The idea of two tanks and a storage cylinder may initially put people off the open vent boiler. But the fact it can supply a number of outlets at once is a major advantage.
So firstly, there are two water tanks in the loft. One takes water from the mains supply to feed the cylinder. When the water’s been heated, it can be supplied to any tap in the house.
The other tank is for feed and expansion. It carries the right level of water required for your boiler, and allows for expansion when the water’s heated.
A downfall with the open vent boiler is that if water starts to run cold, it could take a while to heat back up. However, when fully operational, water can be drawn to any room.
People commonly switch from traditional open vents to a sealed system. It’s a cheap switchover and takes away one of the loft’s tanks.
Is the open vent boiler right for me?
Open vent boilers are pretty common in the UK and switching to the sealed system is cheap and gives you more space.
They both share the same properties and can supply multiple taps with hot water, but there is always the fear of it running cold. This means you’ll have to wait for the water to reheat.
However, the open vent has a lower water pressure and as there’s a storage system, only one outlet will have drinkable water.