Using a fan heater? - Take care!

[Barclaybasher]

This week a customer rang to say that a 2kw electric fan heater had cracked a 22mn thick marble hearth it sat on.
In 40 years I've never heard of such a thing happening.
The customer had put the heater on then 'forgot about it' for 2 hours. The hearth was so hot even 300mm in front of it that it could burn you.
He was a vehicle exhaust manufacturer and still has access to a thermal imaging camera on which he will measure the temperature on re-running the same conditions. He, like us, is concerned at the temperatures reached and we have already contacted the manufacturer.
I post this on here to warn against leaving a fan heater unattended in a van where there is so much that is combustible.
If you use a fan heater on hook up use the lowest heat setting - most heater have 2, high and low.
Stay safe

 

[Figaro]

Faulty product surely ?
Where it sits should never get that hot.
Who was manufacturer ?

 

[Barclaybasher]

Faulty surely ?

We don't think so - the customer thinks the fire needs a plate to deflect heat up from the hearth.

Edit....a 2kw fan is basically a heat gun...don't put your hand close to it on full to test it....

 

[Pausim]

Also make sure the heater has a safety cut off if it is knocked over. If not I would bin it.

 

[GWAYGWAY]

I take it that the thermoplastic moulding that a fan heater is made of had melted to a gooey blob on the worktop. That report sounds like BS to me. Proper heat gun for stripping paintwork might do it left directly pointing at the surface, but that is a different beast . There would be reports of building burning down all over the Place.

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[Barclaybasher]

I take it that the thermoplastic moulding that a fan heater is made of had melted to a gooey blob on the worktop. That report sounds like BS to me. Proper heat gun for stripping paintwork might do it left directly pointing at the surface, but that is a different beast . There would be reports of building burning down all over the Place.

The issue won't be resolved until it is tested. The hearth was so hot that it would injure a bare foot for example. The heater did not itself overheat just the surface it was heating - in this case marble.

 

[Mikeco]

Sounds faulty to me, I have a fan heater set back under the units in the van and have used it in that position for the last 6 years. It sits on a piece of carpet as well so would know if it gets hot.

 

[Lenny HB]

I really don't see how that can happen fan heaters just don't get that hot. Difficult to even use on heat shrink sleeving I have to get the heat gun out for that.
Sounds like he's trying it on hoping for compensation for the hearth he has damaged by other means.

 

[Barclaybasher]

I really don't see how that can happen fan heaters just don't get that hot. Difficult to even use on heat shrink sleeving I have to get the heat gun out for that.
Sounds like he's trying it on hoping for compensation for the hearth he has damaged by other means.

The customer maufactures vehicle exhausts and has said he does not want the hearth replacing, just concerned at the temperature it reached.

 

[Lenny HB]

The customer maufactures vehicle exhausts and has said he does not want the hearth replacing, just concerned at the temperature it reached.

Still seems odd, could the air flow have been restricted and the thermal cut out failed to work.

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[Oldbob]

Where is Scully any Mulder when you need them !!

 

[Barclaybasher]

Received from customer this morning

Temperature of Marble hearth:

75mm from fire 97 degrees Centigrade

125mm from fire 78 degrees Centigrade

Passed to manufacturer, obviously not expecting any reply until the New Year

 

[SpeedyDux]

You start to wonder about some of the very cheap imported fan heaters. I wouldn't leave them unattended.

Anyone can put an EC mark on them or claim BS compliance until trading standards actually tests them.

 

[Allanm]

Has he measured temperatures from another fan heater and compared them?
Marble isn’t really suitable for using as a hearth for anything other than decoration as it cannot withstand high temperatures without the risk of cracking, which has happened in this case.
It may be that there is nothing wrong with the heater rather it could be the fact he put it on an unsuitable surface

 

[Barclaybasher]

Has he measured temperatures from another fan heater and compared them?
Marble isn’t really suitable for using as a hearth for anything other than decoration as it cannot withstand high temperatures without the risk of cracking, which has happened in this case.
It may be that there is nothing wrong with the heater rather it could be the fact he put it on an unsuitable surface

Would you place your bare foot on a surface that hot though?

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[Richard n Ann]

Common sense dictates you shouldn't put anything close to the outlet. Our wall hung fire place with 2kw fan heater needs 300mm space in front of it.

Reminds me of folk who have a/c fitted and then complain of a cold draught ?

 

[63720]

IME of some of the fan heaters on sale now a significant amount of their radiated heat actually comes from the plugtop.

 

[Allanm]

Would you place your bare foot on a surface that hot though?

No of course not, but that’s not the issue. But even at that heat, unless the marble was already damaged, it shouldn’t crack.
We used to have a marble topped table and we regularly put hot kettles and teapots on it when they were at it near boiling point. No cracks.

 

[Raul]

My wood stove sits on a piece of marble 22mm thick serving as a heart. The stove legs are about 125mm height and weighs 130kg empty. The temperature in the fire box exceeds 600 deg C as is got a secondary burn, very efficient and hot. The marble has a brick surround to the sides and back. It gets hot and I will never dare touch it with bare skin if the fire is on.
So marble can take some heat, you can do stakes on it before it cracks.

 

[Barclaybasher]

No of course not, but that’s not the issue. But even at that heat, unless the marble was already damaged, it shouldn’t crack.
We used to have a marble topped table and we regularly put hot kettles and teapots on it when they were at it near boiling point. No cracks.

In 40 years I have sold thousands of marble hearths and they can crack with the heat from a real fire if not fitted correctly or if subjected to intense heat. In this case the customer admitted to leaving the fan heater on full (by mistake) for 2 hours. 2 hours at the temperatures he recorded would be enough. Nevertheless it's a first for me.
As I said earlier it has been reported to the manufacturer of the fire who no doubt will investigate in the New Year.

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[pappajohn]

Also make sure the heater has a safety cut off if it is knocked over. If not I would bin it.

Which is most likely what happened here, air directed to the slab.
Like any fan air is directed away, not around, the fan so the surroundings would be relatively cool in normal use. .