Vaillant combi CH draining

[DIYspanner]

The rad by the front door has a drain valve but how is the system entirely drained when there are pipe runs under the floor which are lower then the drain valve?

I was planning to get this kit from SF to drain, fill with cleaner, drain again then refill with inhibitor.

 

[CBW]

A drain valve on a radiator will only drain to that point, not anything below it.

 

[DIYspanner]

A drain valve on a radiator will only drain to that point, not anything below it.

Exactly my point.

Since the drain valve on the rad pipe is the lowest drain point, any crap in the lowest pipe work cannot effectively be removed. There's also the fact that a small amount of any cleaner used to flush the system will be left in the lowest pipe work when its drained.

All the rad pipes are push fit, the lower floor being 10mm, the upper floor being 15mm.

 

[oldbuffer]

1. A power flusher would help by continually diluting the c**p in the lower runs. A mains flush would have much the same effect.
2. If you can get under the floor at the lowest point, cut in a tee and a drain off valve.
3. Use a wet and dry vacuum to clear the lower pipes.