New Boiler ....Old Rads

[topgazza]

Just a general question if you like as to the best practice. Given a new boiler in a 27 year old system, unvented since 2006, powerflush and clean I suspect as standard on install should I be considering new rads as well given the age of the system ? I appreciate its subject to a case by case judgement, water colour and type of contamination, rust etc but in general is it something you guys would be looking at to include purely on age or isn't it a key issue ?

I guess its as much about rads last for a long time but like any component sometimes proactive is a good idea. Seems a shame to fit a shiny new boiler and not do this as a matter of course on such an relatively old system ? Especially if the technology/design of modern rads provides another increase in system efficiency and peformance.

 

[Mottie]

Well, there's no doubt new rads will be more efficient than the old ones and if you want to get the best out of your new boiler you should consider changing them. I've just recently had my open vented system converted to a sealed system and I had two of the original remaining three rads leak almost immediately. Mind you, they were from when the house was built in 1961 so they haven't done too bad!

 

[Agile]

All rads are 100% efficient! The heat you get out is the same amount of heat they take out of the system.

The only reasons for changing rads are:-


Old ones look dated.

New ones could give more heat output for the same size.

The old ones were undersized.

Old ones were sized for a flow of 80 C whereas new boilers are better with a flow temperature of 70 C. so in some cases higher output rads might be needed. [ That is usually balanced by energy saving which has been installed since the rads were fitted like double glazing and loft insulation )

Tony

 

[topgazza]

Thanks guys. Kind of what I thought.

No specific rule of thumb that says...30 years old rads ? Change 'em. Looking at mine, circa 1989 they look ok when painted and the wife doesn't like the "dust collectors" of the new ones with grills on top. Take them off them I say. I have added a couple of designer rads in the cloakroom and the ensuite because they looked prettier but thats probably it unless I feel a bit flush (no pun intended) when I do eventually come to fit a new boiler

 

[Mottie]

When I changed my 50+ year old rads for new ones, they were definitely much hotter to the touch than they'd ever been. Maybe it was 50 years of sludge and twenty coats of paint that was making the difference. Even though the new ones were slightly shorter, they were way heavier too (the replacement ones were shorter as I had to get the next metric size down from the imperial rads and use a pipe extender) suggesting the metal was thicker. Doesn't a thin metal radiator transfer heat quicker compared to thick metal one?

 

[ianniann]

If the old rads are heading towards the end of their lives then it would be the perfect time to replace them. If not, I wouldn't do it. With proper corrosion inhibiter through its life, a radiator should go a lot longer than 27 years, but with less care they could be tea strainers by now.

Suitably sized, the boiler will run more efficiently with new ones although I doubt you'll ever make your money back from the replacement cost alone. Of course, if you take the opportunity to replace with smaller radiators then you might not get the benefit of more efficient condensing in the boiler.

Motman, maybe your new radiators were solid copper. I bet they'd be hot and heavy.

 

[topgazza]

You'd think so, ref thin rads, wouldn't you as the whole purpose is to release heat stored in the water. Forgot about the coats of paint. Like motman I have an unvented system and the plumber did a good check for leaks post install and advised we check for a while around the house. None to be fair but I do have the thought if I have any rads that are only held together by paint. I have had a couple of rads with some surface rust on the outside seams due to leaks when bleeding running down the rad over the years or I assume so. But a good rub down, some red oxide sorts them out. Rad water is pretty clean when I do drain or bleed... I wouldn't drink it mind you

 

[Mottie]

Motman, maybe your new radiators were solid copper. I bet they'd be hot and heavy.

Oops! I meant the old ones were heavier. Made of pig iron I think!

 

[topgazza]

not kosher then ?