Anything is possible with running a modern boiler on an old system. Micro bore was the ‘cheap’ alternative to installing a central heating system as the price of Copper piping was so high. It is still installed today, albeit on a lesser scale than before. You are more likely to encounter problems with sludge / lack of circulation in a micro-bore system. Also, if you have old radiators, it could be possible that they wouldn’t be compatible with a modern combi. As for splitting the pipes, that is dubious. Modern combi’s normally operate between 1 to 1 1/2 bar. However, the maximum operating pressure before the pressure relief valve kicks in is 3 bar. Older system boiler do not work on these pressures. Soldered joints on any central heating systems (if installed correctly) should be able to withstand the modern pressures.
Steve (Gasman)
the boiler they installed was a Glow-worm 24hx model condensing version if tfhat means anything
RE en-suite
I bow to your greater knowledge as I don’t have a clue. Just as a bye the bye when they took off all the old wall tiles (tiles on top of tiles double thickness) and ripped out the French all singing and dancing shower unit they found the original pipes in the wall, obviously disconnected as the French unit was fed from above. most parts didn’t work either because the French pipe threads are different to ours
Again the previous owner went to France and bought it back without checking first if it would connect up ok
the feeds for our heated towel rails below
glad i took several photos at the time
old French unit ripped out
one we had installed
Hi Steve,hope all is well,its a Gloworm ultracom 24hxi,just checked print out again,98% net,89% gross.
https://i.imgur.com/PI8bXna.jpg
Spot on.
Yes, we recently invested in Hive. Quite a reasonable price from Amazon and included thermostat, receiver and hub.
Our old controls included a room thermostat with which we could adjust the temperature, but the on/off times had to be adjusted on the boiler which is out in the garage - an inconvenient trek out the front down the garden path and back up the drive which was not very nice in the cold winter weather!
All can now be done from the Hive thermostat, or our mobile phones anywhere with an internet connection.
Yikes… microbre.:shock: I always refused to touch it. It was so fragile and the manifold was always somewhere where you couldn’t get to it. 
Good call and let’s hope that it is just from the condense pipe.
@realspeed the boiler they installed was a Glow-worm 24hx model condensing version if tfhat means anything
Nothing wring with that boiler RS, as long as you have an annual service, it should be fine. The efficiency is about 88.2 % A point to remember about the boilers condense pipework. Ideally, it should be run and terminate indoors if possible (into the sink waste etc) if it does run outside, make sure that it is insulated well. A frozen condense pipe could(and normally does) prevent your boiler from working.
A Hive control is very good, as are some of the competitors. At least you don’t have to go outside to adjust the heating now JBR:-)
That amount of radiators and towel rails is pushing your boiler to its limit. I wouldn’t be surprised if it isn’t running flat out all of the time. A 30kw boiler would have been better.
Nothing wrong with those readings Caricature and yes, I am OK thanks. Hope that you are too.
I agree LD and normally, if the system is ‘sludged’, you can’t have a powerflush.
Talking of which, we have one room supplied by microbore - the conservatory. As I understand it, it is illegal to have a radiator in a conservatory attached to the regular heating system in the rest of the house - I think!
On the other hand, we rarely have that radiator turned on, as it’s rather pointless. In summer it isn’t needed and in winter it wouldn’t make much difference, not that we use the conservatory in the winter anyway.
Ah! So is the only solution to replace the radiators affected?
I must admit, I have never heard that one before. As for being illegal, I assume you mean against the ‘rules’. Gas Safe ‘rules’ do not apply to anything else apart from gas.
I can’t remember where, but I think I read it somewhere some time ago.
It doesn’t matter, though. I don’t stick to all the rules!
If most of your radiators are OK, you could replace just the ones that are causing problems / rusty. In which case, you have two choices.
- Drain and flush the whole system. Replace rads and defective valves. Refill the system, add a cleaner, run the system as recommended by the manufacturer. Drain, flush and refill the system. Add inhibitor.
- Exchange radiator(s) add cleaner. Drain and flush - add inhibitor.
Personally, I always prefer No1.
Yep fine thanks,thanks for the boiler reply.
Thanks.
Thanks. That’s food for thought.
If no. 1, does that mean you drain and flush twice, or have I misunderstood?