Fortic Combination Tank

[JessUK98]

I have what I think is an electric Fortic vented combination tank. Basically cold water header tank is built in with hot water heated directly in the tank below. No radiators or other type of boiler connected.
Looks similar to the one shown here;
http://www.gasapplianceguide.co.uk/Newa ... inders.htm


What would be a decent alternative to this? Would this: https://www.buildingservicesindex.co.uk ... cylinders/ or this: https://www.buildingservicesindex.co.uk ... e-heaters/ be suitable?
Mine overflow pipe is constantly dripping and it is also over heating the water (doesn't matter what temperature you select it comes out intolerably hot). I've had the float arm replaced as the overflow was dripping previously (about 2 years ago). I think I'd rather just replace it with a new foam insulated one.

I also currently have it wired into a manual timer. I'd like to replace this timer with a more modern programmable one if possible, I was thinking something like this:
https://www.screwfix.com/p/lap-7-day-di ... imer/1804r

Also would it just be a case of draining this system, removing the tank and then just popping the new one in? I'm wondering if I should have a crack at it myself or find a plumber (an impossible feat it seems at the moment).

TIA,
Jess

[SteelCamel]

If you want to do a like for like swap, your only option is another combination cylinder. They are available pre-insulated, like the examples you've linked to. The difficulty is that the connections may not be in the same position on the new tank as they were on the old, so you may have to modify the pipework. Still, with an electric one there are only three connections to make (cold in, hot out and overflow).

However, neither of the problems you describe are due to the tank itself. Overheating the water is probably due to a faulty thermostat. You may be able to remove and replace the thermostat from the immersion heater, if that's not possible you can replace the whole heater. You'll need to drain down but there's no need to disconnect any pipes. Note that there should be a drain point at the bottom of the tank - you can't empty the tank by turning the tap on.

Overflowing is down to the float valve (unless the hot water is boiling and pushing back into the cold tank - this is dangerous and needs fixing urgently).
The water level should be well below the overflow, at least a couple of inches. If it's too high, adjust the float valve lower. If the float valve won't shut off, replace it - turn the cold water off, and then it's just two nuts to undo to get it out. You don't need to drain the tank, though it will be easier if you run off some water to lower the level in the cold tank.

The timer you've linked should be fine for this system, either the old or new versions.

[jfgw]

Overheating the water is probably due to a faulty thermostat. You may be able to remove and replace the thermostat from the immersion heater, if that's not possible you can replace the whole heater. You'll need to drain down but there's no need to disconnect any pipes.

To clarify, you do not need to drain down to replace the thermostat. Just take off the cover of the immersion heater (isolate the power first, obviously), disconnect the old one, pull it out, put a new one in and connect it up. As long as access is easy, this should only take a few minutes. If there is any water behind the cover of the immersion heater, it leaks and it should be replaced.

To replace the immersion heater, you will need to drain the cylinder down completely. Opening the hot taps will not drain the hot part of the cylinder as the water is taken from the top. There should be a drain-off cock on the pipework at the bottom - good luck with that! Have a replacement washer handy as you may need it (replace it anyway). Have plenty of towels and fix the hose with a hose clip if it is not a tight fit. You may have to unscrew the drain cock a long way before anything happens as sometimes the washer sticks in. Expect it to dribble - this is normal, hence the towels. An old cylinder may split when you try to unscrew the immersion heater so allow for that in your budget.

Above all, have fun!

Cheers,

Julian F. G. W.

[JessUK98]

Thanks for the replies, all very helpful.
I’ve done some investigation work today and as suspected, it is the float valve (again!). Took lid off top and water was halfway over the overflow. Taken some water out to about an inch below that and the valve has a slow drip. So I’m guessing over time that drip has raised the water to the point it overflows. Is it easier to replace the entire arm, or just take it apart and change washers etc?
I’m not too fussed about the water temp at the moment as I only heat the water for an hour in the morning, and an hour in the evening and the water cools enough over the day to use for washing hands etc.

I’m definitely going to replace the whole tank when I’m feeling brave enough. The header tank has a load of yukky crap at the bottom, and I think it’s starting to get too unreliable. Looks like at some point there has been a few drips from the immersion heater part. The drain valve looks like it will not play nicely as well.

[JessUK98]

Changed to float valve today. I had a part 1, so I put a part 2 on. So far so good. I’ve set the water level to about 50mm below the overflow.
Also put the programmable timer on while I was at it. Need to leave it 14 hours to charge the internal battery before I set any programmes according to the instructions. The power light is on, so I know it’s working at least.

[vrmk]

My Fortic Combination Cylinder is several years old. The top header tank had a sacrificial element that calcium was deposited on. It has now disintegrated having been consumed by the limescale attached to it. I imagine it is acting as a water softener. It is heated primarily by a oil fired Rayburn and also an internal immersion heater on overnight cheap rate Economy 7.

Question. Can one replace it. If so by what and where can you locate the same