Archive for July, 2017

How to stay safe at home….

You always feel safe at home. Maybe you get your gas boiler serviced regularly, maybe you have smoke detectors, with new batteries fitted regularly? Above all you get competent professionals to install your new cooker, and also the new gas hob in the kitchen.

When was that done, when was your gas supply system checked? If you were in rented accommodation, the landlord is legally obliged to have it checked every year. But if you own your own home, there’s no obligation to have anything checked on a regular basis. Even if you have lived there 30 years. But things can go wrong.

Take your own precautions

Yes I did that. I installed a carbon monoxide alarm system, alongside the smoke detector, to check whether the gas boiler flue had been blocked, and CO was building up in the boiler area. I installed a flammable gas alarm to monitor the kitchen, in case a gas ring was inadvertently not switched off, or had a fault. Not expensive, maybe £30 each.

For many years the flammable gas alarm worked fine – in other words it just sat there, and never said a word. Then it started going off, whenever there was any wine added to the stew on the hob, whenever there was any bread dough rising in a low oven, and whenever the windows were sprayed with a solvent cleaner. Eventually the alarm started going off so often – for example when the kettle boiled and steam was seen rising past the detector, that this was the final straw. It must be worn out, or faulty, it is just giving too many false alarms. So the gas detector was discarded.

Smart metering

OK I’m a real geek, I like the idea of monitoring the gas and electricity consumption, so readily joined in the offer for Scottish Power to install new “Smart” meters free of charge. Its part of a Government scheme, but means the meter readers don’t trample all over your home. That is the real benefit.

Meters installed aok, but just the final safety test – oh dear, there seems to be a slow gas leak somewhere in your system, its not major, but it falls outside permitted levels. Now I have to call out a ‘Gas Safe’ engineer to check the system, and have to pay for that (!) .

You know the problem, for the first two appointments no-one turns up. For the third, he is called away for urgent safety checks on a tower block, otherwise the tenants will all need to be evacuated. Finally, Saturday afternoon, I get an engineer to visit: this is Simon from JPS Plumbing and Heating in Winchester.

A hob problem

Simon very quickly locates the area of the problem, it’s in the supply to the ten year old gas hob. If the leak is in the hob itself, it would not be economical to repair. There are only two joints underneath to check, so Simon lies upside down in the oven space to feel the state of each one. Now the leak checks show the leak rate is smaller, and within the allowable tolerance – only a sixth of what can be permitted.

He is actually surprised to have made such a difference, compared to the initial leak test, so re-checks the joints. Now the supply pipework where it joins to the hob falls away completely. The steel 90 degree bend feeding the hob has sheared off between the thread holding the pipework and the bend. Although this newly created ‘nut’ unscrews, it immediately falls apart in two halves, in what could be described as a brittle fracture.

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This is supposed to be a 90 angle steel union. The thread holds the fitting on the copper pipe down onto the blue looking seal. The whole thread has cracked off, maybe its a very short length of thread, but it was not strong enough to take the stud fitting on the hob.

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Side view of the fitting, where the hob would be above. The cracks and failures are obvious.

The photos above show the union, with its broken thread, and the crack around the pipe, which had obviously been growing, and leaking, over the years. The false alarms the gas detector had given were just saying “Whatever else you are doing, its made the gas that’s leaking exceed the thresh-hold to trip my alarm”. Even the steam from the kettle was just making the gas rise faster on a route past the detector.

It would seem the elbow had been twisted too tight onto the hob, necessary to get the entry angle for the supply pipe to fit in the right direction. Maybe it was pulled too far on installation?  Or the sealing washer (the blue bit) was not flexible/compressible enough?

Lessons learned….

That union could have failed catastrophically, at any time, but maybe in the middle of the night, and filled up the kitchen with gas. When the boiler ignited at 7am, it would have had a willing flame ready to set off a really big bang.

Listen to your alarm sensors, and don’t ignore persistent false alarms! Buy a new sensor if the old one seems to be getting unreliable.

Get your gas supply around the house checked regularly – how do you know that even a properly installed hob – like we believed ours was – has not developed a fault, over 10 years?

Call a reputable plumber, a Gas Safe engineer who knows what he’s doing, like Simon from JPS Plumbing! Don’t just use a guy down the road who’s installed a few gas fires….

Postscript – the Hob itself

It is very likely that the 90 degree bend in steel that failed was supplied as an integral part of the hob itself, and not as a component by the original gas installation engineer. The hob was a PROline PGH460GL-U black glass top hob, with four burners, purchased via Currys. ProLine is reported by UKwhitegoods.co.uk as a trading name/brand owned by the retailer Comet, who sourced Eastern European or Chinese domestic appliances at the lower end of the market, and sold these via many other retail outlets. Particularly after the break-up of Kingfisher Group and transfer of the Comet business to Kesa, the quality of their product supply was not good.  The products were also still sold through the Darty chain of shops in France. This was apparently from 2006 onwards: the manual that came with this hob is dated 2007 and was originated by Kesa in Hull. PROline products are no longer sold, the business has closed.

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A ProLine gas hob of the PGH460GL-U type described here