Unvented Cylinder (direct or indirect DHW)

pete3226

Hi,

I am new to this, so be easy on me. I am buying a Victorian home with no central heating. Hot water is currently supplied by an immersion cylinder. I am getting rid of the old systme and I am considering installing a Megaflo type cylinder and boiler to give me good water pressure. A friend of mine told me that Megaflo uses a heating element to heat the water directly, but I want an indirect system whereby I get mains pressure, but the cylinder is heated by water from the boiler indirectly (because an electric immersion is more expensive).

Is this possible? What are the pros and cons of direct over indirect other than costs? thanks you!

bambibashercol

Even a indirect cylinder has a immersion as back up should your boiler fail. Your plumber will advise you and make sure he has a g3 certification as a un vented cylinder, if installed wrong is a real hazard. The plumber will also need to make sure you have a good enough pressure and flow on the mains as if not enough pressure and flow you will be wasting your time and money.

Lgas

Hi, a megaflow is an indirect unvented cylinder, it can have an immersion as a backup. Mine is absolutely brilliant, I have the water on for an hour every other day or as needed as i'm amazed at how long it keeps the water hot. The water pressure is great, if your system is up to pressure i'd highly recommend one. Just do as the previous poster advised and ensure it is installed correctly, the safety devices are extremely important as well as pipe layout etc.

owned_by_2_Siamese

Maybe I'm unlucky but have had these systems in my last two houses (although latter was Telford Tornado - same pronciple) Both have been expensive nightmares. The problem is always the expansion vessel (large cylinder either on top of hot water cylinder or seperate) they have a rubber membrane to take the expansion of the heated hot water - which would otherwise have no where to go. They last about a year, and I dont mean needing topping up they just fail - resulting in cascading water from overflow if you are lucky or as happened last time water overflowing out of the tank all over the house. This happens as the pressure ruptures either the coil or the tank when it fails (even if you have a pressure release valve) Most systems/tanks are guarnteed for many years - the expansion vessel is usually only guaranteed for 2 years - that tells you something.
I agree mains pressure hot water is great - but there is a lot to be said for the time tested old fashioned expansion tank set up.
Like I said maybe I'm just unlucky!