Cast-iron radiator restoration...

[NickG]

We are renovating a house in the Haute Pyrenees that has around 14 cast-iron radiators. I am keen to investigate the cost involved in having them reconditioned and the valves adapted for use as part of a new gas central heating system.

Does anyone have experience of having had this done in France or know of a company in Dept. 65 that can provide this quote?

Also can anyone comment on the relative efficiency of cast-iron radiators vs. modern equivalents?

Thanks

Nick

[Rodie]

Hi im a uk htg guy ,you could wash out the rads yourself and wire brush them and paint them too and save some cash,if you have them sand blasted by a company they must be painted the same day or they rust ,i had 2 small cast rads done and it cost me £130 ,i have just done another 2 myself in about 2hrs and just used car paint (met grey)

[Gluestick]

Some cast iron rads come apart in sections. If they are taken apart then they will need new gaskets/seals.

Simply washing them out will not necessarily achieve much, other than to displace the sludge that sits mainly at the bottom. The main problem with cast iron is rust corrosion, which reduces the free flow of water and prevents good heat dispersal through the casting and thus to the ambient air.

The level of inner corrosion would depend on how long they have been in service and whether anti-corrosion inhibiter fluid has been rigorously maintained. Old french house? Probably not.

Personally I would carefully examine the last rad in the circuit - as sludge tends to be carried along and the last rads sludge up more than the first  - and make a go/no go decision on that basis.

If the rads are well corroded, internally, then they would require chemical dipping to clean out the water ways. Not cheap. Most restorers include sand blasting and enamelling in their price.Beware "Restorers" who simply sandblast and make them look pretty! They need cleaning internally and pressure testing prior to commissioning. (Corrosion can create "Pin Holes" which will fail in short time! Cleaning and sandblasting can remove the surface paint and rust which has been sealing these pinholes up!)

Efficiency: modern rads have far more finning and surface area exposed to air and thus are much more effective heat exchangers. Additionally, materials such as aluminium have a far higher ability to conduct heat and are thus better as heat exchangers. For example the Thermal Conductivity of Aluminium of 4.5 times that of steel: and copper is 9.5 times that of steel.

Cast iron has lots of free carbon and is less effective at conducting heat than steel.

There area number of restorers on the web. It may well pay you to replace the old rads with new cast ally models.

 

[Bugsy]

Did all ours, sand-blasted painted and fitted each one with Danfoss valves. Well worth the effort if you have an old place.

[James]

Hello,

  We have 4 cast iron floor mounted rads. I bought 2 cast iron rads from an architectural salvage place for 80 euros and asked if they leaked. They said they didnt and said they saw them working before being removed. They dont leak. We bought the other two from a friend.

  I pressure washed them inside and out and sanded the peeling paint off them and re sprayed them and then installed them using new trv,s and lockshield valves.

  We also have 9 other new modern steel convector panel radiators and find the cast iron rads far nicer to look at and the heat output superior.

 We have 3 installed in our 34 square metre living room  3.4 metre ceiling height and at the moment here in Normandy find that 2 on thermostat position 3 is enough to heat the room.

  I would definately keep your old cast iron rads as they are a characterfull asset to your house. They are very expensive new.

  If none leak and all heat up well I  would drain heating system down, re fill then heat them back up again  and re drain and re fill using fernox anti corrosion inhibitor. If some of them leak at the castings I would replace that rad for another.

  Please please keep them.    James.

[Gluestick]

Remembering, of course, that if you buy (or have) a number of identical rads of the modular type, you can take them apart and build one good one up from two, e.g.

On that basis, even one which leaks, can act as spares for others, so don't bin it.

 

[The Builder.]

Hi. Just a few pointers. If they're ornate, don't think of replacing them.Can't help with 65 I'm afraid but if it's any help, rely most on the pressure test. If they fail it's not really cost effective to continue but you can split sections and renew gaskets  if the rads are a  matching set. As they're already part of your system there's less risk compared to buying second-hand.If you want to save money and are strong, de-commission them yourself get them outside, get the hose on them and up to 3 bar.Fill them with a good de-sludger (e.g Sentinel) and let them soak.Pressure wash them internally if possible or get an air line through them at least. Then think about restoration.Personal preference here but french method tends to diagonal flow and return. Swap fittings / bottom bushes if you're doing new pipe runs as well. This can be tough if corroded. You may need heat and the right tools.The best is blasting by someone who's done rads before and immediate powder coat (cheaper finishes can smell for a long time afterwards) and make sure they know not to bung up the bleed valve etc. Definitely Danfoss. I wouldn't want to pay more than £50 per rad for blast and coat for a big job lot but I would go a bit more, depends if you can transport them etc. As for efficiency no-one I know would swap.

[NickG]

Thanks to everyone who replied - very useful info, and the concensus seems to be keep them.

I had also emailed a request with photos to a radiator specialist I found on the web in Paris. He says the majority of the radiators are made by Chappée. They do not appear to be modular, and are not ornate. They have the diagonal flow and return described by 'the build doctor'. I think most UK restorers would refer to them as 'school radiators', but I really like the look of them. The house is only 1960's chalet style and I don't think the heating system has been used for 8 - 10 years.

They are all wall-mounted, and having already taken 8 - 10 spare ones out to put in the garage, I can confirm that it will be back-breaking work to remove the remaining 14 (some on the 3rd floor) for reconditioning!

Subject to what our plumber says when he quotes for the heating install, I would really like to give them a try. Can anyone who has restored their own rads recommend a national chain from which I can hire/buy decent sand-blasting kit?

If I'm looking for a local restorer, what category should I look under in Pages Jaune?

Finally, how do I calculate the size of cast-iron radiator needed for each room, as we're knocking some walls down and dividing other rooms up, so the radiator currently in situ may end up being the wrong size! With number of varying sizes throughout the house and in the garage, I should be able to match the appropriate rad to the new sized rooms!

Thanks Again

Nick

[Gluestick]

If you look here: http://www.burnham.com/pdfs/htghelper.pdf

You will find one of the most valuable CH resources on the web. Look at page 42.

Good sand blasting equipment is quite expensive. Needs large compressor. Better probably to find either a mobile blaster who can do this in your garden or can take away and return.

The earlier comment about powder coating is very sensible! Good advice. Paint pongs when it becomes hot! For quite some time.

 

[The Builder.]

You could try ringing radiateurfonte.com and pick their brains as they source throughout France........

[NickG]

Thanks for the tip, but Eddie Coencas from radiateurfonte.com was the specialist I mentioned above that told me the radiators are made by Chappée. He has emailed again to suggest that I get them restored locally by looking in Pages Jaune under the category 'décapage', as he favours dipping over sand-blasting, to avoid the risk of making small holes!

[Deauville]

Great things old radiators - or they would be if the chaufagiste turned up to instal them and the chaudiere!!!Does anyone know anywhere in 24 (we're just in it being beween Bordeaux and Bergerac) where I can get cast iron radiator feet and support brackets? Joyeux Noel to all