Block of 200+ flats, eleven single channel hot water timers blown this week alone.

[GBDamo]

Got called to "a flat in Manchester has no hot water" at 16:30 today and to be frank I was a little miffed to have to attend.

So arrives at site, spends 20mins finding parking, 30 mins finding the site contact, getting keys and then being informed that it was not one flat but eleven.

Have no idea what the supply is, big I'd guess, nor did I have access to ant distribution equipment, just a list of flat numbers.

So I go to the first one. The 16A MCB was off and was informed that "it goes bang if you try to turn it back on" which I took his word for.

So I worked back from the tank, element OK, thermostat OK, wiring OK however the timer was visibly burnt out.

Did a random sample of the other ten and of the four I checked out all had the same burnt out timer.

Due to the time nothing more was done and an assumption (I know?) made that all had blown.

The only other thing I did was to check the local voltages and all were 236-7V and steady, for the brief time I observed.

These flats were all over, not just one floor so unlikely to be from a single phase or distribution board.

The tennants all made the same complaints of flickering lights and one long recent power outage.

None of the staff had any knowledge.

----es me off that there is nobody on site with any ownership, or understanding of the buildings and their systems, there are two blocks approx 400 flats for christ sake.

I'm half tempted to just replace the controllers and note there may be underlying issues that need further investigations.

How would you guys approach this?

 

[LukeD]

Most certainly not replace the controllers .without a lot more testing Unless a whole batch is crap etc ? First port of call would be to check if the controllers have been fitted correctly .Could be lose terminals ??

 

[freddo]

11 is quite a large number to all fail at once! What is burnt on the timers? Overheated or blast damage? What is the make/model?

 

[GBDamo]

Most certainly not replace the controllers .without a lot more testing Unless a whole batch is crap etc ? First port of call would be to check if the controllers have been fitted correctly .Could be lose terminals ??

They're all, the four I checked, sound and correctly wired.

My concern is that the recent power outages have had something to do with it but with out communication with whomsoever resolved that issue, if indeed they did, and to confirm there is causation not just correlation then it's just stupidity to proceed, I know that.

It just baffles me that these building, under the management of a bunch of kids more interested in filling "units" than the safety of the tenants, are expected to manage themselves and you as a tradesperson should just be able to come in and "fix it".

Does anybody there even have the knowledge to comprehend that the have a potentially dangerous situation?

The more I think about this the more exasperated I get.

 

[GBDamo]

11 is quite a large number to all fail at once! What is burnt on the timers? Overheated or blast damage? What is the make/model?

Blast, and they're Sangamo PSS.

The pictures I have a terrible but all have charring at the terminals and in the back box.

 

[DPG]

Power surges? Loose neutral?

Maybe ask some of the flat owners if they have had any other electrical items pack up over recent months.

 

[LukeD]

so a good brand . .Something is loose ??

 

[James]

Best guess, loss of neutral
but as said before, some proper testing over time might be required.

if you change them as requested, ensure that on the invoice you recommend an urgent assessment of the building supply and distribution wiring as you believe there may be an underlying fault that caused the failures

 

[freddo]

Would expect a few more items blown up not just the hot water controller
though?

 

[Lucien Nunes]

It is often possible to identify the root cause from close forensic examination of the damage. Is there any way you can get and post high res pics and / or get a sample open on the bench and take some measurements?

Terminal burnout is not normally caused by a supply fault like a floating neutral. It is more likely to be from incorrect installation or faulty units. Overvoltage will usually kill the internal DC supply dropper and one can often tell from which components failed in which way, whether it was a 'surge' or a long low overvoltage from a floating neutral.

 

[GBDamo]

It is often possible to identify the root cause from close forensic examination of the damage. Is there any way you can get and post high res pics and / or get a sample open on the bench and take some measurements?

Terminal burnout is not normally caused by a supply fault like a floating neutral. It is more likely to be from incorrect installation or faulty units. Overvoltage will usually kill the internal DC supply dropper and one can often tell from which components failed in which way, whether it was a 'surge' or a long low overvoltage from a floating neutral.

Your quite right, it's time to get CSI on it.

The fact these faults have occurred across most floors leads me to lean towards a supply issue or early distribution issue.

I'll try to get back there today and swap out a couple, get some better pictures and do an autopsy.

 

[plugsandsparks]

Might be worth checking the rating of the controller against the load of the immersion, just in case they are maxed out

 

[Mikegh]

Must be supply overvoltage

 

[GBDamo]

Might be worth checking the rating of the controller against the load of the immersion, just in case they are maxed out

That's on my list, cheers.

 

[Julie.]

I would contact the manufacturer, ask them if an almost 6% failure rate is normal, wording the conversion well, I have no doubt they will ask for one of the failed units and do the post mortem.

Especially if you highlight that even if there were some form of supply problem, it didn't impact anything else other than their timers, nothing from other supply equipment/other makes of timers through to sensitive electronic equipment, only their kit.