Megaflo Mk 3 Immersion thermal cutout

Can anyone identify the name to describe the 80 degree thermal cutout that is fitted within the immersion heater that is fitted in a Mk 3 Megaflo.

Also, does it come out wet or dry - is there water pressure behind it or does it sense temperature through metal...Do I need to drain the cylinder to just change the cutout ?

Wakey wakey knowledgeable people... someone must know this one. I suspect it's the thermal cutout " red spot" or thermal cutout "blue spot" , although I can't see the spot as the old one's disintegrated!

YOU need some one who is qualified to play with safty devices on unvented systems

IE: G3 ticket. assuming u havent from asking such a basic question.

Don't start! It's not a technically basic question, just trying to identify the right part. The existing 80 degree thermal cutout that is incorporated within the immersion heater body is open circuit because it has disintegrated - it is 17 years old. I am going to replace the faulty part. G3 or not. I could always go and do a G3 course for the same price a G3 chap would charge to visit! If i decide to fit a new cylinder i might well go and do G3 just to keep the LABC happy, but there is no question of what is the fault. i am not going to even consider bypassing this safety device. It looks like there has been gradual chronic deteriation of the plastic housing of the cutout. It has not failed due to any problem of the system / installation.

Hi

This web site might help you identify the part.
http://85.189.44.185/Baxi/System/DATA/Dx/DS1/installation/2978/I48-2978/I48-2978.htm#f2

PRS1 is dead right you need to have G3 ticket.

Thanks... The issue is distinguishing to a parts supplier the difference between the manual reset thermal cutout in the electric immersion heater from the thermal cutout mounted on the primary circuit pipe. Trying to avoid forking out for a whole new immersion element as these are £120, a bit steep considering that a 'normal' one is a tenner!

Regarding the G3 issue - yes, undertood - I was already aware of the regs, although to replace a faulty part that comes out with a few turns of a spanner, is not a safety issue as long as I understand well the way the system works and all the safety devices.

In fact, the cylinder was originally fitted by a G3 bloke for the house's previous owners, and LABC was notified, yet it seems that the expansion relief valve was originally absent from the installation!!! I have since fitted one in addition to the pressure reducing valve (and the T & P safety valve) that were already there.

So sod the G3 people - they installed the Megaflo and left it since new in a much more dangerous state than I have since tinkering with it and bringing it up to MI standards, even though I am not a G3 bloke.

This part is one of a few critical safety parts that keep the cylinder from becoming a major accident.
If as your post sugests intend to fit this part yourself at least have the megaflo checked over by a g3 ticket afterwards.

What will they do? Leave it any safer than the last G3 bloke who looked at it??!!

Presumably the only way to check the correct operation of the new cutout will be to ramp up the immersion stat setting to 90 degrees and check that the cutout - cuts out!

I have already fitted a pressure guage on the cylinder inlet pipework. There is even an additional expansion vessel fitted to it providing extra expansion relief in addition to the internal air gap, which is not so reliable on a lot of Megaflo units.

I shall be encasing the unit with 200mm thick hardened steel and digging a large trench / pit filled with sand around it with a circumference of 25m. I have evacuated the local Parish and cut off all gas, water and electric supplies to NW London.

Internet connection still working, though.

Anyway - the G3 course is only a day, much of which do doubt taken up with tea breaks, lunch, crap dirty jokes told by a tired retired plumber working in an industrial estate posing as a training centre...