Moved into new house but advice needed please

[danie1d]

Hi,

I'd really appreciate any advice anyone can spare for me. I've read up a lot but not sure if I've actually got the final picture in my head.

We moved into a new house, well new to us. It has a Potterton Suprima 70l boiler and a Megaflo CL170. There is a programmer on the boiler and a thermostat upstairs. There is also a immersion switch.

We've come from a small flat that just had a combi boiler which was simple, when we wanted hot water it was produced etc.

What I don't understand is how this system works - that may sounds stupid but a couple of times we have run out of hot water and I wasn't sure why (apart from the fact there was no hot water left..)

My understanding is the boiler comes on at certain times and heats the water which is then stored in the megaflo, but when the megaflo is empty (that shouldn't happen too easily but has) then what happens? Can hot water not come via the boiler into the megaflo and straight out? Or if the water ran out and then the immersion in the megaflo was turned on, how quickly would the water heat?

I know the megaflo stores water and pumps it out at high pressure.

What is the best setup for this, I've not changed the programming since we moved in a figure it could do with a tweak. If the boiler was left with HW on constant what happens when the megaflo is full of hot water? Does it stop or does it continue and hot water is just wasted and pumped out of the system.

I'm not sure if I'm being clear or not so please ask questions, as I said I'd just like a bit of advice as to the best way to have this working.

Thanks and as I said any help appreciated.

 

[xr4x4]

The boiler heats a coil of water inside the megaflow, which heats up the stored water insid, this is supplied to the taps, shower or bath. This is controlled by a thermostat on the megaflow which controls the boiler. I,e when the megaflow is fully heated, the boiler stops heating the tank. If it working correctly.

I believe your hot water timer isn't on for long enough, or on at the wrong times.

The boiler will take about 20 minutes to heat the megaflow from cold.

I suggest you ethier have the hot water on permantly, or twice. 7 till 9 in the morning and 4 till 9 at night, this will depend on when you use hot water, bath shower etc.

 

[kbdiy]

The boiler heats a coil of water inside the megaflow, which heats up the stored water inside, this is supplied to the taps, shower or bath.

Not quite, as I understand it, the megaflow is a heat store. The water inside the megaflow is heated by the boiler and is also used to circulate around the rads when heating is called for. The water to the taps is mains water which is passed through a coil in the cylinder, taking heat from the surrounding water as it does so. Hence you get hot water to the taps at mains pressure.

The immersion heater is there as a backup in the event that the boiler fails or is not producing sufficient heat to cover demand.

In essence however the remainder of the advice is correct. You need your boiler on longer to ensure that the megaflow tank is fully heated so that any hot water demand is gaining sufficient heat from the surrounding water. I believe many owners of megaflows may actually have the boiler on almost constantly to ensure the heat store is always up to capacity, but as I don't actually have one myself, that may not always be the case.

Water is not pumped out of the megaflow and the stored water does not go to waste. The cylinder is very well insulated so little heat is lost during storage. The only pump you're likely to have is one which serves the central heating. The pressure at the taps is driven by the incoming cold water mains.

 

[45yearsagasman]

Not quite, as I understand it, the megaflow is a heat store. The water inside the megaflow is heated by the boiler and is also used to circulate around the rads when heating is called for. The water to the taps is mains water which is passed through a coil in the cylinder, taking heat from the surrounding water as it does so. Hence you get hot water to the taps at mains pressure.

Not quite, what you are referring to is a thermal store which the Megaflow isn't. Megaflows are mains pressure unvented storage cylinders.

 

[kbdiy]

Apologies for my confusion

 

[Agile]

To the OP.

Make sure you have your boiler heating the hot water during the time that hot water is likely to be used.

That will enable the water to be reheated as its being used.

A Sup 70 will in effect provide about 7 litres per minute of reheated hot water.

You dont say how any people live there but a 170 li is really only suitable for two people who are relatively conservative with HW useage.

Tony

 

[danie1d]

Thank you all for your feedback - it is as I thought. I'm going to play with the settings and see how we do.

Will it definitely stop heating the water once its full or am I going to kill my gas charges by leaving the water on constant?

It is just two of us so the water should be ok.

Thanks again.