OSO hotwater boiler_Issue heating the water

Do the hands of the Grasslin timer switch show the correct time?

At the moment the picture you sent of it shows it on in these periods when timer mode is selected and the correct time is set on the hands:

1000-1200

1800-2030

2130-2230

2330-2400

(You may have changed these times in which case please send me a new photo).

Does the vertical cable from it still go to the top element?

For the timer to keep the correct time the left hand water heater switch must be left on. You can then use the three position slider switch near the hands to control the top heater, the three positions being timed mode, off and permanently on.

Nicole_ I hope you are just busy and not that you are tired of all my questions ;-)

I want to give you some questions for an electrician to answer once he/she has visited and inspected what's what - because there will need to be a visit paid for by your landlady. But just need a little more information first. We can bowl out the tank and its heaters now as the problem.

There are female electricians if you would prefer one to visit. We can also see if a trusted forum member is near by.

Hi marconi! Sorry I didn’t reply, I was just busy. Thanks again for all the info though. So to answer the questions.

Night Immersion- The orange light doesn’t illuminate. It actually goes on and off. Like it’s flashing sometimes. But, the majority of the time it’s off.

Grasslin timer- I changed the times today because my landlady asked me to do so to check if it’s going to work. I did but still it doesn't work. Just to say again though, that this timer I have it on the permanent position which means that it doesn’t matter anyway what times I put there. If a photo is still needed then let me know.

Vertical cable- I don’t know exactly where it goes to because they get mixed under that white thing and then I don’t know where it ends up.

Electrician- My landlady said she has asked the plumber to bring an electrician. But, yes if there is a trusted forum member I could consider and pass the info to the landlady.

What questions would you recommend asking the electrician?

What is your district in Liverpool so I can make some enquiries about forum electricians in your area?

The items I have highlighted in bold are what you need to address with the electrician.

The flashing orange light is not right. Please leave that switch turned off for now. It needs an electrician to investigate.

If the hands of the Grasslin timer are not moving and keeping correct time then it is duff and requires replacement. But as you say in constant on mode that provides power to the immersion top heater controlled by the left hand switch. But you only heat the volume of water above the heater as heat rises. To keep the correct time it needs the left hand switch to be left on - is this what you have done?

Your installation is lacking a way of turning the bottom element on and off to match off peak electricity rates. An electrician will have to provide another time switch for the bottom element. See my recommendation at the end.

You are on the wrong type of tariff for electric water and space heating because you have no periods of off peak electricity. Have a chat with a neighbour who has electric water and space heating and find out what scheme of off peak tariff they use, the two most common be Economy 7 which is night time only and Economy 10 which is night time and some day time periods also. Study this link and then think about which is best for you:

What is Economy 10? A complete guide to Economy 10 meters and tariffs - https://www.uswitch.com/gas-electricity/guides/economy-10/#:~:text=How%20Is%20Economy%2010%20different,hours%2C%20usually%20in%20the%20afternoon.

The good thing about E7 and E10 is that they apply to all the flat's electricity consumption during the periods of lower rate which means one can with an eye on the clock or using timer functionality in the appliance run washer, dryer, dishwater or cooker and benefit from cheaper electricity. If your meter is not capable of dual rate then it will have to be swapped for one that is by your electricity supplier.

I want to see if your Landis and Gyr E470 electricity meter is capable of dual rate. Please would you follow what this short video tutorial shows and tell me what the display toggles between:


For Megan, who had a problem with her electric heating control we fitted this single timer which can control both the top and bottom elements and arrives preset with the common economy rate tariffs like E7 and E10 so all the electrician has to do is select the one you have arranged with your electricity supplier. Nice and simple to use. A rocker switch to select the bottom element Always off/timed and a button to press to increment a boost period time duration for the top element in steps of 1/2, 1 and 2 hours which can be cancelled after selection should one wish. Two lights indicate which element is on. See:

Sangamo Powersaver Dual Flexi Timer and Boost | Sangamo (PSDF2) - https://www.tlc-direct.co.uk/Products/SGPSDF2.html

So, the electrician came and he said everything looks fine. He took the cover out of the switches to check the cables and he said there is nothing wrong. He set the times and raised the temperature on the thermostat. Will keep an eye to see if the water gets heated etc now.

For the flashing light, he said it’s just the neon that is not working.

About the grasslin- If I have it on the constant on mode, then does it matter if the time is wrong when I switch it on?

I need to look at the tariff.

I need to dedicate an evening reading through all this information you have provided and understand things better. All these are so new to me and I’m trying to understand.

About the grasslin- If I have it on the constant on mode, then does it matter if the time is wrong when I switch it on? No. Top element will be completely controlled by Water Heater switch.

For the flashing light, he said it’s just the neon that is not working. It is safe to use then. Would have been nice to replace with a new switch with working neon but you can live with it.

One query which you have not reported on is what to do about time control for the lower element. This can be sorted out when you have decided on whether and which off peak tariff to use and from which supplier.

Just be careful drawing off hot water since the thermostat temperatures have been increased - it could be very hot now.

Please keep me posted on what you decide to do next.

I feel compelled to comment on the matter of the dual rate tariff.
There is a down side in that peak rate electricity is more expensive when you move to a dual rate tariff, so you need to be using a good proportion of power at night (between 45% and 50% is the break point) otherwise there is no saving, in fact the opposite, it is more costly!
If there is storage heating (in use) powered from off-peak, then a dual rate may be more economical, at least for the winter.
If heating is powered partly or completely by normal rate (eg convector or panel heaters), and the 45-50% demand for off-peak is not met, the overall cost will be greater on a dual rate (eg E7).'

I moved from E7 to single rate tariff because heating our 220 litre Cylinder is cheaper that way. We don't have storage heating.

To work out the exact position, you need the rate costs from your supplier, and an idea of the ratio of daytime consumption (or load) to night time consumption/load.

Well at the end of the day you dont need hot water as its getting warmer now.

driverJohn said:

Well at the end of the day you dont need hot water as its getting warmer now.

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Was -2 degrees when I got up this morning. Definitely needed hot water!

Avo Mk8 said:

I feel compelled to comment on the matter of the dual rate tariff.
There is a down side in that peak rate electricity is more expensive when you move to a dual rate tariff, so you need to be using a good proportion of power at night (between 45% and 50% is the break point) otherwise there is no saving, in fact the opposite, it is more costly!

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While this is generally the case, I've seen E7 tariffs with peak rate maybe only 0.5 pence more expensive than 24 hour tariff since prices have shot up. Always worth looking at options and keeping an eye on suppliers.

nicebutdim said:

While this is generally the case, I've seen E7 tariffs with peak rate maybe only 0.5 pence more expensive than 24 hour tariff since prices have shot up. Always worth looking at options and keeping an eye on suppliers.

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I may be gullible taking this at face value: https://www.moneysavingexpert.com/utilities/economy-7/

The average figures I've looked at have a notable disparity between on and off peak rates - eg

Figures do vary quite a bit, and I guess it all depends what you can find /negotiate!

Avo Mk8 said:

I may be gullible taking this at face value: https://www.moneysavingexpert.com/utilities/economy-7/

The average figures I've looked at have a notable disparity between on and off peak rates - eg
View attachment 107313

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Just checked Power NI and the difference has widened slightly since last year, but the tariff I'd looked at for a customer with keypad is now 33.73 pence/kWh peak, against 29.42 pence on a 24hr rate. Not insignificant, but considerably less in percentage terms than prior to price hikes.

Last year Scottish Power actually reduced the off peak price of my E7 supply, so that they could increase the day rate by a greater amount and still keep within the Government's limits.

I called British Gas again the other day and asked them if I can have the E7 rate. They said an engineer would have to come to install this but there was nothing available in the next month.

Reading all the comments above that if I get E7 then the day rate will increase, I have started considering whether I would like to have the dual rate.

P.S: I don't know if that's a miracle, but since the electrician came two weeks ago somehow I have enough hot water again. I don't know whether the fact that he opened the lids of the two switches and looked ad the cables made a difference. I have no idea! I still have a fear though that all of a sudden I things might stop working again lol. This whole thing was a bad experience because both the plumber and electrician didn't really know what was wrong.

Once you have had an E7 meter installed, and if you find that your electricity costs have increased, you do not have to have the meter changed again to go back to a 24 hour tariff. There might well be a minimum contract term for your E7 tariff or exit fees to pay before it expires, but your supplier should be able to offer an E7 tariff where day and night rates are exactly the same, and identical to the 24 hour tariff.
I recently did this with a couple of Eon accounts, and although they initially said that such a tariff doesn't exist, and I would need to have 'smart' meters fitted, I knew full well that they did, and after 13 emails, and 13 replies, I was transferred to the 24 hour tariff equivalent.