advice on changing a thermostat please

[dacker]

Hi
Do i have to drain the water from the cylinder when i replace the immersion heater thermostat?

Water is flowing out now and again from my friends house top overflow pipe and he has asked for my help, i have only just passed my level 2 so i am still inexperienced to be honest, but i will check the loft cistern float valve first and if thats ok then i think it is probably the cylinder immersion heater thermostat, i am only guessing because the water is not flowing out all the time. So i am assuming that the cylinder is boiling up and sending unwanted hot water up the vent pipe into the loft cistern and out through the overflow pipe.

Is this the correct procedure for fitting a new stat
1, isolate Ih electric supply at consumer unit and also use tester to make sure no current at Ih (to make sure! )
2, remove top small nut and remove top/ cover
3, free the two wires by undoing two screws in stat and remove stat
4, fit the same type new stat and reverse the above

But would any water spill out when i remove the stat?
Do i need to drain water out of the cylinder or would it just be a small amount of water?

I would really appreciate any advice, i could well be diagnosing it wrong
many thanks

 

[Puddle]

you do not have to drain to replace a immersion heater thermostat

Also you should not be using a 'tester',you should be using a multi meter,there is not reason to have the power supply on when testing the unit ,as is the case when testing many items correctly with a multi meter
maybe a electrical course could be looked at

As for diagnosis get yourself to job and check, over the phone comes with experience and still you can get wrong
Visit job, take your time, check out all possibilities and go from there

 

[tamz]

If house has no heating, the ballcock needs a washer.
Absolutely nothing to do with the immersion heater, unless it is a coal one Think about it.



If the stat was faulty it would not be an intermittant fault, when it is gone it's gone.
I think your mate would have noticed the cylinder doing a bit of rumbling and the water also being so hot at the taps the steam would be coming out.

Your procedure for changing a stat is correct except for 4.
Fit same length stat but one with a manually reset thermal cut out.
You don't need to drain the cylinder to change one. It is in a dry pocket.

 

[joe brown]

If house has no heating, the ballcock needs a washer.
Absolutely nothing to do with the immersion heater, unless it is a coal one Think about it.



.

who mentions the house has no heating?, If the house didnt have heating they would of noticed this before they noticed the overflow unless they havent had the heating or hotwater on because of the hot weather we have witnessed.

If a stat goes on an electric emersion heater then this will definetly cause water to spill out the overflow !!

 

[dacker]

Hi Puddle and Tamz

Thank you very much for your kind advice, i really appreciate your time, i have not got the full details yet, but i think he has got hot water and the heating is ok, i am going to have a look at it on monday for him.

As a general scenario, for any future jobs where water is intermittently pouring out of the overflow pipe, what would a plumbers diagnostic steps be?
I am very inexperienced so i have probably not got a clue, but there must be something thats points to a solution.
Regarding my friends house, if the loft cistern float valve is ok then maybe its water coming up from the cylinder vent pipe so what would cause water to intermittently flow up the vent pipe?

many thanks

 

[dontknowitall]

Might not be the immersion heater at all!! For example if it's dripping when they return from work and then doesn't drip again until the morning and not over the weekends then it could just be a drip every so often through the inlet valve from the mains. Not dripping at other times because enough water is being used to keep it from over flowing.

If it is the immersion heater it might be just the heater part or it could be the whole element that needs changing.

 

[dacker]

Hi
many thanks to all of you

My friend says the water does not pour out of the overflow all the time, but when it does, it absolutely pours out

thanks

 

[Toddyplumb]

Ball valve sticking down ? You r gonna have to have a look. Start up top !

 

[joe brown]

Hi
many thanks to all of you

My friend says the water does not pour out of the overflow all the time, but when it does, it absolutely pours out

thanks

where did you do your training mate

 

[tamz]

who mentions the house has no heating?, As in heating system If the house didnt have heating they would of noticed this before they noticed the overflow lack of radiators or other heat emmiters would give this away unless they havent had the heating or hotwater on because of the hot weather we have witnessed. Why would they be using the immersion if they had a heating / hot water system and how would this relate to an immersion The way the op worded the post suggested a direct hot water system

If a stat goes on an electric emersion heater then this will definetly cause water to spill out the overflow !!

This is true but it will not cause the overflow to run intermittently every other day. When a stat is goosed it don't start working again

where did you do your training mate

Where ever it was, as with all this fast track stuff it seems it was certainly worth the money

 

[dacker]

Hi

many thanks for your kind replies, this really is a great forum with lots of knowledgeable people.

I passed my level 2 at Salford college Manchester, sept 09 to june 10. I really enjoyed it, great tutor and people in the class.
I now need the NVQ to compliment it so i have got to find a local plumbing company that will take me on, i will work and labour for free, but it will be worth it to gain valuable experience and also achieve my NVQ qualification.

I am going to investigate the leaking overflow problem on monday and hopefully repair it for my friend.

many thanks