odd system design ?

[geeeman100]

I've been in my 1970's house for 5 years and the heatings never been great but the hot water taps are ok.

I often have to bleed the rads and the pump is quite noisy. I noticed slight leaks around the pump so have fitted a new one but not made much difference. Looking around the system I have found something which doesn't make any sense at all. It is an open vented system (think thats the name - with a header tank in the loft).

There are 4 pipes from the boiler, 2 for the hot water for the taps and 2 x 22 mm ones for the heating. The pump is on the return. I've found a manifold underneath the floorboards upstairs with a 22mm pipe at each end and 16 x 8 mm pipes branching off.

There are 8 rads in the house and this manifold seems to supply both the feed and return for each rad which doesn't make sense to me. I can turn all the rads off except for 1 and one of the small pipes gets hot and then you can feel it returning through another which gets warm.

The fitting of these pipes to the manifold is random rather than the feeds being on one side and the returns on the other. Can any one shed any light ? At the moment I can only have a couple of rads on at a time to be effective.

Thanks

 

[fatplumber]

You have a microbore system. The flows and returns from each rad should connect to the flow and return manifolds from the boiler. This was a common system in the seventies. I hope that the other two pipes from the boiler go to the cuylindr and not to the taps as you imply.

 

[mickyg]

you can get a manifold that combines the flow and returns in one, I've never seen one but I'm aware of them and someone on here will probably know what I'm rambling about and hopefully explain in more detail
I believe the order of pipes are not as obvious as you'd first expect, similar to what you have discovered.

 

[Biggles..]

you can get a manifold that combines the flow and returns in one, I've never seen one but I'm aware of them and someone on here will probably know what I'm rambling about and hopefully explain in more detail
I believe the order of pipes are not as obvious as you'd first expect, similar to what you have discovered.

We know them as Hedgehogs, sure somebody else will call them something different.

Only time we now see them is to cut them out.

 

[geeeman100]

Thanks for the fast response you 3.

I didn't describe it right big man - the hot water's as you said thankfully. There is only 1 manifold so it must be a hedgehog - you've answered my next question - are they sh1t !!?? and icgs has answered that - thanks. What do you normally replace them with ? As a side issue are they notorious for getting air locks aswell.

Cheers chaps

 

[doitall]

The manifold consists of 8 flows and 8 returns with a blanking disc between them, they work very well, or as well as 8mm or 10mm heating system will.

It's not the manifold thats crap geeeman, it.s the system which is probably sludged up and will never work properly until you stop the air getting in and clean the pipework.

In this case blame neglect not the system.

 

[geeeman100]

Do you think this idea would be feasible:

get rid of the hedgehog, get 2 separate manifolds, 1 for the feeds and 1 for the returns with the feeds being earlier in the system, and having a smaller diameter pipe between the 2 so the hot waters easiest route is through the rads if a tstat is open but the water can still flow if they're all shut ?

Tell me straight if I'm being stupid please.

Thanks

 

[geeeman100]

thanks do itall - i hadn't seen your reply before i typed my last one. The system has been neglected and I suspect there may be a degree of blockage. I didn;t know regular servicing was needed so my fault and maybe the previous owners aswell - do you think a powre flush would help ?

 

[doitall]

I won't say your being stupid, just because you didn't understand my post, not many people do understand what I say ask the experts

You already have two separate manifolds, they just happen to be joined in the middle.

If you want to improve it the first thing to do is flush every pipe out one at a time.

A better plan is to re-pipe the lot.

 

[geeeman100]

anyone know of any links to pics of these hedgehog things ?

 

[doitall]

Kin heck.do a google for.

Yorkshire WM8 microfold or WM 12, or WM 18 thems all the sam with more ports.

 

[advancedplumber]

the problem is with microbore is that the smaller bore pipes can only can a certain ammount of heat. if radiators r upgraded over the years and larger convecter ones installed then 8 and 10mm pipework won't carry the heat to them. there is a whole calculation which consutant enginers do when designing heating systems and it all depends on the how factor. ie. how long the runs r. how many bends do the run include. how well insulated the pipes r etc. add these factors to the fact the pipes r clogged up. if r system hasn't been changed since then i can only imagine that the whole system is clogged and needs a good flushing out. on one job we put one of those power flush treatments into a an old and badly sludged system. we followed all the instructions as per. turned out the rust an hard sediment was the only thing holding the rads together and and approx 50 % of the rads pit holed(small leaks everywhere) being an industrial plumber i have only seen a system where there is a flow and return going to the same mainifold, but that works differenly to a domestic one. i would of though there should have been a separte flow and return manifold as i don't understand how the pump would circulate the water??? i have never claimed to know eveything so heres something new for me.

 

[doitall]

AdvancedPlumber.

They are two separate manifolds, they just happen to be joined together.

8 on one end are the flows, and 8 on the other end are returns with a blanking plate in the middle.

 

[kevplumb]

try disturbing them fella they disintegrate

bleeding spark was only wiring the stat

 

[advancedplumber]

ah gotcha doitall. never seen that done that way b4.