distances and sizes of rads.

 

[Brigadier]

Presumably for cost then (and a bit of room too!) , but why wouldn't people just run 22mm f+R (in skirting boxing) and feed each rad in 15mm instead?

My original question (and prospective answer) was based on my seeing this diagram during my initial research:

Which appears to show 22mm F+R reducing to 15mm before each branch starts.

Unless told "absolutely baaaad idea!" - with explanation as to why - it is looking like original plan (chimney breast drops) with perimeter boxing and each rad teed from that, 22mm for everything except each rads' tees.

 

[winston1]

What is actually wrong with the existing system?

 

[Brigadier]

What is actually wrong with the existing system?

Old rads. Microbore everywhere. Bathroom - fully-tiled, inc. floor - is not that warm, due to small towel rad. Kitchen same, due to small rad. Bed 3 rad doesn't heat up.

Rather than frig about doing workarounds before I get all of the replastering and redecorating done, I'd rather - when the winter is done - rip the lot out, have it all redone so that there are no "I wish I'd done that at the start" gripes and irks in future.

Fire-and-forget, in simple terms.

 

[Madrab]

OK, maybe I am reading your explanation wrong then, you are not planning to drop the 22mm down to 15mm and then use 15mm as the main flow and return to several radiators anywhere? All rads will be fed in 15mm with single branches to each one off the 2x22mm main runs?

In several places you mention - from 1 rad to another rad in 15mm - that's the part I'm picking up on. That sounds to me like you are using a 15mm branch off of the 22mm main loops to feed more than 1 rad, if so then that isn't ideal.

 

[Brigadier]

I was going to do as per the diagram, but then asked whether 22mm for all but the rad tails feeds (the 200mm bits to the valves) would be better.

Edited to change incorrect terminology.

 

[DP]

Pressure relief valve would need to be an auto bypass depending on boiler used.

 

[Brigadier]

Pressure relief valve would need to be an auto bypass depending on boiler used.

I'd leave all that to the heating engineer (if one wants the work). I was just getting some ideas on what are reasonable solutions to the piping layout, so that I can better judge any suggestions said engineer proposes.

 

[Madrab]

To have the best system with the quickest warm up times, easiest to balance and keep clean, the backbone would be kept to 22mm and only when the feeds branch out to each rad is it reduced to 15mm. I wouldn't use 15mm to feed more than 1 rad.

If the system is sealed it will have an individual pressure relief valve and, if required, an autobypass.