Time of Economy 7

valiant24

QrizB said:

Using the 5th terminal or the 2A relay instead of the Honeywell timer would be more reliable (you wouldn't neeed to know the switching times, it would happen automatically) but would require some work by an electrician.

Ah, so any competent sparks should be able to rewire this so that the Aga fires up automatically?  It wouldn't need a specialist engineer from British Gas?   Odd then that the British Gas or PEP engineers didn't wire it in that way when each fitted a new meter in 2021 then?

If so I might look into that, although I am planning to try Octopus and EDF by phone tomorrow to see if I can switch: both have a Night rate that is marginally cheaper than British Gas's (15p vs 16p/kWh), and both do I think offer a smart meter for Economy 7.

lohr500

From the photo, I concur with QrizB.

It looks like you have a two rate meter, but nothing exiting from it to energise any dedicated off peak circuits.

What model is your electric AGA?

If it is a 30 Amp version like ours, then it won't work correctly during the day if you switch it off fully outside of the off peak hours.

The reason for this is that it has a heat circulating fan which is thermostatically controlled based on the oven temperature.
As the oven temperature falls, the fan kicks in to draw air through the core (which at full temperature is around 700 deg C.) and distributes the now hot air around a cavity which surrounds the ovens and hot plate bases.
The oven temperature should be adjustable using the setting on the controller.

Without daytime power to the fan and controller, the hotplates and oven will cool down fairly quickly, making it difficult to cook.

Our 30 Amper needs around 5 1/2 hours of continuous off-peak electricity to reheat it each day.

Three things to consider if yours is regularly going into "Doing the Naughty Thing" mode. 

1. Assuming the Honeywell timer is being used to provide the low current off-peak voltage signal to the AGA, make sure the off peak time on the Honeywell timer is set for at least 6 hours to give the AGA chance to fully heat up. If it isn't then your core won't be getting hot enough overnight to provide sufficient output to last the day. Especially if you use the AGA a lot.
2. You probably know this already, but try to minimise use of the boiling and simmering plates as a lot of heat is lost when they are in use. We cook as much as possible in the ovens.
3. Get an engineer who understands electric AGA's to check the heating elements. The very early ones had a single bank of elements wired in series, so if one element failed, the whole heating circuit stopped. Later models (and early models that were modified) moved to three banks of heating elements. If one of the three banks fails, the others keep working, but struggle to get the core to full temperature within the 7 hour off-peak window. Especially if it is the middle bank which has more elements. If yours is a 30 Amp model and it isn't stone cold, then it is safe to assume it has the later three bank element set, so a failed bank could be a real possibility if it is regularly going into peak boost mode.

If you are a competent electrician, it is not difficult to check the heating elements and replace them yourself. But you should only attempt this if you are competent and know what you are doing. I have changed two sets of elements on mine over the past 29 years.

Hope this helps. Please let me know which AGA model you have as my advice above is based on the 30 Amp version. The more modern ones may work differently.

valiant24

lohr500 said:

From the photo, I concur with QrizB.

It looks like you have a two rate meter, but nothing exiting from it to energise any dedicated off peak circuits.

What model is your electric AGA?

If it is a 30 Amp version like ours, then it won't work correctly during the day if you switch it off fully outside of the off peak hours.

The reason for this is that it has a heat circulating fan which is thermostatically controlled based on the oven temperature.
As the oven temperature falls, the fan kicks in to draw air through the core (which at full temperature is around 700 deg C.) and distributes the now hot air around a cavity which surrounds the ovens and hot plate bases.
The oven temperature should be adjustable using the setting on the controller.

Without daytime power to the fan and controller, the hotplates and oven will cool down fairly quickly, making it difficult to cook.

Our 30 Amper needs around 5 1/2 hours of continuous off-peak electricity to reheat it each day.

Three things to consider if yours is regularly going into "Doing the Naughty Thing" mode. 

1. Assuming the Honeywell timer is being used to provide the low current off-peak voltage signal to the AGA, make sure the off peak time on the Honeywell timer is set for at least 6 hours to give the AGA chance to fully heat up. If it isn't then your core won't be getting hot enough overnight to provide sufficient output to last the day. Especially if you use the AGA a lot.
2. You probably know this already, but try to minimise use of the boiling and simmering plates as a lot of heat is lost when they are in use. We cook as much as possible in the ovens.
3. Get an engineer who understands electric AGA's to check the heating elements. The very early ones had a single bank of elements wired in series, so if one element failed, the whole heating circuit stopped. Later models (and early models that were modified) moved to three banks of heating elements. If one of the three banks fails, the others keep working, but struggle to get the core to full temperature within the 7 hour off-peak window. Especially if it is the middle bank which has more elements. If yours is a 30 Amp model and it isn't stone cold, then it is safe to assume it has the later three bank element set, so a failed bank could be a real possibility if it is regularly going into peak boost mode.

If you are a competent electrician, it is not difficult to check the heating elements and replace them yourself. But you should only attempt this if you are competent and know what you are doing. I have changed two sets of elements on mine over the past 29 years.

Hope this helps. Please let me know which AGA model you have as my advice above is based on the 30 Amp version. The more modern ones may work differently.

Hi.  I'm not actually sure which model I have!  Mrs V thinks it's a 30A model.  Here's a pic: https://postimg.cc/PNJ6r0Qh .

Noted that the fan will go off when we power it off for The Naughty Thing.  Perhaps should be the subject of a separate thread but what should the fan be set to from 0-6?  We both love cooking on the Aga but its principal purpose is to keep warm a kitchen which has no other source of heating.  We have separate induction hobs in the kitchen so, perfect toast apart, don't really have to use the hotplates.

The house is an 18th century one that was derelict for decades until 1990, when it was brought up to modern habitation standards.  It had the same model Aga, presumably 15yo by then, when we bought it in 2005.  In 2014 we replaced with the current model it as it seemed to be becoming unreliable.  In fact the new one has been worse for reliability than the old one ever was, and in those 8 years we've spent nearly half what it cost (£8k) on frequent repairs.  Aga the company could not care less and words can't express the contempt I have for them.  But anyway, I'm getting rantily off the point!   Which is .... it's had so many components replaced etc that there's no appetite to throw even more good money after bad.

QrizB

valiant24 said:

QrizB said:

Using the 5th terminal or the 2A relay instead of the Honeywell timer would be more reliable (you wouldn't neeed to know the switching times, it would happen automatically) but would require some work by an electrician.

Ah, so any competent sparks should be able to rewire this so that the Aga fires up automatically?  It wouldn't need a specialist engineer from British Gas?

Yes to your first, no to your second. You will need an electrician who has been authorised to remove the DNO fuse (or who has an agreement with one who has).

You might want to get a quote before committing to it, as it could involve running a second supply to your Aga with all the disruption this entails.

valiant24 said:

Odd then that the British Gas or PEP engineers didn't wire it in that way when each fitted a new meter in 2021 then?

The engineer fitting your meter isn't going to do much more than that. They're not usually going to fit equipment that wasn't there before they arrived, like a 5th terminal feed.

If so I might look into that, although I am planning to try Octopus and EDF by phone tomorrow to see if I can switch: both have a Night rate that is marginally cheaper than British Gas's (15p vs 16p/kWh), and both do I think offer a smart meter for Economy 7.

If you are going to get a smart meter fitted, try to get something installed (even if it's just an empty E7 consumer unit and tail) before the meter engineer arrives, so they can make the connection to the meter.

lohr500

OK, as far as the AGA is concerned, it looks like a 30 Amp model with a Mk 2 controller.

I think this document covers the instructions :

https://silo.tips/download/users-instructions-for-aga-electric-cooker-models-electric-c-2-oven-2-electric-e

The 0 to 6 dial is used to set the oven temperature. Best set to 4 for normal use. 
The heat circulation fan will cut in and out periodically to keep the oven temperature at the level set by the 0 - 6 dial.
The heat circulation fan will run even during the peak rate electricity window as all it is doing is dragging hot air out of the core and circulating it around the oven/hotplate jackets.

The red button controls an extractor fan fitted to the top oven. We only use the extractor fan for short periods if cooking things that generate a lot of steam or fumes. My thinking is that the more it runs, the more it will cool the oven so more hot air will be needed from the core to keep the oven at the set temperature.

The top green LED indicates that the main permanent 32 Amp feed to the AGA is switched on. 

The bottom red LED should only light up when the AGA is receiving the off-peak trigger signal from your Honeywell timer.
It doesn't indicate if the oven is actually charging or not. Just that the electricity available is on the off-peak rate.

I am not sure with your controller if that red LED blinks when charging the AGA during peak rate. Our replacement non original controller is slightly different and it does flash if peak rate charging is taking place.

I am pretty sure your Honeywell timer will be wired to the 5 amp trigger circuit on the AGA. You can prove this by switching the timer on and off manually and seeing if the red LED on the AGA lights up and goes out. The green light should remain on permanently, irrespective of the Honeywell timer settings.

Hope this helps.
  

valiant24

lohr500 said:

The bottom red LED should only light up when the AGA is receiving the off-peak trigger signal from your Honeywell timer.
It doesn't indicate if the oven is actually charging or not. Just that the electricity available is on the off-peak rate.

I am not sure with your controller if that red LED blinks when charging the AGA during peak rate. Our replacement non original controller is slightly different and it does flash if peak rate charging is taking place.

I am pretty sure your Honeywell timer will be wired to the 5 amp trigger circuit on the AGA. You can prove this by switching the timer on and off manually and seeing if the red LED on the AGA lights up and goes out. The green light should remain on permanently, irrespective of the Honeywell timer settings.

Hope this helps.
  

Thanks for everything thing, lohr.

On our model, the red light is off most of the time, like now.
It comes on solidly when the timer kicks in to "On".   The Honeywell timer also has an "override" button which, when pressed, brings the red light on solidly.  I just tried this to make sure.

When the Aga is Doing the Naughty Thing that same red light flashes, rather than is solid.

lohr500

Good, it sounds like it is all wired correctly.
And like our controller, a flashing red light is indicating that the AGA is charging during peak rate  ( In Doing the Naughty Thing mode !! ).
I am presuming the green light is on all the time as I don't think the red light would work without having the permanent feed.

So next thing to do is to check that you have the Honeywell timer set to come on for at least 6 hours during the off peak period to be sure the AGA fully charges. Better to go for 6 1/2 hours, with it staring 15 minutes after 01:48 BST.

If you don't use it much for cooking, then there shouldn't be many instances of Doing the Naughty Thing. Ours only kicks in on peak when we have used it for lots of cooking all day, like at Christmas.

If Naughty Thing is making a regular appearance after setting the timer to give 6 1/2 hours off peak signal and you aren't cooking with it a lot, then I would very much suspect a failed element bank or faulty core temperature sensor/controller fault.

To replace a single bank of elements on a DIY basis costs between £200 and £250 depending on which element bank has failed.
I was getting Naughty Thing syndrome last year on a regular basis, with a reduced hotplate temperature and sure enough it was a failed bank.

If the elements are all OK, then unfortunately it means there is probably an issue with the control module or the temperature probe  Again with DIY knowledge and a multimeter it is easy to check the thermocouple probe reading. The probe itself isn't expensive, but as I know dearly, the controller is !!!

How often does Naughty Thing appear and have you got the Honeywell timer set to give close to 7 hours of "on" time?

valiant24

lohr500 said:

So next thing to do is to check that you have the Honeywell timer set to come on for at least 6 hours during the off peak period to be sure the AGA fully charges. Better to go for 6 1/2 hours, with it staring 15 minutes after 01:48 BST.

How often does Naughty Thing appear and have you got the Honeywell timer set to give close to 7 hours of "on" time?

So after last night's investigations, the timer is now set to come on at 0050 GMT.  It can only be set in 10 minute quantums.  So it runs from 0050 to 0250, then 0300 to 0740.  Should be OK but I am absolutely relying upon Economy 7 kicking in at 0048 every night!  May set up some time-lapse photography for a few nights ....

To be honest I can't remember whether it's been Doing the Naughty Thing much since we last called Spillers (our nearest Aga engineers, an hour away) out.  It did it late last night but in fairness it had been off all summer and had only had about 9 hours' charging from cold.   I'll just have to keep an eye on it.   I wish there was some way of blocking it from taking charge outside cheap hours without turning the whole thing off.

cheers
V

lohr500

Given that the main Landis meter is controlled by an internal digital clock, I wouldn't expect it to drift a great deal. But worth checking every month or so, just to be sure. And also check the clock on the Honeywell timer as well on a similar frequency.

Personally I would set the on period from 01:00 to 07:30 to give a bit of leeway. 6 1/2 hours should be more than enough to fully charge the core after a normal day's use based on my experience.

You should definitely see what happens when the clocks switch back to GMT as well. Either or both of the timers may have automatic adjustment for BST/GMT and could get out of line with each other. Our off peak rates are based purely on GMT and don't change with the clocks. 

I suspect you are right that it may not have fully charged from a cold start yesterday. Keep an eye on it this evening and if it starts flashing red again, then perhaps there is an underlying problem as I described in my earlier reply.

dunstonh

valiant24 said:

By dint of moseying out into the pouring rain and looking at my external meter every few minutes, I determined that my Night rate kicked in this morning at 0148 (so 0048 GMT).

Can I be sure that it will be the same time every night?  It's important as I have a power-guzzling Aga.

Thanks

V

I have an 30amp AGA and I suspect that is what you have.  So, making sure the timer is right is vital.  (edit: your later picture is a 30amp).  Also the 30amp is the only economy 7 one as the 13amp wasn't E7.

I check the time on my meter against the timer on my AGA each month when I grab the meter reading.  it tends to move a few minutes each month but then it will just several hours.  Currently my Eco7 time is 08.49 to 15.49 which is great.  However, I am hoping the next jump occurs soon and I can get some evening time in there as well.

Digital meters are prone to gaining time.  Which can be beneficial but it is vital to keep checking.

 A main 32 Amp feed which is permanently live.
A second 5 amp fused feed which is the Economy 7 signal. This feed should be wired back to a separate fuse box/consumer unit which is only "live" during the Economy 7 period.

That is one method. Timers are the other method.

n our model, the red light is off most of the time, like now.
It comes on solidly when the timer kicks in to "On".   The Honeywell timer also has an "override" button which, when pressed, brings the red light on solidly.  I just tried this to make sure.

That sounds exactly like how ours is done.

When the Aga is Doing the Naughty Thing that same red light flashes, rather than is solid.

usually an indicator that one of your element banks is blown or you have only just fired it up.  7 hours is plenty and shouldn't need to grab extra unless an element has failed.