Plumbing in new radiators

[Jever]

Hi,

My dad has a Grant 26e external combination oil fired boiler with the water pressure provided directly by the mains water and he would like to upgrade a couple of his radiators to match the others, which (I assume) ultimately means draining down the system and changing the pipework (some of which is in the screed beneath the floorline).

I would therefore appreciate some views from professional plumbers on the following questions:

• Assuming we need to drain the system down to make the changes, is it normal with the heating system I mentioned to be able to switch of the mains supply to the heating circuit but leave the supplies to the taps still on? I have an old oil fired boiler with a live mains feed and can do this in my home, but I'm not sure my dad's system allows for this.
• Is it usual to have a drain off cock with such a system? We can't seem to locate it. What would a professional plumber do when they want to change the pipework on a system like this? I assume you drain down and do soldered joints, correct?
• If I can't get all of the water out of the system, I was thinking about making some of the joints in either brass compression or plastic push-fit fittings. Is it safe to use these sorts of fittings in the screed?

Thanks in advance for any help.

Regards

Jever

 

[endecotp]

• Is it usual to have a drain off cock with such a system? We can't seem to locate it. What would a professional plumber do when they want to change the pipework on a system like this? I assume you drain down and do soldered joints, correct?

Some drain valves are very well hidden. I found mine under the floor boards - marked with an "X" - when I replaced a carpet. Of course I had replaced the radiator before replacing the carpet...

If there really isn't one you can drain from a radiator. There are tricks to get some of the remaining water out, e.g. blowing down pipes.
Don't bury compression fittings or push-fit in screed. Or use them anywhere else that's concealed.

 

[dilalio]

You can buy a self-cutting drain cock that clamps onto a pipe and makes a hole in it. Then just remove this and repair pipe when system is empty. A wet/dry Hoover is a good idea to suck all the sitting water out of the lower pipes which prevents mess and makes soldering easier on low horizontal runs.

http://www.screwfix.com/p/self-cutt...tracking url&gclid=CKzJyarfu9ACFQ4R0wod4J4PQQ

 

[Jever]

Hi,

Thanks for the ideas, I like the idea of the hoover clearing the water from the pipes, as we have a wet hoover available to us.

Is there a fitting available that gets you from 'hoover bore' to 15mm copper, or is this best 'self-created'?

Regards

Jever

 

[dilalio]

Hi,

Thanks for the ideas, I like the idea of the hoover clearing the water from the pipes, as we have a wet hoover available to us.

Is there a fitting available that gets you from 'hoover bore' to 15mm copper, or is this best 'self-created'?

Regards

Jever

I just use my hand to create a 'seal'