I am in the process of getting quotes to update my heating system. At present I have an Ideal mexico2 boiler heating 13 rads. & 2 hot water cylinders on a vented system. 
I am proposing to change the boiler, hot water cylinders & all the cold water header tanks.
Each of the plumbers I have contacted seem to favour different condensing boilers ie Ideal, Worcester & Valiant.
I have an open mind, but which is the best? or are they all on a par with each other! I understand that Valiant use a stainless steel heat exchanger so could this be better as I live in a very hard water area.
I am also looking at the pros & Cons of pressure Vs existing vent system on my 35 year old system!
Any advice, comments or experiences on boiler types would be appreciated, as would comments on pressure/vented systems
I am proposing to change the boiler, hot water cylinders & all the cold water header tanks.
Each of the plumbers I have contacted seem to favour different condensing boilers ie Ideal, Worcester & Valiant.
I have an open mind, but which is the best? or are they all on a par with each other! I understand that Valiant use a stainless steel heat exchanger so could this be better as I live in a very hard water area.
I am also looking at the pros & Cons of pressure Vs existing vent system on my 35 year old system!
Any advice, comments or experiences on boiler types would be appreciated, as would comments on pressure/vented systems