Replacing hot-water tank

Discussion in 'Plumbers' Talk' started by RAK1981, Jul 22, 2020.

  1. RAK1981

    RAK1981 New Member


    The house has this hot water tank, it's about 15 years old. It's always given us problems, the last one being a tidy sum of money spent on replacing a failed PCB about 2 years ago.


    I had an engineer over for a boiler service today, he had a look at the heating system in general and saw that the hot water tank was badly rusted at the back and leaking, and that it looked like it had been that way for quite some time. There was water damage on the cieling below as well, unfortunately hidden because it was the cieling inside a cupboard.

    WhatsApp Image 2020-07-22 at 19.20.25.jpeg WhatsApp Image 2020-07-22 at 19.19.51.jpeg
    He said he can't touch it because it's too badly corroded and might just fall apart if he did. He recommended that I replace it with an "unvented Megaflow hot water tank". He will provide me with a quote tomorrow.

    1. Does this all sound about right? This is the first time I have had this particular engineer over.

    2. Does this need a gas engineer or plumber?

    3. This might be ignorant of me but I've heard unvented tanks are dangerous? Could I replace this with a vented one at all?

    Thanks in advance!
  2. nigel willson

    nigel willson Screwfix Select

    Plumber with an unvented ticket is required get 3 quotes before you decide
    RAK1981 likes this.
  3. RAK1981

    RAK1981 New Member

    I got two estimates for supply, installation and disposal of old tank. They are both email estimates based on photos and information on what the system is. They said they need to have a look before giving a firm quote.

    They both recommended 200L Gledhill Unvented cylinders and said the total cost would be in the range of £1,110 - £1,400 all included.

    Does that sound reasonable?

    Also, the current tank is vented (at least I think it is because of the tank!) and has no problems supplying the water needed at the pressure required. Any thoughts on whether a vented or unvented system is better as a replacement - from the point of view of reliability and easiness to maintain?

    Last edited: Jul 23, 2020
  4. The Boiler Mate is a thermal store that does your heating as well as mains pressure hot water (not familiar with it myself so Googled it). So you can't simply replace it with an unvented without re-configuring the heating circuit and controls. Do your quotes consider this?
  5. The Teach

    The Teach Screwfix Select

    The central heating part (radiators) are on a vented system.

    Hot & cold water is at mains water pressure from that Boilermate2000. An unvented cylinder is required to give similar hot&cold tap water performance.The unvented cylinder will need annual check/service,your G3 installer will take that on or offer advice.

    converting from a thermal store like your boilermate2000 changes the characteristics of how the system works but most customers dont even know the system is working differently.

    Changing leaking or clogged up thermal stores to unvented cylinder is a common job,depending on your location £1,400 fully inclusive sounds about right.

    Straight forward job !
    RAK1981 likes this.

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