Storage heater questions

ywlgy

Hi,

My flat has three storage heaters. Two of them are standard input/output version so I know how to use them. However the third one confuses me. The model is Creda 70315/SFHA24. It must be so old that even Creda website does not have its manual. Shame! It has two switches: one for fan and boost and one for off-peak storage. The control panel has two knobs: one for room temp and one for OFF/BOOST/COMFORT/COMBI.

1. Should the light on off-peak switch be on all the time during the off-peak period? It's on at 11pm but then off after midnight, not sure about after that. Is this normal?

2. Should I also switch on the peak switch? I've tried switching on the off-peak one and it can store heat normally. But I am not sure if the storage heater needs fan to release heat and power to control temprature.

3. I set the room temp to minimum but the heater itself is quite hot in the morning. I don't want it to store too much heat but there is no input control like others. I am worried it keeps storing heat all the night.

4. Which mode OFF/BOOST/COMFORT/COMBI should I choose? Now it's on OFF. BOOST will activate the fan heater. I am not sure about COMFORT and COMBI.

Gerry1

1. Yes. You're probably in the South East Region where the E7 hours are 10:30pm - 12:30am and 2:30am - 7:30am GMT.

2. No ! This will use full price electricity and is a last resort for use only if you have goofed (e.g. forgotten to set it the night before), there's been a sudden cold snap, power cut or you've been away. Make sure you always send monthly meter readings or you may suffer bill shock when the Direct Debit doubles.

3. Essentially there will be an input control and an output control, albeit with some bells and whistles as it's not just the basic box of bricks. As you probably know from your other two heaters, the input has to be set the night before and you have to be a weather forecaster and adjust it for the predicted occupancy hours the next day. It controls whether the bricks end up lukewarm or scorching hot and it will probably have no immediate effect during the day, you just have to hope you did get it right the night before. Needless to say, set it too low when you go to bed and it'll be chilly later on the next day, set it too high and watch the bill rocket.

The heat output control is a flap that can be opened or shut to give rudimentary control over the heat output. Simple versions have just two positions, permanently shut or automatically opening under the control of a simple bimetallic strip as it the bricks cool down.

Your version is a bit more clever, having a fan that can move the air better than simple convection, and it may have a clever thermostat or a timer, but the principle is the same, it allows more air to flow through to give you a bit more heat as it loses its mojo.

If all else fails, you can use peak rate electricity to give immediate heat. It should be used very sparingly, e.g. if you've set the heat input low because you'll be out all day and will return late in the evening when you only need a quick boost before the E7 kicks in.

4. You may have to experiment to work out how these terms match up to your input / output control labels. It sounds like you may have confused the room temperate (output) control with the input control.

Basically, the heat output control won't control how big a gulp it takes overnight. That's the job of the heat input control but I suspect it may be set too high because you don't recognise it for what it is.

If turning the wick up or down during the day soon makes a difference, you've found the heat output control. (That is, unless you've managed to turn on the peak rate boost: look at the electricity meter and see if it's burning up the expensive units like there's no tomorrow.) Similarly, if a knob feels 'mechanical' and you can feel or hear a slight characteristic thump as the flap closes, it's the heat output control.

As a rule of thumb, turn up the heat input control if you're getting chilly late in the day and the output control doesn't make sufficient difference. Turn the heat output control down if you're too hot in the morning. Remember that the heat input control makes a difference tomorrow, the heat output and boost controls make a difference now.

jk0

Mostly agree with what Gerry said. I did find a circuit of the heater here: https://www.manualslib.com/manual/623208/Creda-70305s.html?page=6#manual


You can see that there is a room temparature sensing thermostat in the off-peak circuit. So the thing should increase and decrease its storage according to the weather, if you set it up correctly.


As far as I can see, you have three output options:


1.) Passive discharge of the overnight stored heat.
2.) Fanned discharge of the overnight stored heat.
3.) Fanned discharge of the overnight stored heat plus additonal heat from day rate.


I think I had one of these in a flat about 20 years ago. The fan system was a complete dead loss, and I was cold even with option 3. Your best bet is to get an oil filled radiator to top up in the evening.

Gerry1

Eureka ! :j

Here's the Owner's Manual.

There is no heat input control, it's automatic, which is probably quite sensible. If it was too warm or cold in the morning, people would turn it to minimum or maximum but nothing would seem to change. They wouldn't understand that the change wouldn't be noticed until the next morning. They'd also be changing the heat output control, so it would result in endless confusion.

So just turn the output to low when you go to bed, turn it up during the day so that you're comfortable, and use the boost as little as possible to avoid massive bills.

jk0

Well done Gerry.


I remember now...


The input control required you to open the heater to change it, by turning a shaft with no knob. (Of course you can't do this when the heater is red hot! )

ywlgy

Thank you for your replies!

I am in north west where E7 should be 12:30-7:30am GMT. I am OK with the about 2.5 hours time shift (1:30am -> 11pm) but don't know why the off-peak supply is off after midnight. Last night I heard a slight thump from the consumer unit when the off-peak light is off at about 12:30. The meter is not accessible to me so I can't check it. Switches of other storage heaters do not have lights so I don't know if just the one in living room is disconnected or the whole off-peak supply is off.

The one in the manual is not exactly the same as mine but close. So the offpeak and peak circuits are separated, i.e. switching off the peak supply won't affect charge and discharge but discharge will be only passive.

I don't know how clever it is to automatically adjust the input and really don't want it to charge 24 kWh every night. I will keep the temp setting at minimum for 1 month and then get a meter reading.

jk0

If your storage heater is anything like my one was, I think you'll find the factory setting for overnight charge was rather low.


Yes, I concur with Gerry, that you should turn off the unrestricted supply.

Gerry1

You can check the switching times by making a free call to 105. If it's a radio teleswitch the times are usually +/- 15 minutes, but clockwork ones can drift.

The heater shouldn't draw the maximum 24kWh every night unless it's completely cold when the off peak supply is connected, e.g. the depths of winter or if you've turned the wick up to maximum.

If the meter cupboard is inaccessible because it's usually locked but is nearby, you might find it worthwhile to get an energy monitor. Most just use a clip on connection, but those that count the red flashes from the meter's LED are the most accurate. However, if you have the clip on type and clip it to the off peak supply you should be able to see when the supply is live and supplying the load.

Robisere

Do you own or rent the flat? I ask because we live in Sheltered Housing and our complex (all bungalows) had even older models of the same Creda heaters. As we are all elderly/infirm/disabled or a combination of all 3, we were at home most of the day. That meant keeping the heat on all day and by 4pm it was no longer even warm. In winter of course, that is exactly when it is needed. Eventually, via our previous MP (RIP Sir Peter, we miss you) and the Environment minister, we forced our landlord to fit gas central heating. It saved us a lot of money when our bills reduced by at least 40%.
That won't help you if you own your flat, but if you rent, you can ask your landlord to at least fit either a heater to match the others, or newer electric ones.