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Topic Title: Fault finding on economy 7 heating system
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Created On: 10 February 2013 02:26 PM
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 10 February 2013 02:26 PM
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earthing

Posts: 65
Joined: 17 December 2008

Hi,

I am attempting to fix an economy 7 heating system. The problem is that the five heaters do not operate at all.

The storage heaters are all simple operation manually operated units with no auxiliary controls. They are Mathius. I have verified the operation of the heaters via temporary supplies and all five are ok.

I don't fully understand the system but in the distribution units there are two boards.

One board which feeds standard circuits and a separate board for the heating including water. All 60898 mcbs.

There are two contactors in the board. And separate radials for all 5 heaters, the water heater and the contactor.

Funny thing is the economy 7 board is fed via 16mm double insulated tails in parallel with the incoming tails from the dno's meter. I wasn't expecting that.

Anyhow the five feeds for the radial circuits are fed from the mobs to the contactor supply side. I was expecting a totally separate supply with its dedicated meter.

However at the intake the meter is a digital type which says dual tariff. I guess it has a built in digital timer? Another thing I wasn't expecting was the mcb marked contactor goes down to the intake position where it feeds a 13amp spur. This then goes in to the meter via a 6mm double insulated tails. There are two tails from the spur which enter the meter neither are marked. I have traced the other cable in the spur back to the live control side of the contactor.

If I turn the mcb marked contactor on and use a fly wire to connect to the control side of the contactor the contractors energise and the system operates. I don't really understand that.

I hope you can understand my explanation and help me understand this problem.

Daniel
 10 February 2013 02:37 PM
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slittle

Posts: 3553
Joined: 22 November 2007

The spur is providing a supply through the meter's "timed contact" I suspect if you were to short out the two 6mm tails with the spur turned on then the contactor will operate.

If it does there is an issue with the meter and if it doesn't check the fuse in the spur. I'm guessing that the spur is only there to provide a means of isolation between the heating system and the meter's timed contacts.

Have a better look at the spur and confirm it's not got live and neutral there but in fact live and a switch line back to the contactor coil.

Stu
 10 February 2013 03:00 PM
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Jaymack

Posts: 4665
Joined: 07 April 2004

I had a similar fault with economy 7 not working at all. Eventually found that the meter was not switching. Some tariffs have a boost period during the day, nice for testing!

Regards
 10 February 2013 04:32 PM
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alancapon

Posts: 5789
Joined: 27 December 2005

Originally, the two-rate meter had a separate "Teleswitch" which switched the tariff rate at the appropriate times, and also had a 100A auxiliary contact, which would be used to switch the "economy 7 only" circuits. Meter manufacturers now make the Teleswitch part of the meter for various reasons, and there is no longer any room for the 100A contactor. The answer is therefore for the customer to use their own contactor to switch the load. The DNO / Meter Operator will provide the contactor coil supply via an auxiliary relay in the meter, often via a fused spur. This allows the customer's contactor to be isolated, and offers overcurrent protection as well.


Regards,

Alan.
 10 February 2013 09:28 PM
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earthing

Posts: 65
Joined: 17 December 2008

Hi guys thanks for all the responses. I have tested the fuse and the continuity of all of the conductors and no problems there. I am going to call WPD tomorrow and see wether they can come and verify the meter is functioning correctly.

Does anyone know how to post pictures or wether that is possible as I have taken pictures of all of the equipment which might help some diagnosis!

I will investigate the line/switched line Stu thanks for that.

Thanks to all hopefully I can get to the bottom of it now because the client has had three sparks fail him so I have to uphold the trades integrity I feel!
 10 February 2013 10:16 PM
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ady1

Posts: 766
Joined: 19 April 2005

There may be a button on the meter that scrolls through the tarrifs, date, time etc... if the time is wrong and the contactor is on a timer, that could be causing the problem.

Regards
Ady

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Resistance is futile.
 14 February 2013 01:43 PM
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earthing

Posts: 65
Joined: 17 December 2008

Hi guys,

Swalec came out on Monday and replaced the multi tariff meter. Customer called me Tuesday to say its all up and running so it was theatre after all!!

Thanks for your help,

Daniel
 14 February 2013 05:25 PM
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Rulland

Posts: 472
Joined: 11 April 2008

Glad I don't have an Itoy's spell checker on my back!........

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Those who make no mistakes do very little work!!......
 14 February 2013 07:32 PM
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ArthurHall

Posts: 736
Joined: 25 July 2008

I had a similar fault in a hotel a few years ago the difference was the low rate supply was on all the time, after a couple of weeks every thermal cutout had operated in each heater.
 15 February 2013 10:07 PM
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maltrefor

Posts: 121
Joined: 01 November 2009

Originally posted by: alancapon

Originally, the two-rate meter had a separate "Teleswitch" which switched the tariff rate at the appropriate times, and also had a 100A auxiliary contact, which would be used to switch the "economy 7 only" circuits. Meter manufacturers now make the Teleswitch part of the meter for various reasons, and there is no longer any room for the 100A contactor. The answer is therefore for the customer to use their own contactor to switch the load. The DNO / Meter Operator will provide the contactor coil supply via an auxiliary relay in the meter, often via a fused spur. This allows the customer's contactor to be isolated, and offers overcurrent protection as well.





Regards,



Alan.


I have just finished an Economy 10 installation this evening where we had to provide a SFCU, a contactor, a programmer to control the system & Henley blocks to connect into the supply from the contractor switch newly installed along with the new 2 rate token meter by SSE !!!
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