Heatre Sadia Mega Flo question

[AlanB27]

Hi Everyone,

Ok before I begin, im only 27 and my wife and I have just bought a new house and I have no idea about different central heating systems!

Ok, so heres my problem, basically the house we have bought has a 2 year old boiler/oil tank and radiators throughout the house for the heating which is great. There is a hot water tank called a Heatrae Sadia Mega Flo in one of the cupboards but what i dont get is, is this thing worked off the boiler, or does it work independantly?

I notice in the kitchen there is a little white control panel with settings on one side with a radiator symbol and the other side has a tap, so im wondering is that where we regualte the hot water from, or is that only if you use the boiler to heat the water

I think you can start to see my confusion lol.

I looked at the Heatrae Sadia website, but didnt really understand much of it

Any help suggestions info greatly appreciated

Thanks in advance for your help guys

Alan

 

[gas4you]

Megaflo is an un-vented mains pressure fed hot water cylinder. In your case the water will be heated by the boiler, tap symbol on the programmer, your rads will be heated by the boiler also, rad symbol on programmer. Set what times you want for each on the programmer. Although not strictly necessary I always recommend to my customers to set the hw time to come on about 30mins before the rads in the morning so you get the full power of the boiler heating the megaflo on its own. Then when the rads kick in you will be getting the full power of boiler to heat heating.

If in the unlikely event that you get a boiler breakdown you can heat the hot water in the megaflo via the built in immersion heater.

 

[Agile]

Make sure the immersion heater is off unless you dont want to use the boiler for some reason.

Tony

 

[AlanB27]

Ah right I see, so the Mega Flo could be used by someone who had say electric storage heating, to heat their water using the immersion, whereas in my siutation the boiler heats the water in the mega flo and then u specify where it goes via the control panel (rads or taps)

That right?

Other thing i wasnt sure about, the Mega Flo has a small piece of silver braided type flexi pipe with a valve at each side and a pressure guage. For some reason both valves are in off position, why would this be? Could it not just be left on all the time, or do you manually switch the water on and off. Theres not been anyone in the house for a month or 2, which could also explain it

Thanks

 

[ChrisR]

Could it not just be left on all the time

NO!
You will have a "sealed system" central heating. I.e no gravity feed from a tank in the loft like your mum had. There should be a pressure gauge, probably near a red round expansion/pressure vessel, and a valve with a red knob (don't touch). Gauge should read about 1 bar normally. If it drops you open the two taps on the braided Filing Loop to put the pressure back to 1 then turn them both off, or to be correct, disconnect one end.

You would normally us the boiler to heat your water as it'll be cheaper and much faster than the electric immersion heater, which is really only for when the boiler packs up.

 

[AlanB27]

Could it not just be left on all the time

NO!
You will have a "sealed system" central heating. I.e no gravity feed from a tank in the loft like your mum had. There should be a pressure gauge, probably near a red round expansion/pressure vessel, and a valve with a red knob (don't touch). Gauge should read about 1 bar normally. If it drops you open the two taps on the braided Filing Loop to put the pressure back to 1 then turn them both off, or to be correct, disconnect one end.

You would normally us the boiler to heat your water as it'll be cheaper and much faster than the electric immersion heater, which is really only for when the boiler packs up.

Ah right, that explains a lot. I couldnt understand why the 2 valves would be off, and also what the point of the gauge was. So basically the only time u need to open that valves is as u say if the pressure in the system drops for whatever reason below 1.

Thats brilliant, thank you very much. Really starting to understand this new world of houses and their workings lol

 

[gas4you]

Ah right I see, so the Mega Flo could be used by someone who had say electric storage heating, to heat their water using the immersion, whereas in my siutation the boiler heats the water in the mega flo and then u specify where it goes via the control panel (rads or taps)Thanks

Yours ia an 'indirect' megaflo, someone with storage heaters will have a'direct' megaflo. The water in your megaflo is only your hot tap water. It does not go around the radiators depending upon the control setting.

The programmer and thermostats tell the heating system water 'which way to go' via electric zone valves, probably 2 silver boxes near the megaflo, the hot tap wter is heated in the megaflo via a coil inside it that the heating water passes through. They never mix! This coil heats it the same way as the back up immersion heater does

 

[ro53ben]

Apologies for the thread bump, but it seemed sensible as I have an identical or at least similar system.

My MEGAflo install can be seen in the linked picture:

http://www.pbase.com/jaffacake/image/61080361

We moved in during the early summer 2006 and the hot water worked just fine. In the winter, we turned the heating on and that worked perfectly too.

All good so far.

One day I noticed a lot of air in the radiators, they were all cold at the top so I bled them. Lots of air came out and the upper section warmed as expected. I bled them until water squirted out.

Shortly after, we noticed it was getting cold in the house. Heating was still on, so I checked the boiler. It had an error indicating that there wasn't enough pressure in the system. I checked and it was below the minimum 0.5 bar.

A check of the installer manuals told me that the system needed to be pressured up and I found the tap on the silver flexi hose and opened it up. As soon as pressure was above the minimum, the heating kicked in and all was fine.

Since then, even without the need to bleed the rads, the pressure seems to drop randomly. Last night it was clearly around 1.5bar before I went to bed at 11pm. When I got up at 6am, there was no pressure at all. A significant loss. At other times it has run for weeks, even months, without issue.

During the summer, when the heating is off, we have no pressure issue at all - only when the central heating is on. If I charge a cold system to 1.0bar and then turn on the heating, I find that the pressure will initially drop a little and then build up significantly as the water warms, then drop again. It bounces up and down a little. Every time the heating click on/off with the thermostat, the pressure changes.

So we've got by until now just by topping up the pressure as necessary.

Last Autumn, the boiler tripped out whilst I had a visitor. He is a water engineer and suggest that we bleed a couple of valves in the airing cupboard. These are the thumb valves on the copper pipes that stick in the air on the left hand side of the picture. After he did that, and we re-pressured, the system ran just fine for 3 or 4 months without any issue at all. Then it tripped again. I found more air under these screws and released it. It lasted a few more weeks, then tripped again.

Now we're back to almost daily pressure loss again. I have no idea why and wondered if there was any obvious reason for this, before I call in an expert. There's an installer sticker on the system and I guess I'll call them if I need to.

Obviously we have a workaround for now that helps us re-pressure the system and get the heating back on, I'm just wondering if there's any way to keep this pressure there and where it might be going.

Thanks in advance for any responses.

Cheers,

Ben,

 

[gas4you]

Check the prv pipe off the boiler for dripping/leaking.

Check the system for leaks, i.e are there any new damp patches on the floors or ceilings?

Look in FAQ's for how to check the expansion vessel on the boiler, or the red 'ball' looking expansion vessel if you do not have a system boiler.

 

[ro53ben]

Expansion vessel? It's a MEGAflow, I don't believe there is one.

No apparent leaks or overflow.

 

[gas4you]

If the boiler/heating is cutting out due to low pressure, then it is nothing to do with the megaflo pressure.

What boiler do you have?

The expansion vessel I am referring to is the heating system one. Either built in the boiler, or seperate.

 

[ro53ben]

OK, thanks.

Boiler is a Potterton Promax System 24 HE Plus.

 

[gas4you]

In that case the EV is built in the boiler. Get the MI's out and follow the FAQ's on here to check the EV if you are certain you have no leaks on the heating system anywhere.

 

[ro53ben]

Thanks for your help, I think it's time to call the phone number of the installer.

 

[fdimu]

How did you fix it?