teleswitch faulty

[SparkyTris]

surely the teleswitches are addressed by group, then there can be (at least) delays within that group.
Probably the groups are deployed geographically.
eg, group A switches for Orkney Islands. Group B for shetland. Group C for Caithness, etc etc.
Then the LW signal can enable group A.
Group A, (ie, all of Orkney)'s 7,000 teleswitches then start to pop on during the next few minutes according to their random delay. when the grid has settled down from that, the LW signal can arm Group B's teleswitches?
just a thought.
Im not too sure about the random delay. we have similar here, (different district of Orkney) and when the heating comes on about 8pm, the volts must dip about 20V judging by the dimming of the incandescents. I will meaure it one a these days. certainly feels like there is a massive concurrent load comes on. sometimes the office UPS pleeps to trim.

if the heating load is switched off suddenly, would the line voltage correspondingly kick up? or does it not work like that?

 

[bernardgreen]

switched off suddenly, would the line voltage correspondingly kick up? or does it not work like that?

If all the heaters were drawing current when the the TeleSwitch went OFF then there would be an increase in the line voltage, also a transient spike when the load was removed.

But by the time the TeleSwitch is commanded to OFF the majority of heaters will have been fully charged and will have switched themselves OFF

 

[SimonH2]

Taking various bits in no specific order.

From https://en.wikipedia.org/wiki/Radio_teleswitch
"Some suppliers also offer more sophisticated heating control using the radio teleswitch network. For example, Scottish Power 'Weathercall' and SSE's 'Total Heat Total Control' both dynamically vary the length of time storage heating is energised each night depending on the forecast temperature for the following day to help maintain a consistent household temperature."
So it looks ike the specific tariff mentioned is explicitly dynamic in timing to suite the prevailing/forecast weather.

The signal comes from the R4 transmitter at Droitwich in Worcestershire. It was "supposed" to have been discontinued some years ago, and will "definitely" go when a valve fails in the transmitter (according to the BBC), but you might imagine that there's a lot of teleswitches still in use and at some point the lecky industry is likely to find some way of persuading the BBC to keep the service going.
Ah, I see from the above link that they've negotiated a contract extension to at least March 2022 - and there are estimated to be around 1.4 million units still in service (as of earlier this year).

Yes, they are switched in groups - but I suspect quite large groups. I also suspect the groups are largely based around the geography of the electric board areas from many years ago.

Typically the contracts don't specify times, only that you'll get (for example) "a minimum of 7 hours at cheap rate, split into no more than 2 periods, between the hours of 10pm and 7am". That's because they used (still use ?) off-peak heating loads as a crude form of demand control - turning off some load if some surge in demand happens (or is expected to happen).
From observation, they can come on during the day as well - in the offices I used to work at, sometimes you'd hear the contactor pull in and be able to hear it humming. This was either a fault, or possibly a means of adding demand as an alternative to shutting down a plant temporarily.
From the above page "Teleswitching has also been used to help level out demand in areas where the supply network is close to capacity. In the 1990s, Manweb used such a system to provide different households with different off-peak periods on a weekly alternating basis. By spreading out the high peak demand associated with electric storage heating in Mid Wales, the company avoided upgrading costs of over a million pounds, and £200,000 a year in reduced use-of-system charges."
So yes, the only way to know if it's "on" is to see if your loads are on, the contactor is pulled in, or see which way the indicator is pointing on the meter (the mechanical 2 register meters have a pointer that moves when a solenoid physically moves the drive mechanism between the two registers).

Yes, if you are on the end of a long line, then the voltage changes when the loads switch on/off. I recall many years ago a consultant who was working in our department at work was "a bit peeved" about the voltage changes - significant dips when all the storage heaters in the hamlet turned on, and high voltages when they were off. I imagine that in some situations, the DNO might not be able to get both extremes within their allowed limits.

 

[JohnD]

IIRC, if you have a teleswitch and it doesn't receive the radio signals, it reverts to a timeclock.

It is going to be very difficult for you to work out what's happening if you don't visit, and the tenant can't help you.

Isn't there an electrician with local knowledge?

 

[StephenOak]

Typically the contracts don't specify times, only that you'll get (for example) "a minimum of 7 hours at cheap rate, split into no more than 2 periods, between the hours of 10pm and 7am".

So yes, the only way to know if it's "on" is to see if your loads are on, the contactor is pulled in,

On those contract terms, the service will switch on after 10pm, but to give a full seven hours it must switch on by midnight.

he is unable to sit there all day watching the lamp/looking at the meter/listening for the clunk!

So the tenant would need to monitor the lamp for a maximum of two hours. If he has to be up at the crack of dawn, not going to bed until midnight may be a problem I doubt the start will be delayed until then every night.

 

[SimonH2]

The times were only given as examples, I don't recall exactly what times I've seen (a long time ago). An alternative would be one of those old-fashioned mains powered clocks that only runs when the power is off - set it to 12:00 and see how long it runs for overnight.
The high-tech version is a monitoring device that will record the time/date each time power goes on or off.

 

[StephenOak]

The times were only given as examples,

Oh sure. But, AFAIUI, these systems are all something like that, with the cheap rate period being overnight. So it must start something like 10, 11, 12.

And the key point was that it does not need to be monitored all day but for an hour (or two or three). Not something you want to do every night but feasible for a day or so.

 

[SUNRAY]

One of my tenants had a problem which they referred to the agents...blah blah blah resulted in a massive bill for me but turned out to be a faulty Teleswitch.

Fine for a short while all was fine but when the heating failed again they were told to listen for the clunk. I visited several times to ensure things were as they should be. The contactors on the rear wall of the block of flats took about 5 minutes to come in.

 

[Lectrician]

IIRC, if you have a teleswitch and it doesn't receive the radio signals, it reverts to a timeclock.

It is going to be very difficult for you to work out what's happening if you don't visit, and the tenant can't help you.

Isn't there an electrician with local knowledge?

Not the standard teleswitches. If they missed, they missed. Occasionally we get calls saying the storage heaters didn’t heat, but from several different people, almost as though that group code didn’t switch.

As for random delays. That’s a myth. If your group is switched, your group comes on.

 

[jg321]

As for random delays. That’s a myth. If your group is switched, your group comes on.

I happened to be in the meter cupboard in an old flat I was in at the time of switchover. Around 30 flats, and they didn’t all switch at once, in fact it took around 20 for them all to switch. Seemed to be like the frequency of popcorn popping, one, then a little cluster, then a gap, then another one.

I thought this was the “random delay” in action?

 

[SparkyTris]

Isn't there an electrician with local knowledge?

Used to be... used to be.... an upstanding uncorruptible chap who knew the district, knew everyone, read the meters, kept it safe, provided value for money. Like the resident GPO man.
all gone now.
now they spend a fortune sending clueless young numpties out on daytrips with vans via roro ferry and its all a pile of w*nk.
still on the plus side you get someone "reading the meters" who cannot sniff out energy theft when its literally staring them in the face.

 

[SparkyTris]

Thanks all for input, I guess I will have to rig something up to automatically log the times, shouldnt be too hard.

 

[SparkyTris]

does the signal actually come from Droitwich? I had a vague feeling that there was another 198 LW tx in Cumbria to stretch up north. but maybe the switcher signals are only on the droitwich transmitter.
seems a bit of a long shot especially in daylight.

 

[jg321]

Thanks all for input, I guess I will have to rig something up to automatically log the times, shouldnt be too hard.

I like the “plug in mechanical timer and see how far it advances” approach, especially as my brain starts thinking up all kinds of weird and wonderful solutions. Sometimes going back to basics is better!

 

[bernardgreen]

I had a vague feeling that there was another 198 LW tx in Cumbria

The time signals from Cumbria are not involved with TeleSwitches, LINK

The TeleSwitches use sub carriers on the the BBC Long wave 198 kHz signal. Radio 4
LINK

I recall there a some low power 198 kHz infill stations but have no idea if the data signals are transmitted from them