Blocked Microbore pipes

I have a 1/4 inch microbore system with 9 radiators running off the upstairs manifold and 9 off the downstairs (typically 2 rads per room, not lots of rooms). Several are reluctant to warm up, staying lukewarm or totally cold.

Disconnecting a rad shows the problem is in the pipes, not a blockage in the rad itself. Only a trickle (at most) is coming through.

I'm scared to put in a chemical cleaner. The downstairs pipes are set in the solid concrete floor so can never be drained fully, and I don't want them to spring a leak.

Any suggestions or advice? Does it matter if the cleaner doesn't get completely flushed away?

Alan

A proper powerflush will eliminate all of the chemical that is used during the flushing of the system, as it si pumped around the system.

you could still get rid of all the chemical with a manual flush by cold flushing the system afterwards.

Or you can save youself a wedge and do a manual mains flush yourself. See the FAQ topic or the Wiki for details.

With microbore its unlikely that any joints have been fitted within the concrete so you can do chemical treatment fairly safely.

The MO to use is to first turn OFF all rads working well!

Introduce the chemical and run the system for a while until hopefully the rads improve. Then open the remainder and clean them.

Tony

I had no end of trouble trying to get a rad working on such a system, powerflushed the system that rad in garden, that branch on it's own. Still no go, repeated all the above.

Turned out to to be the valve.

If you have those awful valves that take both microbore pipes in at one end, and you still have a problem, change to one at each end.