immersion heater problems!!! all 7 of'em!

[egginyourface]

Ive been called out to about 7 different jobs this week!! All to check why newly fitted immersion heaters were not working properly.

Its always the same thing. Plumber fittied new immersion heater and since then the water doesnt get fully hot or after the 1st bath the water wont heat up enough till the next day.

Every single one i go to i find that the plumber has turned thermostat up to the max trying to fix the problem causing cut out to kick in!

My job is as always to check the wiring is done correctly and no loose connections. I never touch the thermostat.:6:

What causes this luke warm problem??

Is it a mistake made by plumber, wrong sized immersion, wrong type etc??


Somebody please tell me as i would like to understand this

 

[TaffyDuck]

I appreciate what you guys are saying however for 15 years I have fitted immersions with nothing but the normal thermostat with no problems. These thermal cut-outs come in and they constantly trip out, so much so that several customers source the non thermal cut-out variety which are still available ( not sure if they are still being made or not). Accidents are tragic and I my heart goes out to the parents of that baby but if we are to cover this potential hazard we need something more akin to a quality tank stat fitted instead of a 1p bit of chinese tat as a safety measure.

 

[GLENNSPARK]

but fitting a non thermal cutout imersion heater is one thing Taffy.....interfering with an imersion heater that has a thermal cutout inbuilt/fitted is entirely another......

 

[TaffyDuck]

but fitting a non thermal cutout imersion heater is one thing Taffy.....interfering with an imersion heater that has a thermal cutout inbuilt/fitted is entirely another......

Point taken, although they would of course be exactly the same after. Is it a British standard that all immersions must have these fitted now?

 

[GLENNSPARK]

not 100% on that Taffy but i would imagine so yes....

 

[GLENNSPARK]

it aint just these imersion heaters that are subject to interference either....seen bodged up BS3036s quite a bit n all....

 

[Knobhead]

Just have a look on Google for the effect of hysteresis curves on thermostats.

Taught in “Test Methods and Reliability” 35 years ago.

 

[drew35]

I tend to find the new thermostats come set to low and need turning up one notch, but not to maximum. And the quality of some of the heaters now is dire, I hear it a lot now from people that the new heaters only last just over a year.

 

[Guitarist]

Extensive testing is now carried out to make sure that products only last just beyond the warranty period.

 

[Guest111]

My old apprentice ,who now works for a large firm called to see me on Friday just to let me know how he is doing,anyway he went to a job in Stockport and while he was there he noticed cover had been removed on immersion heater and asked customer where it was as it was unsafe and there were small children in house.Customer had apparently removed it as all he got was one shower then cold de to stat tripping,fully electric system as no gas maybe problem is more common than we realise.

 

[MarkieSparkie]

When presented with this type of "lukewarm" problem. I usually remove the thermostat to check that the correct length has been installed. In almost all cases I find a short 7" stat has been fitted where an 11" or 18" thermostat pocket is provided.

 

[oldtimer]

Guys
I worked for a Swiss controls company for 6 years and I worked on HVAC and DDC or BMS controls and I used to have problems with customers who would say your controls are crap they dont work and for me it was all about education and human nature . Because they did not understand how they worked it was easier for them to tamper or frig them to get a result and to me I can see the same pattern in the previous posts.

I was called out by a landlord who said the tenant is not pleased he had no hot water and he cant even get the boost side to work and sure enough when I arrived on site the off peak side (bottom of the tank) was cold and the boost (top of the tank) was also cold got my meter out and found the standard and please pay attention here the standard 7" thermostat had welded closed (just like the couple with the baby) but in this case both the top and bottom high temp cut outs tripped. So when I asked the tenant did he notice if the water was hotter the useall the last time it worked he said I have not got a clue but his girlfriend confirmed this was the case so all I had to do was replace the faulty control stat and reset both high limits where the boost started to work straight away.

The tenant said if thats the case why dont you do away with the high limits as my mum does not have this in her house I explained that the contacts welding together on the stat was a common fault plus if it happened in his mums house then her immersion could become a big kettle if she forgot to switch it off.

So as far as I am concerned I dont really care how it used to work sadly a baby has died and hopefully no other child will die as these systems get updated plus remember the couples reported the fault to the landlord plus it was looked at but the problem was not found. So think on next time you walk into a house and the couple say just make it work will you. If it was me and I found the stat to be faulty I would replace it with a combined control and high temp cut out type and I have still to be called back to a job because the high limit continues to trip.

Also just to highlight there are installations out there in the same position as the couple with the baby but by sheer luck they have the immersion on a time clock or they automatically switch it off after 2 hours of operation with the yea that water gets boiling hot if I leave it on any longer.

 

[TaffyDuck]

Well point taken, have been around the 3 I bypassed this morning and replaced them with good quality thermal trip stats.

 

[oldtimer]

Got called out this afternoon to a Cotherm immersion element and found the bottom thermostat to be burnt out plus the cover caps were removed not by the owner but the previous owner who highlighted that you sometimes have to reset the high limit boutton with the point of a pen as it can sometimes trip. Thats because Cotherm does not put temperatures on the setting dial instead they put 1-2-3-4 that equates to 0-160oC and both were set to 3 ie 120oC no wonder the HLs were tripping as they are set for 80oC.

Also does anybody know who sells these ?

 

[Marvo]

I know this is going to sound like astupid question but I'm just trying to get a clear picture of what they call an 'immersion heater' in the UK.

Are they a hot water cylinder which is pressurised by the incoming water supply or are they a gravity feed tank with a ball-float valve to fill?

Do they all have an element for heat or are some heated by a fireplace or other external heat source?

Is he water going through them heated directly by the element (or other heat source) or is there an internal heat exchanger?

 

[TaffyDuck]

Got called out this afternoon to a Cotherm immersion element and found the bottom thermostat to be burnt out plus the cover caps were removed not by the owner but the previous owner who highlighted that you sometimes have to reset the high limit boutton with the point of a pen as it can sometimes trip. Thats because Cotherm does not put temperatures on the setting dial instead they put 1-2-3-4 that equates to 0-160oC and both were set to 3 ie 120oC no wonder the HLs were tripping as they are set for 80oC.

So the danger of overheating is replaced with a danger of people standing in damp towels pressing a pen into an area with exposed live parts. Whats the chance that the Immersion cover isnt replaced ever too.

Anyone know of a cylinder stat that will take 13 amps, might do it that way from now on, dont want to have to bother with a relay.
Also does anybody know who sells these ?