Less hot water than usual

[Danm54]

That's odd, all of the megaflow systems I have installed for the last 10years have been gas boiler fed...

I have to agree with @Countcussy that your wording wasn't the clearest.
Whilst the cylinder is fed from the boiler heat wise, your post makes it sound like the water flowing through the boiler feeds directly to the taps. And should the boiler not be on, then it's fed from the cold main.

I understand what you're trying to say as I've been a plumber for 16 years, but to anyone that doesn't already have knowledge how the system works it can come across very different.

Edit, rereading your post you do say that the boiler refills the cylinder which isn't correct.
The cylinder is always fed from the cold main, the boiler simply heats the water in the cylinder as it cools down.

 

[psd99]

That should be plenty, even at this time of year.

Possible simple scenarios:
Someone has turned thermostat down on the Megaflow.
Thermostat faulty, or turning off too soon.
Boiler turned down or set to eco mode, possibly after a service. (Speaking from experience)

I can`t think of anything else. Well, I can, but would probably require a visit from a plumber.

As for having on 24/7, that will be fine. I don`t think its the final solution, as something has clearly changed, but the boiler will only run when the thermostat tells it that the water in the tank has cooled enough to require heating.

Let me know the outcome. I am intrigued.

thanks yep set it 24/7 for now

I think it might be a faulty thermostat personally or there is talk online about sediment buildup impacting the amount of water in the tank that can be used for hot water.

but cba to spend extra money this time of year with xmas coming up

 

[BigBoy]

I have to agree with @Countcussy that your wording wasn't the clearest.
Whilst the cylinder is fed from the boiler heat wise, your post makes it sound like the water flowing through the boiler feeds directly to the taps. And should the boiler not be on, then it's fed from the cold main.

I understand what you're trying to say as I've been a plumber for 16 years, but to anyone that doesn't already have knowledge how the system works it can come across very different.

Edit, rereading your post you do say that the boiler refills the cylinder which isn't correct.
The cylinder is always fed from the cold main, the boiler simply heats the water in the cylinder as it cools down.

Absolutely, I was trying to make it as simple as possible for someone who knows very little as to the inner workings of a megaflow

 

[Countcussy]

thanks yep set it 24/7 for now

I think it might be a faulty thermostat personally or there is talk online about sediment buildup impacting the amount of water in the tank that can be used for hot water.

but cba to spend extra money this time of year with xmas coming up

You would have to have one hell of sediment build up

Although, I have seen build up in the coil/pipework that goes through the megaflow. This reduces the efficiency of the system, and means the water is heated slower. Extreme instances can result in the boiler cycling on and off, because it simply can't move the water through the megaflow fast enough. Keep us informed.

 

[psd99]

So if its a 250litre tank
How much of the 250 is actually usable?

would it be roughly 33%less or the full amount?