Replacing old radiators

Sin_Chase

Sin_Chase

Sin_Chase

Soldato
Joined
13 Jan 2004
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Got a gas fired central heating system and have got some quotes to replace the radiators. They must be 30-40 years old. They still warm up but they resemble radiator cores out of of a car rather than modern panels. They are seemingly single panels of some of description with no convection fins.

I think they were designed to be run 24/7. They look tatty but no real cold spots etc. I'm mindful that efficiencies have increased but the question is - is it wortwhile? The main catalyst is even with brand new double glazing the house is still difficult to warm.

I'm looking to put double panel doubled convector models in. The steel thickness will obviously be less than these old behemoths but that should promote quicker warm up (and cool down).

Online resources are mixed bag with a majority of places stating anything pre 2000 is worth replacing. They've got a vested interest in sales though, being wholesalers / e tailors.

Any opinions or others who have done similar?
 
May be a good idea to google your current radiator and see if the hipster tree huggers are buying your style radiator to smoke thier cigars next too whilst drinking a named .”special” brew tea

Might be able to flog yours and replace with good ones
 
Doesn’t matter on age. Not sure what you mean by efficiency it’s simply thermodynamics and heat transfer. If it’s too cold now either increate the delta T. Or increase the surface area of the radiators (double panel rather than single)

I had similar issues on old rads. Bigger rads always better, you can run them cooler which helps the boiler run more efficiently too by getting them into condensing mode.
 
Already running the boiler slightly above the recommended temperature.

Will work out the house and room kW requirements and then see what radiators I need. Think it's a case of not getting the required out from the existing rads. Should get the IR thermometer out and compare the feed and return temps.
 
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Well getting bigger rads will let boiler run more efficient which will be a thermodynamic win.

If you use trvs too then the rads can’t really be too big (if you are sensible )
 
Speccing up TRV4s and will probably oversize the rads. Comparing the prices of double panel/singled convector and double panel / doubled convector.
 
I recently had all the rads and boiler replaced in our Edwardian semi. The old rads were panel rads, but did not have fins on them (ie not convector rads).

In rooms where we had double panel rads, they've been replaced with Type 22 (K2) and where there were single panel there are Type 21 (P+). We also had a plinth heater added to the CH circuit; https://www.plumbnation.co.uk/site/smith-s-space-saver-ss7-fan-convector---kitchen-plinth-heater/ (and also a hipster cast iron column radiator because we're very hip here (actually, it suits the house!)).

I calculated what BTU was needed for each room, and then spec'd a radiator that can heat that room but at lower flow temperature (delta T30, rather than T50). This has worked well, and the house warms up quickly and then the boiler flow temperature is modulated - the radiators remain warm but the room temps are stable. (This is helped by the thermostat and boiler supporting OpenTherm; meaning that as the thermostat reaches target temp it can ask the boiler to reduce temperature rather than relying on the boiler to module based only on return temperature).

I am curious about your existing rads though.. take some pictures! You could 'cheat' and add fans to them to increase their heat output.
 
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Did some temp probing tonight. Boiler feed is 62 Deg C and return is 56.6 Deg C. The ambient room temp is around 18-19 Deg C.

Radiators are barely taking any heat out of the feed seemingly. I'm also over the ideal 55 Deg C return for condensing.

Im going to the reduce pump speed from 3 to 2 and see if I can decrease the return temp for the time being.

This is what the existing rads look like :

old_rad_0.jpg

old_rad_1.jpg
 
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Wow, not seen those before. Are you in the UK?

I'm not joking about the fans, that will help until you get them changed.
 
No real leccy hook ups near the rads. It's not TOO cold yet soo hopefully can get rads with more output installed before it gets proper cold.

The rads are clearly not matched to the boiler. The input temp is as near as damnit the same as the output on each rad. Less than 2 degree variance.

As for the not seeing before, I am in the UK. It wouldn't surprise me if they are French. The flat extension which was built around 30 years ago had a load of mental French wiring and other oddities. The radiators predate when the house came into the family, which was 1986..so at the very youngest 32 years old.
 
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I can't even find something remotely close when Googling to get an idea of what they are. I'll double check what material they are but don't think they are copper.

Edit - Not copper :p
 
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