Pepys Street RTM Company Limited

Hot Water Tanks in Flats

The majority of flats at 1 Pepys Street are fitted with a Heatrae Sadia Megaflo sealed water tank which contains two electric immersion heaters to heat the water. Firstly, you normally only need one of the immersion heaters switched on to heat the water sufficiently for general use. Having two on provides hot water which tends to be far too hot for general use so is a waste of electricity and could cause a hazard from scolding hot water.

Secondly, the tanks need a simple maintenance function undertaken on them on an annual basis. Because the tank is sealed, it contains an air pocket above the water. As time goes by this air pocket reduces in size because it is absorbed by the water. To avoid the tank from exploding, a pressure relief valve is fitted to the tank. If the pressure exceeds the safety level then the tank blows the hot water out through a copper waste pipe via an open cup which is fitted within the copper pipe work leading from the tank.

If water is dripping or flowing into this open cup then there is a problem with the tank and immediate action is necessary. The simple maintenance operation to reform the air pocket is detailed on a label on the side of the tank. However, it has been found that some of these labels are not readable or is not there so the procedure is as follows: (Click here for a printable version of the following procedure)

1. Turn off the cold water supply to the Megaflo tank.
2. Open the nearest hot tap.
3. Hold open the Temperature/Pressure Relief valve which is situated on the side of the tank near the instruction label until the gurgling noise stops and water stops running from the hot tap and the valve.
4. Close the Temperature/Pressure Relief valve and open the cold water supply to the Megaflo. When water flows from the hot water tap, close the tap. The air pocket has now been reformed.

If water continues to drip or flow through the overflow cup then the Megaflo requires professional attention. Switch off immersion heater but do NOT turn off the water supply. Contact a competent installer for advice.

Further advice can be obtained from the Megaflo Advice Line on 0870 1600125.

If you own a two bedroom flat you may find you have a different make of tank but the principle is the same as above.

If you are unsure about undertaking this task yourself, you should employ a qualified plumber. See here for help.