Old cast iron column radiators flow return-urgent help

Unregistered · Oct 31, 2015

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

village idiot · Oct 31, 2015

Welcome. If you can try and register with the Forum, then chances are someone may help with the issues you have!!!!

SimonG · Oct 31, 2015

Tboe.

Elli · Oct 31, 2015

Now registered 🙂

SimonG · Oct 31, 2015

Top Bottom Opposite End

Flow to top and return to bottom

Oh and welcome to the forum 🙂

village idiot · Oct 31, 2015

Top (flow) bottom (return) is ok. If you can do the flow and return at bottom, that's also ok.

Elli · Oct 31, 2015

Thanks Simon-so would bottom -bottom not work do you think?

Elli · Oct 31, 2015

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?

Elli · Oct 31, 2015

This is a pic of one of the bigger radiators

SimonG · Oct 31, 2015

Bottom and bottom is fine. If you can get the blanking plugs out!

SimonG · Oct 31, 2015

Have they been pressure tested?

Elli · Oct 31, 2015

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!

Elli · Oct 31, 2015

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.

Elli · Oct 31, 2015

Thanks for replies everyone-will go with the bottom-bottom

Elli

WaterTight · Oct 31, 2015

Elli said:
strangely rewarding when they budge 🙂

Isn't it though!

Like popping a million bubble-wrap bubbles at once.

ShaunCorbs · Oct 31, 2015

how big is the property (how many bathrooms)

village idiot · Oct 31, 2015

ShaunCorbs said:
how big is the property (how many bathrooms)

??? Are we on the same topic Shaun?

ShaunCorbs · Oct 31, 2015

village idiot said:
??? Are we on the same topic Shaun?

just a bit of a left turn but normally property that are able to handle cast iron rads tend to be big just questing why the op went with a combi thats all vi 🙂

oz-plumber · Nov 1, 2015

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

jtsplumbing · Nov 1, 2015

They look a bit rough, wonder how much rust is inside them?

rpm · Nov 1, 2015

SimonG said:
Have they been pressure tested?

I would do this first before going through everything else then finding leaks.

stevetheplumber · Nov 1, 2015

top botton opposite ends will give more output

WHPES · Nov 3, 2015

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.

chris watkins · Nov 3, 2015

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

ShaunCorbs · Nov 3, 2015

chris watkins said:
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

Elli · Nov 4, 2015

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

ShaunCorbs · Nov 4, 2015

Elli said:
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

Elli · Nov 4, 2015

Fittings

JTM Brass flanged plug-threaded brass
1"
1.5"

JTM Brass hexagonal bush
1.5" to 0.5"
1" to 0.5"

ShaunCorbs · Nov 4, 2015

Elli said:
Fittings

JTM Brass flanged plug-threaded brass
1"
1.5"

JTM Brass hexagonal bush
1.5" to 0.5"
1" to 0.5"

i would try and get the blanks and bushes in steel if you can

Elli · Nov 4, 2015

so kind of like use the hacksaw to notch the thread that's stuck in then try and sprise it out?

Elli · Nov 4, 2015

on the JTM website if its described as galvanised is this steel? Are these more hard wearing?

thanks

ShaunCorbs · Nov 4, 2015

Elli said:
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

ShaunCorbs · Nov 4, 2015

Elli said:
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

Elli · Nov 4, 2015

In galvanized they only have a 'galvanized hollow plug' that has like a square bit on the end-would this be ok?

rpm · Nov 4, 2015

Elli said:
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.