Heatrae Sadia Megaflo - thermostat or element?

[matt1e]

Glad to see you got it sorted, and yes you have the older type of element
the older stats did fail often and I am convinced it is due to the way the stat plugs into the element, by use of built in female/male spades
It is a good idea to check that they are a good tight fit

there are also blue capped ones around not just white or black

as already mentioned the newer elements are a different diameter and are a different fitting type
the top and bottom elements are also different on the newer type

Matt

 

[andfinally]

Righto Tony, I'll get a proper plumber to change it for me. Cheers Matt for the help, very useful info.

 

[Agile]

Matt, do you know if the TSE is the same on these old and the new elements?

Whats the difference between the upper and lower elements apart from the part number?

 

[matt1e]

Matt, do you know if the TSE is the same on these old and the new elements?

Whats the difference between the upper and lower elements apart from the part number?

Hi tony yes they are the same physical size and spec if that's what you mean
also the TSE and TSR are the same spec but the difference is the type of sensing device in the innards, I think they are always TSR stats that they use now, but I may be wrong
regarding the elements, on the newer models that I have seen the bottom one has a 90 degree bend in it and the top one is straight, but I have seen top elements advertised with bends in them too but the bend seems smaller than the bottom one , so I'm not quite sure if its been a miss-print or that there are even newer models still that both have bends, I haven't come across one yet.
Matt

 

[Agile]

I seem to remember that there was some kind of corrosion problem as a result of stratification near the base.

Perhaps this angled element creates some thermal current and reduces that.

 

[andfinally]

Just thought I'd post an update on here for anybody else who has similar problems. The heater I moved from the bottom socket to the top worked for a few weeks, but eventually also packed up. I got 2 new heaters off eBay, and was lucky enough to find an excellent Bulgarian plumber who drained the cylinder and replaced them for me. Can't remember what he charged, it was about £80. On taking out the heaters he said they were scaled up about as much as you'd expect for their age.

Some people here warn of the potential hazards of draining ventless cylinders like the Heatrae, but it didn't actually seem so different from a normal cylinder. It might be DIYable. The plumber turned off the water supply and just siphoned it out from the bottom valve into the toilet. It took a long time to empty. Replacing the heaters was straightforward, and refilling the cylinder also seemed normal enough. The special thing about these cylinders is that they have a big diaphragm near the top which stops them completely filling up and maintains a certain level of pressure.