kinked, crimped and coiled 8mm pipework

[1animal1]

Hi,

I'm after a little advice.

I am working my way through a renovation of my central heating system prior to new carpets being fitted in the next few months and an unvented cylinder conversion from my current vented being fitted in the next year or so - this will be moved from the 1st floor airing cupboard to the ground floor garage. I could ideally do with getting the new system in before new carpets but I have a wedding to pay for in July which is scuppering my plans so right now the priority is to do as much as possible to convert fully to 15mm and replace T&G floorboards where possible that have been hacked by previous fitters (also to lower pipes to prevent banging on the boards when stood on) . This should mean minimal carpet removal when the new system eventually gets fitted.

As I start prep work, I've been lifting a few floor boards to get an understanding of the layout and what I'm faced with. My current set up includes 13 rads (approx 35-40k BTU, yet to calculate accurately), of which 7 upstairs which are the ones getting sorted first - 4 of which have 8mm pipework which I'm not comfortable with given it has been installed for at least 2 decades and has taken a lot to get it running clean again, obviously nothing added to prevent corrosion (average run is 8 meters to each rad from the landing). My plan is to run 15mm push fit from the 22mm feed/return running along the landing, fitting copper risers to new TRV's. My plumber also wanted me to run some pipe to the en suite mains shower for a direct hot water feed from where the unvented will be situated.

The system seems to have a main feed from the kitchen boiler (downstairs), going upstairs to the middle of the house where the cylinder lives, this then splices above the pump (next to the cylinder) into the electric valve which feeds the rads and hot water coil alternately. From what i can see so far i have 2x 22mm pipes for the rads, one which is the colder of the two on my working system, I assume is the return, this runs along the landing returning to the boiler with a T in the middle feeding downstairs, along the way it has the returns from the various rads - the other 22mm pipe (feed) appears to run halfway along the landing and downstairs again feeding into the rads along the way.

My question at this point is a strange one - when lifting one of the boards near the cylinder i noticed several wide coils of 8mm copper pipework from both of these feeds to 2 of my upstairs rads - not only are they coiled at least twice under the floor, they also appear to have been almost squashed fully by pliers in several places, presumably to reduce flow - why would this have been done? i presume to reduce flow perhaps, but isn't that what the lockshield's are for?

I don't really want to remove this and replace with the 15mm until i know why it's been done.Can anyone help?

Thanks

Tim

 

[ShaunCorbs]

The worst case I have is 4 rads off one 22mm branch, medium sized k1's. And one 800x400 towel rad.

Would I be good reducing to 15mm with a straight push fit, then a series of 3 15mm T's immediately after to save cost. Or would you recommend a series of 22mm reducing T's in line

Edit: I'll try and upload my drawings of the upstairs pipe run later, to give bit more perspective

22mm ts

 

[1animal1]

Cheers Shaun, much appreciated :coffee:

I gather it won't make much difference to the flow if I use the end of the last T for the fourth feed, or should I cap this

 

[jtsplumbing]

What could be of use to you and would answer a lot of your questions, Go on to CORGI web site . & purchase a copy of ( Wet Central Heating System Design Guide.)

 

[1animal1]

Thanks for the suggestion JTS, isn't that a bit overkill though given the fact that I'm making some minor adjustments to an already installed system and asking some relatively basic questions.

I thought I'd use a forum to gain a bit of advice which is what it's here for is it not?

 

[jtsplumbing]

No it has some good illustrations and is easy to understand, even covers unvented systems just thought it may help you understand how different systems work, Think it gets handed out to guys doing plumbing & Heating course. used to get a heat loss CD so that you can work out rad sizes.

 

[1animal1]

Ahh OK, I'll have a look at that... Thanks for the heads up

 

[ShaunCorbs]

http://bpec.org.uk/downloads/CE30 - Domestic heating by gas.pdf

 

[jtsplumbing]

There you go, even better its free :book: thanks to Shaun

 

[1animal1]

Extremely useful read... Thanks chaps. I have done a bit of independent reading too on star systems and the benefits of single pipe loops, feed and return and microbore systems prior to settling on the unvented. My plumbers initial advice was a large combi, but the need for high pressure hot water to the en suite, maybe eventually the main bathroom and possibly a second en suite if I get around to building it - he agreed that the unvented was the way to go.

One thing that was a concern was the suggestion that a feed and return system can handle roughly up to 12 rads, where I have 13. This is why I'm thinking of extending the feed so that it can be accessed by the new boiler more directly, than having to access the feed through the old pipework, running 7 metres of 22mm before it gets to the feed pipe

 

[PhoenixServices]

I think I see what your saying about the new direct 22mm run instead of going to the old airing cupboard. As all the pumps and valves will be down in the garage I would of thought.
Can you upload a drawing just to double check we are on the same page.

 

[1animal1]

Will do, I'm going to put it together again before posting, to give it some scale. Currently the pump and electric switch for the hot water/rads reside in the airing cupboard, but they will be in the garage with the new set up... The diagram will show everything

 

[1animal1]

This is the best i could knock together, apologies for the messy writing. All rads are fed by the 8mm manifolds apart from the bedroom above where the boiler sits - these two rads have a 15mm run to the tail of the main rad feed - all pipes on this map are the 22mm main feed, 22mm rad feed, 22mm rad return and the hot water return from the cylinder coil which taps into the rad return.

The airing cupboard house the vent pipes, the pump and electronic valve.

I was proposing putting in place a 22mm pipe to meet the rad feed which stops at the top of the stairs - the new boiler/cylinder will be in the garage which is on the same wall as the current boiler. The main feed and hot water return can then be removed from the system once the new system is in.

 

[jtsplumbing]

Is there any reason why you cant reposition radiators ? the bottom 3 seem a long way from main pipe runs, new radiators don't have to be under windows,

 

[1animal1]

They are pretty long runs. The main bedroom definitely can't be changed as the rad sits in a bay window , the rest of the walls are taken. Ironically this is the longest run at about 5 metres.

The two smaller bedrooms off the landing could be looked at, but the run is already in place and the only thing I'm saving is a few metres of pipe.

I was going to ask about the bedroom above the boiler, it has two rads connected via 15mm to the 22mm rad feed. Obviously if I extend the rad feed then these rads will have their pipework reduced. But I can't help but think that if I remove the furthest small rad it'll remove unnecessary pipes and joints... I'll measure the rooms/windows/rad sizes and post up if that would be useful as a gauge?

 

[jtsplumbing]

Are all these rads fed by 8mm pipe, maybe you could extend 22mm to rad in big bedroom then 15mm along into other 2 bedrooms keeping inline with rads if you don't want to re-site them

 

[1animal1]

Yeah, they all 8mm bar the two in the end room. Because I'll be laying the pipe to that end room for a more direct boiler feed, then it would be very easy for my plumber to tie in the larger rad above the boiler, removing a good few metres of pipe as that rad would be on top of the new extended 22mm feed.

My only concern is the size of that room. It's 6.5x2.6 with a k1 600x1100 directly opposite the door, in the map it's slightly off as it would have obscured the boiler. It also has a k1 600x600 under the window

The window is only 1m square.... Double glazed

 

[jtsplumbing]

Usely find radiators under windows a waste of time, people tend to cover with curtains, can you not do away with this rad and upsize the other one

 

[1animal1]

Yep definitely, that was going to be one of my questions eventually what I might do is lengthen the 22mm feed, tapping into that with the enlarged rad, and then cap the 22 off where I know my plumber will be jointing above the new boiler. That way I can install it all now for minimal disruption when he comes.

What would you do re this rad in the large room? Change to K2 similar size?

 

[ShaunCorbs]

Best to work the room heat loss out and add 10%

 

[1animal1]

No probs, I found a good link for a calculator, will give that a go.

 

[ShaunCorbs]

Yea there's a few out there just do more than one and compare results

 

[1animal1]

I see what you mean, I've tried 3 so far, 3200, 4200 & 3700btu!

 

[ShaunCorbs]

I see what you mean, I've tried 3 so far, 3200, 4200 & 3700btu!

3700 btu just over 1kw is the average

 

[1animal1]

Thanks!

I didn't expect them to vary that much!

 

[1animal1]

Upon closer inspection of one of the manifold's, it appears that 2 of the 4 branches double back to the return manifold. Therefore the massive crimping session that's gone on is obviously to reduce flow, but leave enough for it to act as a relief valve.... I was under the impression that the way to add a relief valve was to fit at least one rad with no trv, only lockshields?

 

[ShaunCorbs]

yes on full systems you have two choices either fit an auto bypass or fit one rad with lockshields ie normally a bathroom

 

[1animal1]

So him crimping a bypass pipe constitutes an auto bypass or have I had bodge it n scarper fit this system?

 

[ShaunCorbs]

So him crimping a bypass pipe constitutes an auto bypass or have I had bodge it n scarper fit this system?

if theres no valve on it they have bodged it

 

[1animal1]

I haven't discovered one yet. Where's the most likely place for one?

 

[ShaunCorbs]

I haven't discovered one yet. Where's the most likely place for one?

should be on the 8mm if there is one

if not put a auto bypass on best place would be after the pump but before the motorized valve and in 22mm