Megaflow always on question

[OlliH]

Hi,

We just moved into a 3 story house, with a megaflow system. Water is heated by a gas boiler.

The megaflow seems to be on pretty much all day , even outside of any timed heating or hot water programs - I can hear a humming sound when I open the door to the cupboard.

Is this normal ? I did notice that sometimes in the afternoon when the programs are not on, if I do a quick boost of the central heating, the gas boiler fires up. If I then switch the central heating program to off again, the megaflow stops and is completely silent.

Is something not working correctly, or I am worrying about nothing ?

thanks in advance

P.S No issues with water pressure, or water temperature

 

[SimonG]

Could be an issue with a motorised valve.

 

[Chuck]

The megaflow seems to be on pretty much all day , even outside of any timed heating or hot water programs - I can hear a humming sound when I open the door to the cupboard.

Check that the electric immersion heater has not been left switched on. It should normally be off so the water is heated only by the gas boiler, which is ca 20% of the cost of heating by electricity.

 

[OlliH]

Hi,

The switch in the cupboard where the Megaflow is, is in the off position (the red light on the switch is not on).

Using the electricity smart meter, installed by our energy provider there does not seem to be any additional usage of electricity when the Megaflow is making the noise vs when it is completely silent.

 

[Chuck]

Using the electricity smart meter, installed by our energy provider there does not seem to be any additional usage of electricity when the Megaflow is making the noise vs when it is completely silent.

If you can rule out electricity and gas as the source of energy for your 'hum' that leaves water.

Most likely candidate is a pressure reducing valve that is 'chattering' instead of closing cleanly. These are safety-critical components that must be tested/replaced by a plumber with a 'G3 unvented hot water' qualification, which will be shown on their competent persons' scheme membership card.

Other valves, such as float valves in cisterns, might also be the cause but your observation that the hum stops after the tank has been heated for a short period makes these less likely candidates.

 

[OlliH]

Thanks , sounds like I need to find a local plumber with the G3 qualification to check it out. Our current energy provider (SSE) did a boiler service as part of the heating/boiler cover we took out, but I don't think they did anything with the Megaflow other than to check it is working.