Economy 7

[Bodd]

Hello all.

I'm a plumber / gas fitter. I fitted an 117 litre vented cylinder with side entry economy 7 and booster immersion heaters...

She's not even getting a full hot bath...

How can I test if the economy 7 is working or not? Or could it be an under performing element or state ?

Bod

 

[chivers67]

A clamp meter (on the Live) though it would need to be checked when economy seven kicks in it it's current set up. It could be supplied with a temporary supply to check it day time to make sure the element is drawing current.

 

[Bodd]

She is getting some hot water. So it must be working in some way

 

[JohnD]

If you take a look at the electricity meter's off-peak reading, the lower element should be using about 6kW per night to fully heat the cylinder. You may need the homeowner to check it last thing before bed, and early the next morning. This will not help if there are storage heaters or other night-time loads turned on.

How near the bottom of the cylinder is the lower (off-peak) immersion heater?

A bath contains round about 100litres of water, and as the element does not reach the bottom, there will always be less HW delivered than the nominal capacity of the cylinder. If HW is being used between the end of the off-peak time, and the time the bath is run, this will reduce the amount of HW available. I've found immersion heaters disappointing for a bath unless the cylinder is oversized.

Do you know the temperature setting of the thermostat?

If the homeowner is using the upper (peak-rate) element, this would give a small amount of HW even if the lower element was not working.

The electrical element is very unlikely to fail with poor performance, though the thermostat might be inaccurate (unlikely on a new one).

Can you photograph the meter and timer for us (timer might be a separate box or might be integral to meter) and the consumer unit(s) and the cables and any other devices around or between them.

 

[ban-all-sheds]

If you take a look at the electricity meter's off-peak reading, the lower element should be using about 6kWh per night to fully heat the cylinder.

 

[Bodd]

I've found immersion heaters disappointing for a bath unless the cylinder is oversized.

Thanks John

This is what I thought. I Under sized the cylinder... It an old money 36 x 18.

But these things are purpose made for the job. The bottom outlet is about 200mm up from base.

It's only a 1 bed flat single woman

 

[Taylortwocities]

Your first job will be to determine if electricity is getting to the immersion element when the E7 comes on.

This may mean a bit of late night on site work. Or you could put a test lamp on the supply terminals and ask the customer to get up a silly o'clock to see if the light is on...

 

[Bodd]

Your first job will be to determine if electricity is getting to the immersion element when the E7 comes on.

This may mean a bit of late night on site work. Or you could put a test lamp on the supply terminals and ask the customer to get up a silly o'clock to see if the light is on...

Yes This could be the case.

 

[JohnD]

Or you could put a test lamp on the supply terminals and ask the customer to get up a silly o'clock to see if the light is on...

A local 20A switch with neon (LED) indicator would be easier, and perhaps safer.

You can often hear when an immersion is heating, if you have good ears.

 

[SUNRAY]

I have an old electric clock (and more recently some hours run meters) which is useful for monitoring these things. Connect to the element, after t'stat, to measure how long it's heating for. Or before the t'stat to measure the length of time it's enabled for.

 

[Bodd]

Thank you all..... I just turned the stat to max. It Hardley moved but she's more than happy now.

 

[AndyPRK]

If the bottom immersion isn't working, this results in not enough water for a bath

 

[Bodd]

If the bottom immersion isn't working, this results in not enough water for a bath

It the bottom that's on the economy 7.the one that is middle is the booster..
She tells me now has a good bath and enough to wash up after.