Twin Immersion Tank

Mbw299

Hi

i have a twin Immersion tank to provide hot water with two heating elements - both Backersafe Type BS311C. These are connected to the wall where a separate switch for each is attached. Recently I lost hot water and called someone round. It was found that the switch for the bottom heating element was off and the heating element required resetting. This returned the hot water but the engineer's company is refusing to tell me why this worked.

I have two questions:
1) could I receive hot water with just the top heating element turned on?
2) why would an element require resetting?

thanks for any help,
Marc

Richie-from-the-Boro

Mbw299 wrote: »

Hi

i have a twin Immersion tank to provide hot water with two heating elements - both Backersafe Type BS311C. These are connected to the wall where a separate switch for each is attached. Recently I lost hot water and called someone round. It was found that the switch for the bottom heating element was off and the heating element required resetting. This returned the hot water but the engineer's company is refusing to tell me why this worked.

I have two questions:
1) could I receive hot water with just the top heating element turned on?
2) why would an element require resetting?

thanks for any help,
Marc

Top only will give very little hot water perhaps 10/15% of volume. No idea why he would not tell you other than the fact that pushing the reset keeps him in work.

CashStrapped

OK.... it is very simple actually.

I assume you are in an all electric property. There are usually two types of all electric property.

1) Those that just have a standard meter and one rate of electricity
2) Those that have an e7 (economy 7) meter and two rates of electricity.

Those on an e7 meter and e7 tariff (two rate) have a more expensive rate of electricity during the day and a very cheap rate of electricity at night.

The idea behind this is that an E7 property has storage heaters which charge and store heat at night. In addition the hot water storage tank will heat the water during the night too.

This ensures the vast majority of your electricity use is done on the cheapest rate possible. Most E7 properties aim for 65% on the night rate. The higher the night percentage, the cheaper the bill.

The two immersions in your hot water tank are part of the E7 set-up. The bottom element heats the whole tank (at night) and should last the whole of the next day (if well insulated).

The top element is a "boost" and only heats a small part of the tank. However as this would be used during the day, it will the charged at the expensive day rate.

However..................

Some landlords rip out the storage heaters (because they are under the false impression they are rubbish) but leave the E7 tank as is. This means that either immersion element will now use the expensive day rate. The top one just heats less water.

So if you have standard panel heaters, and a single rate tariff, you unfortunately can no longer benefit from an E7 tariff.

---

The heater element in the immersion has a thermal cut out - this can cut off the immersion if, for some reason, the water gets too hot. It prevents the element from over heating. There is a temperature dial in the immersion (do not touch unless the electrics are all off) which you can use to adjust the temperature the immersion heats the water to. The engineer probably lowered the temperature a bit, then reset it.

If it fails again, this may be a sign that the element needs replacing.

coffeehound

CashStrapped wrote: »

The heater element in the immersion has a thermal cut out - this can cut off the immersion if, for some reason, the water gets too hot. It prevents the element from over heating. There is a temperature dial in the immersion (do not touch unless the electrics are all off) which you can use to adjust the temperature the immersion heats the water to. The engineer probably lowered the temperature a bit, then reset it.

If it fails again, this may be a sign that the element needs replacing.

I suppose one distinction to make here is that the problem could be just the heating element's thermostat that is faulty. In that case just the element thermostat can be replaced, which is good news because it doesn't need the system to be drained down. E.g.



http://www.jewson.co.uk/electricals-plumbing-heating/heating/cylinder-accessories/immersion-heaters/products/HB13201B/backer-1122-bmst11s-20-amp-re-settable-thermostat/

.