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Old cast iron column radiators flow return-urgent help

View the thread, titled "Old cast iron column radiators flow return-urgent help" which is posted in UK Plumbers Forums on UK Plumbers Forums.

U

Unregistered

Hi there

I wondered if anyone could help quite urgently as rads get piped in tomorrow and I have a lot of conflicting advice.

We are restoring an old property at the moment which had no central heating. We are putting in modern combi and old reclaimed cast iron column radiators. Some are quite large. We are using these valves

Premier Traditional Angled Radiator Valves | Satin Nickel | Online Now

Some rads have

inlet at top/ outlet at bottom-opposite ends

inlet at top and outlet at bottom-same end

We were going to pipe: flow in at bottom and return at top as we were told the hold water would rise to the return?

I have since read that putting flow at top is best as water cools it will fall to return? Felling really confused?

I also read that bottom to bottom is ok for flow and return? Aesthetically would prefer this and would avoid us having to plaster in pipes chased in channel for top? Would this be ok if we balance the rads properly. Flow is in 22mm branched in 15mm just before each rad.

Just want uniform heat across the rads? Do you think if we do bottom to bottom and restrict return they will have time to get hot on all the sections?

Any advice very much appreciated 🙂
Elli
 
Ok so if I did bottom-bottom and just switched the blanking fittings to top that should be okay? Would I have to try and balance red to get uniform heat?
 
Ok great-got Dad's big wrench and a very big piece of steel pipe-stubborn but strangely rewarding when they budge 🙂

Thanks for all your help!
 
Not yet-but have come out of old school/ some out of old house. Keeping my fingers crossed all will be ok. We flushed them with hose.
 
A problem you may encounter is that the end fittings have left & right hand threads.

Rads that have the connections on the same side, you will not be able to swap to the other end because the directions of the threads will be different.

Have you any spare gaskets? You may need some if you are removing end fittings
 
Would definitely say top flow bottom out for cast iron. Don't pipe both at the bottom. Any plumber worth his salt can make it neat by putting bends in the pipe to discretely drop it down behind the edge of the radiator.

Don't do bottom in, bottom out on cast iron.
 
These rads are not designed to work at 3 bar pressure which is the safety valve setting on your combi.
They have spent there lives so far in open vented systems with a head pressure of a floor or two i.e. 0.6 - 1bar.

If I were you I would be testing them first as SimonG suggested, then I would fit a safety valve with a lower setting to the system!

BTW - TBOE for the con's
 
These rads are not designed to work at 3 bar pressure which is the safety valve setting on your combi.
They have spent there lives so far in open vented systems with a head pressure of a floor or two i.e. 0.6 - 1bar.

If I were you I would be testing them first as SimonG suggested, then I would fit a safety valve with a lower setting to the system!

BTW - TBOE for the con's

or run it on its own plate heat exchanger
 
Hi everyone,

need a bit of help again please with a couple of problems

So we had x20 radiators and we managed to get the cap-end/ valves off x18 of them to swop and do the bottom-bottom flow/ return.

Then problem 1 developed 🙁 Unfortunately- we managed to shear the valves clear of the remaining 2 using our big trusty steel pipe :S and the thread is now stuck inside. We have tried gently sawing to try and loosen/ hitting with a chisel and drilling but they won't budge. Does anyone know how to get these out other than praying for a miracle! We were going to try a steel merchant/ welder and see if they can drill them out?

Problem 2 is some of the fittings are in pretty rubbish condition so I don't know whether to get new. For some radiators its 1.5" opening and others its 1" so I was going to get these reducing bushes to fit our 15mm valves and put new stop ends on-are these the right type?



Also been advised to use LSX sealant when fitting the stop ends-is this the best one do you think?

Thanks-any advice much appreciated 🙂
Elli
 
Hi everyone,

need a bit of help again please with a couple of problems

So we had x20 radiators and we managed to get the cap-end/ valves off x18 of them to swop and do the bottom-bottom flow/ return.

Then problem 1 developed 🙁 Unfortunately- we managed to shear the valves clear of the remaining 2 using our big trusty steel pipe :S and the thread is now stuck inside. We have tried gently sawing to try and loosen/ hitting with a chisel and drilling but they won't budge. Does anyone know how to get these out other than praying for a miracle! We were going to try a steel merchant/ welder and see if they can drill them out?

Problem 2 is some of the fittings are in pretty rubbish condition so I don't know whether to get new. For some radiators its 1.5" opening and others its 1" so I was going to get these reducing bushes to fit our 15mm valves and put new stop ends on-are these the right type?



Also been advised to use LSX sealant when fitting the stop ends-is this the best one do you think?

Thanks-any advice much appreciated 🙂
Elli

you will need to hack saw very carefully a slot out about 1/2 inch so you can then fold the snapped part inwards and boss white and hemp to put the new stop ends in
 
so kind of like use the hacksaw to notch the thread that's stuck in then try and sprise it out?

yes but dont cut too far (into rad threads) and cut it top and bottom and then either side and you should be able to work one out then the rest will be easy only prob it takes ages
 
on the JTM website if its described as galvanised is this steel? Are these more hard wearing?

thanks

well in your post you said brass the only prob with brass is its soft so might cross thread
 
so kind of like use the hacksaw to notch the thread that's stuck in then try and sprise it out?

My method is to two cuts one at 12 o clock and the second at 10 o clock, once that segment is out then hammer & chisel at 12 o clock towards 10 o clock and downwards, this should take the pressure off the fitting and it will come out by hand.

This is for a right is tight thread.
 
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