Topping-up Expansion Tank - How Often is Too Often?

[Johntheo5]

There are numerous posts around complaining about the frequent top ups required for these type of HW cylinders, also the Megaflo has a air baffle which can break up and cause problems with clogging up mixing valves etc. OSO make one with no baffle but requires a almost full drain down to recharge the air bubble vs ~ a max of 25% drain down to the bottom of the dip tube on the Megaflo and its likes, I've always reckoned that you could get up to 5 times the Megaflo recharging intervals if it was also fully drained down but would require a bit of planning to ensure most of the HW is used up before doing so.

I have seen UVCs abroad that have neither a air bubble or a EV, they just use the expansion relief valve (well named?) to control the max pressure on reheat, of course wastes a few litres of HW at each reheat, they also though have the cylinder T&P relief valve.

 

[endaxi]

There are numerous posts around complaining about the frequent top ups required for these type of HW cylinders, also the Megaflo has a air baffle which can break up and cause problems with clogging up mixing valves etc. OSO make one with no baffle but requires a almost full drain down to recharge the air bubble vs ~ a max of 25% drain down to the bottom of the dip tube on the Megaflo and its likes, I've always reckoned that you could get up to 5 times the Megaflo recharging intervals if it was also fully drained down but would require a bit of planning to ensure most of the HW is used up before doing so.

I have seen UVCs abroad that have neither a air bubble or a EV, they just use the expansion relief valve (well named?) to control the max pressure on reheat, of course wastes a few litres of HW at each reheat, they also though have the cylinder T&P relief valve.

Well, I did the regeneration today in about 20 minutes although struggling with the stopcock took up several minutes of that. I really ought to do it more often as it's no real bother but somehow I'm always reluctant.

I don't have any symptoms of a disintegrating baffle but I do believe any advantage of having it is outweighed by the potential problems it can cause.