Megaflo and Glow Worm - can anyone explain?

central

Hi all, I'm trying to understand my energy costs, and don't fully understand my heating system, it was installed in a new build two and a half years ago.
I have a glow worm 30 sxi boiler in the garage and a megaflo HE CL210 indirect cylinder. I have a 7 day programmer for seperate CH and HW,

When the CH is completely off (like now) does the gas boiler heat the water in the megaflo system, or does the megaflo heat the hot water electrically? I ask this as the boiler seems to be completely off with no lights or digits unless I turn the central heating on in which case it springs to life?

There are also two switches in the airing cupboard, a lower one which is connected to the bottom of the megaflo cylinder, and another with no wires, which I assume is the extra immersion heater, am I correct in thinking the lower one needs to be on and the upper one needs to be off?

Thanks for any help

central

Bumpety bump

notbritishgas

central wrote: »

Hi all, I'm trying to understand my energy costs, and don't fully understand my heating system, it was installed in a new build two and a half years ago.
I have a glow worm 30 sxi boiler in the garage and a megaflo HE CL210 indirect cylinder. I have a 7 day programmer for seperate CH and HW,

When the CH is completely off (like now) does the gas boiler heat the water in the megaflo system, or does the megaflo heat the hot water electically? I ask this as the boiler seems to be completely off with no lights or digits unless I turn the central heating on in which case it springs to life?

There are also two switches in the airing cupboard, a lower one which is connected to the bottom of the megaflo cylinder, and another with no wires, which I assume is the extra immersion heater, am I correct in thinking the lower one needs to be on and the upper one needs to be off?

Thanks for any help

Not an expert but have just googled megaflo to see what it is all about.
It seems to be just a hot water storage cylinder that comes to site pre plumbed, and works like any normal system.
It has its own immersion heater which presumably is controlled by your lower switch.
But it should also be capable of heating the water by the gas boiler. I would switch off the lower switch and set your 7 day programmer for the HW to come on, the boiler should spring to life and heat your water. there should be a thermostat somewhere on the megaflo, make sure that is set to about 65degrees.However if your water is hot from the immersion heater you may have to turn the thermostat very high to bring the boiler on, but turn it down afterwards.
If you have been heating water only by the immersion heater then that would account for quite a high electric bill.

central

Thanks for your help, I tried something today.

Hot water light on the programmer only came on, I turned off the lower switch (having already turned off the upper (what I think is the additional immersion switch) earlier in the week.

I drained all the hot water and the gas boiler didn't respond when all the hot water was gone.

Is it possible then that because the megaflo is so efficient and well insulated that it is just heated by the electric, but perhaps when the central heating is on in the winter this contributes to the heating of the hot water?

I also have just got an efergy, and the baseline went from 0.5kW to 3 kW when the hot water had gone and I had turned the lower switch on again, so I am sure the lower switch heats the water as a baseline.

Still not sure how the hot water pressure was fine when both switches were turned off to the megaflo.

dmitch071

The top switch sounds like the main isolation switch for the cental heating so that needs to be kept on at all times as sends power to boiler.

The lower switch is the immersion heater which should only really be used in an emergency such as boiler braking down and a need for hot water.

Your boiler is a A rated efficiency boiler and the megaflows are very efficient, in genral the most economical way to run this system is with hot water set on the program to 24 hrs and the boiler will just keep the hot water topped up every time the water inside the tank drops below 60 degrees or whatever it is set to.

It will be far cheaper for you to use your boiler to heat the hot water.

central

Thanks for taking an interest.

I have just turned the top switch on and turned the bottom switch off . The electric consumption on my efergy has just dipped from 3kW to 0.5kW, so the bottom switch was definitely heating the water 5 mins ago.

The hot water light has gone off, so I turned it on on the overide switch. So far the boiler has not sprung into action, and I suspect I may be in for a cold shower in the morning!

Is it possible that it has just been set up to have the bottom electric switch heat the water?

Thanks again for the interest from both of you.

I would just add, that with the top switch turned off, when I fire the central heating up, the boiler springs into action.

dmitch071

it may be that the water inside the megaflow is already hot enough so the boiler wont fire, or you have a fault with your hot water which could be why the immersion was turned on if you have just moved into the property.

I would turn the immersion of and just see if you have hot water over the next couple of days.

Or if you can find the thermostat on the megaflow turn the hot water on and turn the stat up and see if the boiler fires.

central

mmm the immersion was heating the water for a good 30mins so you could be right as to why the boiler was not firing. We've been in the house since it was bult so no faults as far as i know, only just tried to understand this. Should I turn off both switches to the megaflow and report back?

and which switch is the immersion (i suspect the lower one), if so what is the upper switch?

Thanks

Glyn

dmitch071

turn the immersion heater (lower one off) I suspect the top one is either the mains to the central heating, so if this is turned off the boiler wont fire. The easiest way to check is to turn your heating on at programmer and room thermostat up so the boiler fires up then turn the switch off and see if the boiler goes off. The other thing is it could be a fuse spur to your shower pump if you have one. more than likley the central heating/boiler isolation so must be left on for your central heating system which includes hot water to work.

notbritishgas

What dmitch has been saying is good advice and I think he may be correct with the workings of your two switches.
However one thing you do not seem to have done is locate the thermostat on your megaflo to ensure that it is turned up to a setting that will make the hot water come on from the boiler.

dmitch071

There is no adjustable thermostat that the user can adjust on the megaflow unfortunatly. I am a Central Heating Engineer so helps a bit:rotfl: