We have this boiler and it been working fine for a year but a month ago it started to act weird, the problem is that when we turn on the heating it doesn't work the first time we have to turn the rotary switch one position more and then leave it again on the "winter porition"
Why is this happening? any ideas or anything we can do?
Suspect the system is clogged up, how to check? ..well if bottom of rads is cold and top warm them sludge in system.
This means a complete drain down of all water in system make sure turn power to boiler off first. if water runs dirty i.e. a brown/ black colour then you have sludge.
You will need to put cleanser in system go to plumbers merchants approx £10= £18 for 1 litre.
Put it into system via towel rad if you have one ,if central heating fill tank is in loft then pour cleanser in there ( if you have this tank when draining down you must turn the water off so this tank does not fill as you drain down) fill system with water bleed all rads of air starting downstairs first and finishing with the highest rad, let system run as normal for 4 weeks and then drain down if water still significiantly dirty then repeat process once again.
On next drain down refill system with clean water then run for 1 hour drain down then refill system but you must put inhibitor in the system , i think Screwfix sell 5 litres for about £24 just put all 5 litres in bleed system as before.
Bit of a pain i know but cheaper than a call out bill !