Immersion Heater - 2 immersions - help

[Amelia123]

Hello,

My hot water unvented cylinder has two heaters - one at the top called Immersion 1 and one at the bottom called Immersion 2. There are two switches which are turned on.

The two heaters also have a timer. They are both on but the timer for immersion 1 doesn't display anything (it's blank).

Please can anyone let me know what the difference is between immersion 1 and 2?

 

[CBW]

They’ll both heat up the cylinder, but if the top one fails, then you’ll get less hot water. It might Also be setup that you only need to heat the bottom one periodically.

 

[oldbuffer]

1. Immersion 1 is placed to heat the water in the top third (approx.) of the cylinder.
2. Immersion 2 is placed to heat all the water in the cylinder.
3. If you have a reduced rate tariff (e.g. Economy 7), it is normal to wire the lower heater into this. Thus the whole cylinder is heated overnight (Economy 7 usually runs 11 pm to 5 am or thereabouts) giving enough hot water for most users for the whole day.
4. The upper immersion is usually connected to normal (even more expensive) electricity, and this immersion should only be turned on for a boost if you run out of hot water.
5. The timer will normally offer a boost function. There are various different ways of implementing time control, so a picture(s) of the timer (and generally set up) might help a more precise answer.

 

[Harry Bloomfield]

The upper one is designed to heat a small amount of water, the lower one is designed to heat the whole cylinder of water.

Sometimes the lower one will work on an overnight cheaper tariff. If then you need more water during the day, you would switch on the upper one.

 

[Amelia123]

Thank you, that's very helpful.

Below is the situation with the two timers. Immersion 2 at the top is showing a green light and is displaying 'off' all the time unless I boost it. Unfortunately even after boosting it or trying to turn it on continuously there is not hot water.

Immersion 1 (at the bottom) is showing a green light but there is no display - is this normal?

I was thinking of resetting the two timers at a last resort.

My plumber is too busy to help me and said that the problem is most likely due to a wrong setting of the timer.

As a background, my tenants left two weeks ago and had turned off the switch to immersion 1 so I turned it back on.

Many thanks
Elodie

 

[Harry Bloomfield]

Immersion 1 (at the bottom) is showing a green light but there is no display - is this normal?

That would seem to suggest it has power to it. Normally the display are constantly on, but some LCD displays fail/ dim/ go blank over time. The only fix is a new unit.

 

[Dereekoo]

Instead of all this guess work has your timers got any id names on it and/or what is the make of the cylinder

 

[RandomGrinch]

Instead of all this guess work has your timers got any id names on it and/or what is the make of the cylinder

From the attached photo, it's a Timeguard 7 day immersion timer:

24 Hour/7 Day GP/Immersion Heater Timeswitch - Electronic | Timeguard (NTT03)

 

[Amelia123]

That's right. It is the Timeguard 7 day and the cylinder is Heatrae Sadia.

 

[Dereekoo]

Visit here for instructions of how to set the timers.

https://www.timeguard.com/media/2565/NTT03_NTT04_Instructs_120x60_issue3.pdf

As an aside despite what has been said earlier I assume each element is wired into a normal supply layout and can therefore be timed to come on at standard or economy & time periods and has such you can best decide what heating arrangement suits your needs. If you need lots of water heating the the bottom element in E7 periods is the way forward but if you just need a small amount in the morning then using the top element on E7 may be adequate. For a top up during the day the top element would be used. It all depends on your hot water usage/requirements

 

[Madrab]

As it's unvented I'd get someone in that is qualified to work on direct unvented and get them to check (make sure your plumber is if it's them). If you put the top one on boost and the power light is on and the green light comes on but it doesn't heat the water then that suggests that the top element may have tripped/blown.

All in all it needs looked at by someone who is qualified in unvented cylinders. Do you get it serviced once a year?