Old Central Heating

[rob_j20]

Been browsing the site for ages, but its time to show my face.

Have an old central heating system that just doesn't get the house up to temperature, mix of old boiler, many layers of paint on undersized radiators.

I plan on doing the radiators and pipework myself and just getting people in to fit the boiler and connect up.
I'm starting in the master bedroom only with a new radiator and new pipework, the old is poorly installed, and makes loads of noise while running, no pipe supports anywhere.
I'm going to use Hep2o for the pipework done lots of reading up on it, 15mm to each radiator and 22mm for the main runs, 22mm copper for the first meter at least at the boiler.

I'm doing the first radiator soon as i have the floorboards up already, and plan on not connecting it up until the rest is all replaced, i though it might not be a great idea to start pumping the old system water through a new radiator, it has no inhibitor at all and even after draining a few times still comes out dirty.

Radiators i like the look of the Stelrad Vita Eco ones.

Learnt a lot from just reading this forum, about system temperatures and keeping the return flow under 55ish C. I'm going to oversize the radiators as much as possible and run the temp on the boiler as low as i can, want Honeywell Evohome for the best control and weather compensation.

 

[Aquaheat]

Good to know.

Was there something you wanted help with?

Jon

 

[rob_j20]

Good to know.

Was there something you wanted help with?

Jon

Just hoping i'm not making any mistakes, or if there are any other ideas. I didn't think it would be a good idea to start pumping the current water through new radiators, and didn't fancy using any cleaning products ive heard they can cause issues on really old systems that have not been maintained.

One thing i'm not sure on, is it worth insulating the pipes that run between the suspended floor/ceiling, i will be doing the ones on the suspended ground floor.

Over-sizing radiators is it an issue?

 

[Aquaheat]

Can't give ideas without details.

On what you have said its a good idea that you arent connecting new to old.

Rads are a personal preference but as a manufacturer then Stelrad are OK.

Plastic is fine just make sure its secure. Oh and PLEASE, PLEASE, PLEASE use copper to the rads. It just looks so much better.

1m from boiler is good. Well done for reading MI.

Rads should be sized to each room. Delta 20C loss. You'll never be 100% but don't oversize massively. New boiler will modulate for return temp.

Evo home well..........................best to ask people that know. I've never fitted it others have and work most of the time others have issues. It seems flaky. I'll pass that to @Dan Robinson @simond @LeeC

Jon

 

[rob_j20]

Thanks.
I've been using this calculator
http://www.theradiatorcompany.co.uk/heatoutput/
and adjusting to 70/50/20c so 40t going on Stelrads specs. I think that's right, i understand most specs are based at 50t.

Plastic securing wise i plan on putting a clip or such every half meter, i will either be using copper tails or chrome, not decided yet. (I understand i need to use compression for chrome)

All current radiators are single panel and even with the boiler on its highest setting, the thermostat set to 20c, it rarely gets to the point where it cycles on and off. Its an old system boiler as well, gravity hot water and pumped heating, i did some emergency repairs on it, the old tank was leaking so converted from a primatic tank to a indirect one, which required another expansion tank. The water expansion tank needed replacing as well that was leaking (old metal tank).