DIY Doctor

Storage Heater: Not working

Postby seank » Thu Dec 15, 2011 12:07 am

I have the following storage heater which isn't working, the last time it was, was during the severe winter weather late 2010 and earlier this year.

Heatstore HSX724 (input rating 3.425 KW / 24 KWh)

The outlet for this particular heater is non-fused, however the others are actually fused. I have noticed a hairline crack running through it (rubbed dust into it to make more prominent in photo), obviously I will have to replace this but am not certain whether this should be a like-for-like replacement or fused as the other heaters are.

Initially I thought it might have been the internal overheat cutoff that may have been triggered, however this wasn't the case. I then checked the heating elements connections and noticed a build up of dust from the bricks which was actually inside the contacts. Believing this dust was insulating the contacts I cleaned these out, still nothing.

Using a non-contact Fluke voltage detector pen, I've been able to ascertain that there is infact no live feed on the load cable from the outlet. Based on this I can only guess there is either a continuity fault or with the actual MCB (although this hasn't actually tripped nor shows any signs of damage). Fortunately I have crawl space access and checked whether the cable run has been damaged, which it appears it hasn't.

MK Consumer Unit (split load)
Lower load which is Economy7 night rate is populated with;
1 x LN6420s 20A 4 Pole
1 x LN6220s 20A 2 Pole
5 x LN5916s 16A MCB (one for each storage heater and water immersion)

Before I consider calling in an electrician I have a couple of questions;
1) Should the outlet mentioned above be fused, as the other heaters are?
2) Is there any other test I can carry out myself to determine where the fault actually lies?
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Simply Build It

Postby ericmark » Thu Dec 15, 2011 9:21 pm

A 13A fuse will allow around 3kW since your heater is over 3kW using a FCU is not really an option.
As to fault finding this needs some knowledge of what you have and also your own knowledge. Cables rarely go wrong so more likely the fault is in the consumer unit but working in a consumer unit is dangerous and although it may be a fault in the unit it could have been caused by the heater. So I would say time to bite the bullet and call an electrician.
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Postby seank » Sun Dec 18, 2011 8:43 pm

Thanks for the reply @ericmark much appreciated :) Apologies for my delay in responding (I didn't receive notification via email of your reply).

My local diy store didn't stock any 20amp switches with flex outlet on the facia, so managed to order a MK one off Ebay. At least thats nearly one job off the tick list.

In the mean time before I call in a qualified sparkie (need to save up some monies), I've decommissioned the heater by disconnecting the flex from the outlet and turned off the respective MCB switch.
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Postby sparx » Mon Dec 26, 2011 4:25 pm

Sorry for late reply but very busy with faults on heating systems/outside lights etc. (everything got to be repaired before xmas !).
May be a silly question but are you testing at night when nightstore half of board is alive?
You'd be amazed how many people don't think of that and try testing circuit during the day.
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Postby seank » Sat Dec 31, 2011 7:16 pm

@sparx I did indeed test the circuit during the nightstore period ;)

I'll be having another look into the fault in a few more weeks once silly season is over.
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