Heater, at last.......

[oilyrag]

Having read as many of the topics on poor heating as I could find, bled/flushed the radiator/heater more times than I care to admit over the past 3 years, the heater was still pathetic. Just a tiny bit of warmth after parking up for a while, which would rapidly disappear. It has snowed here over the past two days and it was either sort the heater or get another car. The engine came up to temperature quite quickly (new stat) but little hot water appeared to be circulating through the heater pipes. 
In yet another attempt to bleed at the heater connector I attached a tube to the bleed nipple and put it into a bottle, half filled with water/anti-freeze. Started up and all the water got sucked out of the bottle. Not what I'd expected. 
The it dawned (after 3 years..... ) - the bleed valve is on the return side of the heater matrix and the water pump sucks at this point. The water disappeared from the bottle as the matrix was clogged up and wouldn't allow much water through, creating the 'vacuum' in the return pipe. Even less water would pass through when the thermostat opened - as the heater system was then by-passed completely.
Before coming to Ireland I lived in Norfolk, where the car had spent its whole life. Very hard water there - maybe the matrix had scale in it? 
So, taking the view that I'd just bypass the heater if all went wrong and be no worse off, I took off the connector and added some kettle de-scaler to the matrix pipes via both tubes. Left 5 minutes, flushed with a hose and then repeated. Left flushing for 10 minutes, both directions. No water on floor inside the car, so the acid hadn't eaten the matrix (I hope!).
Started up, engine up to temp quickly and immediate sauna-like (well, relatively) heater. It's going to beat scraping the ice from inside the screen!

[Lighty]

Great result, it’s not that hard to change the matrix if you have a day spare, then it really will scorch you.
Great result that it hasn’t leaked.