Faulty storage heaters

[Selfmade]

Hi folks


Was called to three storage heaters which have stopped working (all storage heaters in property). Two of the connection units into which the heaters are wired have neons, and the customer says these light up when the storage supply is on over night (so problem is not with supply or house wiring). She said she was away over Christmas and switched off the heaters and after she returned and switched them back on, two of them did not heat up. The other one stopped working more recently.


I have checked continuity through two of the heaters and got a path through all devices and wiring except the thermostat. So I have concluded that it is this which is at fault. What seems odd is that the thermostats have all broken within a few weeks of each other. I wondered if anyone had any ideas about why this may have happened? Also, the customer is a tenant and said her landlord (I believe without even looking at the heaters or getting a spark to do so) said that it must have been something she (the tenant) had done that had caused the fault. I find this rather implausible. Does this seem likely?


Would be grateful if anyone could cast any light on this.


Sam

 

[Welchyboy1]

Sounds like the thermal trip has opened and needs to be reset, some models have a thermal link that may have blown or may need new heating elements, test these with an ohmeter

when i service storage heaters i put a plug on the flex and plug them into an extension so i can get them powered up and know exactly whats going on

 

[itselectric]

I dare bet it is the thermal link, caused by customer drying clothes on them. OH I am cynical.

 

[BES]

I dare bet it is the thermal link, caused by customer drying clothes on them. OH I am cynical.

Do people really do that can't believe even after telling them more than once

 

[Selfmade]

Thanks folks, really useful! I will look up the models and see if they have thermal trips or links. I certainly couldn't see or feel anything that could be reset, so maybe a link rather than a trip...

Welchboy, I did test the elements with my MFT on continuity function - got ~23 ohms on one heater and ~34 on the other, which I thought was about right for an element?

 

[cotty]

The question is elemental my dear Watson....

 

[tazz]

Around the 30 ohm mark is right for heat elements, look for the center thermal reset, just press it, and you will feel it click.....as stated cloths are the classic to trip these

 

[HandySparks]

Thanks folks, really useful! I will look up the models and see if they have thermal trips or links. I certainly couldn't see or feel anything that could be reset, so maybe a link rather than a trip...

Welchboy, I did test the elements with my MFT on continuity function - got ~23 ohms on one heater and ~34 on the other, which I thought was about right for an element?

You can do the calcs yourself:
Watts=V²/R

So, 23ohms gives 2300W and 34ohms gives 1556W. Sounds reasonable.

 

[Welchyboy1]

Thanks folks, really useful! I will look up the models and see if they have thermal trips or links. I certainly couldn't see or feel anything that could be reset, so maybe a link rather than a trip...

Welchboy, I did test the elements with my MFT on continuity function - got ~23 ohms on one heater and ~34 on the other, which I thought was about right for an element?

Generally the elements will differ a little but if their knackered you will get an open or really high reading

the thermal link usually looks like a silver cylinder about the size of a plug top fuse with two little tails coming off each end in a U shape

 

[Buckfast]

Would agree with sentiments already posted regarding thermal cut out/link and also the usual clothes put over heater. Generally when testing storage heaters assume each element has a resistance of 68 ohms (Rule of thumb). Divide this by number of elements inside heater, as an example 3 elements in heater = 68/3 = 22.6 ohms. Put meter across any element and this is the reading you ought to obtain as all elements in parallel. If reading higher ie 34 ohms, heater has one element open circuit. The readings you have obtained appear to indicate a 1.75kW heater (2 Element) and also a 2.5Kw heater (3 Element). What make and model of heaters are they?.

 

[Selfmade]

Hi folks, thanks for all the helpful replies. I have been trying to find instructions (preferably with diagrams) but neither the user or installation manuals tell you how to reset the cut-out. I had a good look/feel of one of them and couldn't get anything to 'click'. I will probably phone Dimplex tomorrow, and also do some calculations to check the elements have the correct resistances as suggested by Buckfast and HandySparks above. (Shouldn't be complicated I know but my brain stops working when I'm tired!) The heaters are Dimplex and the models are XL12N, XL18N, and XL24N.

 

[jaypp]

as previous posts re thermal cut-out. people will always deny covering them (with a story as an alibi) as it states clearly, 'do not cover'! had one first day back after new years. the reset wasn't obvious and if memory serves me correctly, was what looked like a male spade connector (angled upwards @ 2 0'clock) under controls.

left hand dial i think

 

[Resu]

Ok cut out is raised bit circled in red (borrowed pic) if it doesn't click you either haven't pushed the right bit or it hasn't tripped!

 

[Selfmade]

Hi folks


Thanks all, especially Resu for the pic!


Just had a call from the customer - it seems I have reset one of the cut-outs without even realising it and that heater is now working! I will of course have to return later to fix the other two, and I would like to be sure I know how to do so and that the last one wasn't just down to luck.


Resu - the part you have circled was certainly the part which was open circuit. I tried pushing the raised bit in all directions as I had a feeling it might be the reset button, but I'm pretty sure it never clicked. Which way should I push it? Downwards? Or away towards the wall? Sorry if I am being an imbecile here! This is the first time I've worked on storage heaters!


HandySparks and Buckfast - thanks for your calculations and tips. The XL12 N is a two element heater and is the one that read ~34Ω. 68/2=34, so exactly as you said to expect. The XL18N has three elements and read ~23Ω. 68/3=22.6 as you said, so close enough.

 

[Selfmade]

The question is elemental my dear Watson....

I did a chemistry course some years ago, but it was elementary...

 

[Selfmade]

Just been back and reset the remaining two cut-outs. Both cut-outs clicked and I got continuity right through both appliances. However neither thermostat clicked even when turned right down - I am hoping it is just because the rooms were a bit chilly, but I have advised that the thermostats may be faulty in which case the cut-outs will just trip again. The thermostat on the heater I fixed yesterday did click, and the property was a bit warmer then, so here's hoping...

Thanks again for all your help folks!

 

[Silly Sausage]

Take a hair dryer/hot air gun next time.

 

[Resu]

Just been back and reset the remaining two cut-outs. Both cut-outs clicked and I got continuity right through both appliances. However neither thermostat clicked even when turned right down - I am hoping it is just because the rooms were a bit chilly, but I have advised that the thermostats may be faulty in which case the cut-outs will just trip again. The thermostat on the heater I fixed yesterday did click, and the property was a bit warmer then, so here's hoping...

Thanks again for all your help folks!

Sorry for late reply, glad you worked it out mate. Had the same trouble ourselves recently, won't be forgetting where they are on these heaters for a while!

 

[Selfmade]

Thanks again folks, and no worry re lateness of reply! I haven't heard back from the customer, so presumably all is still well with the heaters!

Sam

 

[01jasjon]

Hi guys, can anyone give me some advice to why one of my storage heaters has stopped working? It's a creda 79161C. Got six heaters in total throughout the house. Switched them all on recently and one of them isn't working. What are the main things to check (what do they look like) before deciding just to buy a new one. Thanks in advance