Fortic tank (combination cylinder)

[dsteves619]

Recently come across what is becoming a seriously problematic Fortic Tank( I`m sure they do go by different names but at this moment just cannot remember)
The cylinder is situated in a loft space, it is fed directly.
Sometime last year their hot water stopped working so I changed the thermostat in the immersion heater and job done.
About a year later the guy calls me back as he has water coming through the ceiling. I check the cylinder and notice the water in the header tank is warm, so I automatically assume the thermostat has gone again and it has boiled over. ( For some reason the installer has sited the overflow higher than the cold feed..... muppet).
So I change the thermostat. When I turn the water back on I notice the ball valve is letting bye, so I go ahead and change that.
I pressume over the years this has happened before as there was staining to the ceiling, and two trays under the cylinder, probably put there to catch water.
Anyway fast forward four months and the thing boils over again, this time taking part of the ceiling with it.
So the customer, probably at this point thinking i`m pretty incompetent, rings his house insurance guys(usually he rings me if he has any probs) and their task was to stop the leaking.
For some reason the guy changed the ball valve(????????), the one I had changed a few months earlier, why the customer did`nt tell him this I don`t know!
The guy also advised that there could be a split in the cylinder and to keep an eye on it.
Now I am sure that this problem is gonna happen again, obviously the positioning of the overflow needs sorting.
But I now see myself with only two options........ change the immersion heater or completely change the cylinder alltogether as its just becoming problematic.
I have just googled internal diagrams of combination cylinders and can now see that the guy could only be right about the cylinder splitting if it was an indirect cylinder.
TBH I don`t deal with this type of cylinder too often so perhaps some of you knowledgeable heads could fill me in with some help and advice.

P.S the electrics at his place are quite old and sometimes his lights pop out every now and again. probably irrelevant.

 

[mikegas]

Is it not a thermal store?

 

[Mike Jackson]

It's not possible for an immersion heater to boil over if you are using a thermostat with an over heat cut out, which you should be to comply with modern regulations.

 

[tamz]

The water in the top part of a fortic (combination cylinder) will always heat as there is nothing to insulate it from the water below.
Fit a new overflow, preferably in 32mm in the right position and blank the old one. Make sure it is properly sealed.
Immersion should have a thermal cut off that will prevent the thing boiling (if it ever was).

 

[dsteves619]

Mikegas, its basically a normal cylinder but has a header tank built into the top of it.
And MJ, I bought the thermostat from Wickes a few months back, so I would guess it would comply with regs.
Perhaps the immersion heater is faulty.
Why the guy changed the ball valve, I don`t know. Surely he could see it was more or less brand new.

 

[mikegas]

Mikegas, its basically a normal cylinder but has a header tank built into the top of it.
And MJ, I bought the thermostat from Wickes a few months back, so I would guess it would comply with regs.
Perhaps the immersion heater is faulty.
Why the guy changed the ball valve, I don`t know. Surely he could see it was more or less brand new.

I know but they do fortic thermal stores aswell, I was asking because these have a coil at mains pressure

 

[Mike Jackson]

And MJ, I bought the thermostat from Wickes a few months back, so I would guess it would comply with regs.

Unfortunately there are immersions that have the cut out separate to the stat so you can't assume anything complies. It's also not necessarily illegal to sell stuff that it's not legal to fit.

 

[dsteves619]

I don`t think it has Mikegas.
There is no GFCH in the property which I would pressume it needed if was the case.
And MJ, you could be onto something as I took the thermostat out of a new immersion heater and put it into the old IH.
Tamz what you said made alot of sense but I would`nt need to seal the old overflow as the water would hit the cold inlet before the old overflow hole.
( sorry mate just being pedantic, would only take a couple of mins to rectify,lol.) You don`t think 22 plastic is adequate then?

 

[mikegas]

I don`t think it has Mikegas.
There is no GFCH in the property which I would pressume it needed if was the case.
And MJ, you could be onto something as I took the thermostat out of a new immersion heater and put it into the old IH.
Tamz what you said made alot of sense but I would`nt need to seal the old overflow as the water would hit the cold inlet before the old overflow hole.
( sorry mate just being pedantic, would only take a couple of mins to rectify,lol.) You don`t think 22 plastic is adequate then?

No the coil is the cold main which comes out hot, not another heat source

 

[tamz]

Things are done differently in England but a 22mm or 3/4" will never be adequate as an overflow. It is only a warning pipe.
Remember to allow for expansion of the water as it heats. 140 l of water will expand by almost 1.5 l volume @ 50º⌂T

 

[dsteves619]

The thing is it only seems to be boiling over once every few months.
With the overflow set up correctly, there won`t be any water coming through the guy`s ceiling, and I won`t need to replace the fortic for a new one.
The hot water is working fine.