change radiators & keep DHW

[scholesy]

Hi All

I am about to start work on my central heating. I currently have a Gloworm Swiftflow 80, (12 years old), combi and a sealed system.

I am changing the rads and then paying a Corgi Plumber to install a new Combi (Vaillent ecoTEC 831).

My original plan was to turn CH off on boiler, drain the system, change all the radiators over the course of a few weeks. Flush the system with Ferox before having the plumber in to change the boiler and finish off.

Is it possible to have the CH side of the combi drained and still get hot water?

If not what would be the best way to do this? I need to keep the house supplied with hot water whilst trying to avoid to much contaminated water from current system being run through the new rads (although not sure if that matters too much as would only be a few weeks).

thanks for any advice
Andy

 

[jon26]

You should be able to drain the CH then cap it off whilst you use HW. No problem

 

[buck51]

If you drain it down,and cap it off how are you going to repressure the system?
Why drain it down ? Why not just drop the pressure while you change each rad in turn, then you could repressurise and vent each rad and check for leaks as you go
And no running around like a scolded c**k having to deal with several leaks at once,
If your not sure why not ask your RGI /Plumber How to go about it
I wish you luck, Its only water have fun!!!

 

[spacethegas]

if i were the rgi i would be unable to fill out the benchmark cert & register it as i could not guarantee the system had been treated & flushed as per mi or bs.

think of it this way. if a problem were to occur under warranty that the manufacturer felt was attributed to this and refused to rectify. who you gonna blame..................ghostbusters ?

 

[scholesy]

I'll be changing all the valves when I do the work and repositioning some of the piping due to different rad sizes and additional radiators.

Spacethegas would the system need as thorough a flushing if all new rads were installed?

I'll do as buck51 has suggested i think. I'll probably have to do a few complete drains (for ground rads\valves). I've no idea how long its going to take as I've never changed a radiator before. I may try and just do the lot ("8") over a weekend. Once the system is up, i'll put Ferox in for a week and then flush the system. The plumber doing the job is a good pro so if theirs any issues regarding flushing etc.. i'm sure he'll be aware of them and do the flush himself.

I was planning on using compression fittings for the CH pipework, would this be ill advised. Would this also be against building regs as they'll be under floorboards?

cheers for the advice fellas
Andy

 

[spacethegas]

compression is ok.

you cannot flush too much.