Can my boiler handle it?

[buraddo]

I have an old, but well running, Worcester Bosch 240 in my 500-600 square foot flat (ground floor, 1 bedroom, South facing, old Victorian property with an accessible crawlspace).

It is always cold in the winter and I think I've realised why. All of my radiators are the flat, single panel style. Rough calculations using online tools tell me that I've only got about 50-70% of the BTU output that I should for the room sizes.

I want to upgrade my radiators and was wondering:

a) if the boiler has a maximum output that I should not exceed.

b) if I should consider replacing the 8mm microbore copper with some plastic insulated piping while I'm doing the upgrade.

c) is there a 'best option' (read: cheaper) for buying new rads, assuming I don't want to just go to B&Q for their ugly offerings.

 

[Bahco]

I definitely would get shot of all the 8 mm pipe and have double panel convector rads.

See if these can do you a good deal on rads only.

 

[buraddo]

So would I just cut the 22mm at the manifold and add the plastic from there, or am I better off going closer to the boiler (the existing manifold is about 10M from the boiler)?

Also, can I go from the plastic back to copper where it comes out of the floor, for appearances, or should I just stick with the plastic right to the rads?

 

[newbuildinstaller]

You need a min of 1m of copper from your boiler but for ease I would just replace your manifold as you suggested. and yes I often step up to 15mm copper (looks 100 time better)

 

[ChrisR]

Your boiiler is more than 3 times the output you'd need, so should manage!

10m is ok

Microbore at 8mm is a pain, quite often.
10mm plastic much better. I'd use a compression elbow then go up to the rad in 10 or 15mm copper.

Biggest thing to be careful of is insulation of the skinny pipe. It's heatloss is astronomical under a ground floor, you need very thick insulation indeed.
If it's any length I'd use 15mm plastic. You need less insulation so it works out cheaper. 10mm insulation is hard to get.

 

[buraddo]

Thanks for the tips. The under sized rads are only offset by the 8mm microbore with NO insulation. My flat is always cold. I'll upgrade to the 15mm plastic and get the thicker insulation. I'm looking forward to a much more comfortable winter.

 

[iep]

My house was fitted with a perfectly powerful boiler but, just like you, small radiators and a badly installed 8mm microbore system. Some microbore runs were up to 7m long. Upshot, bl**dy freezing all winter.

To sort this I went for a full set of new rads (I simply went for the largest I could fit into the available spaces and used doubles wherever possible. You can't go too big with rads. In my case, I have been able to reduce the thermostat on the boiler so it now runs the whole system at a lower temp which (as it is a condenser) makes it more efficiant more of the time.

Try http://www.buildnet.co.uk/ for your rads. Really cheap, really quick delivery and really good quality rads.

I also ripped out all the microbore and took the system right back to the 22mm flow/return pipes from the boiler (left about 3m of copper). My house is long and narrow so I then ran a 22mm flow/return pair of pipes the whole lengtjh of the house and just Tee'd off in 15mm for each rad. Fully insulated all the 15mm runs but unfortunately it wasn't possible to insulate the 22mm main bar but it has such high flow, I'm hoping it won't be too much of an issue.

The effect is awesome. Heats up quick, totally silent and was a piece of **** to balance. Best £660 I ever spent.

Combined with replacing the blocked gas main to my boiler, I can now properly heat my home. Winner!

iep

 

[mysteryman]

Microbore, just like anything else, is OK if it is installed properly!