Megaflo or not? - advice on install

[indianjoe]

Hi,
long story short. bought my house a couple of years ago and am now starting to save up for the big jobs that need doing. I stretched myself and bought a 5 bed but the water heating set up is just too small (house was extended from a 3-bed and even then tank is small).

Have large loft but water tank is smack bang in the middle, so would like to remove this and run everything off the mains.

Long story short I am thinking about getting a megaflo or something like this. i've been trying to do a bit of reading and did have a bit of a chat with a plumber who came round to do another job (he agreed that this was the way to go and that current standard tank is too small). There are 4 of us in the house and so am thinking that I should get a 250L tank.

All the plumbing and wiring is in an airing cupboard with some space available so I am thinking of taking out the current tank and putting an unvented system in there.

I was told that the boiler I have got is plenty powerful enough to run both central heating and tank. This is where I get a bit confused and need some advice/opinions please.

1. Advice on makes. Megaflo/ Ariston - what do the pros on here use and why? Is megaflo just a brand or is there more to it than marketing. Cannot tell when reading their site as I am not a pro.
2. new vs 2nd hand. Basically money is tight. If I can do 2nd hand I will unless there is a good reason not to.What are the watchouts? i'm assuming the age, leaks condition of coil/elements is a factor? If I sit and watch ebay - what should I ask a seller?
3. direct vs indirect. Am just confused. Is indirect powered by boiler with an immersion backup? and direct from immersions only?
Are there big differences in efficiency between the two. Is it a possibilty to just let my boiler run the central heating and have the pressurised hot water tank run from immersion only - or is that silly. Should I get an (direct?) system.
4. Control. Is it likely that I will need to have a new control module installed - am utterly clueless on this point.
5. Water softening - am thinking that this will be the final big appliance and so should prob get water softening into the property at same time - any reasons this is not a good idea?

I'm hoping that I can get a 2nd hand unvented direct system and plug it in to the existing space so I can save money on purchase, install and the running costs won;t be too high. Plus it will be independent of the central heating. So some plumbing some wiring and bobs a close relative? <fingers crossed - but I know life is never that simple>

Thanks for any pointers, would really value any opinions. Again, I have done some reading and spoken to some people and am still genuinely confused.

 

[bolshy]

Firstly, I wouldn't install a second hand unvented cylinder, and secondly, you shouldn't be installing unvented cylinders if you know as little about them as you seem to - they can be very dangerous if installed incorrectly or without functioning safety devices.
Lastly, heating water with any indirect cylinder will be cheaper than immersion heaters only, electricity is about 3 times the price of gas per kW. If your boiler is providing central heating, it's foolish not send a couple of kilowatts through a coil in your DHW cylinder.

 

[ianmcd]

Im really glad you kept your long story short

 

[indianjoe]

Thankyou.
I should have been clearer. I will be doing none of the work myself. I do the majority of small-medium jobs but know my limits and have none of the required qualifications. I think I may have some notification obligations also?

You didn't give a reason for the other advice - can you expand? Why not 2nd hand?

Any other constructive criticism gratefully received.
Any advice ian mcd?

 

[Phill Peck]

You don't want direct
I'd be very suprised if you can even find a second hand unvented cylinder
And as above unvented cylinders require a the installer to be qualified, installed badly or incorrectly can be potentially lethal.


If cost is the main issue your best bet would be to fit a bigger open vented cylinder they cost less than half that of an equivalent unvented cylinder

 

[indianjoe]

Thank you. Is the advice against direct simply down to cost?

Also I think I am using "2nd hand" to mean "little used" or "still in box" ebay things. Although there are plenty on ebay - what is the reason you advise against these?

Also as I estimate fitting to be a major operation if I have to move it I thought vented the best option as an external vent in the current location is out of the question (would have to completely relocate to loft to get this)

 

[Phill Peck]

Direct is only really for properties without gas/central heating.

If you do get 2nd hand or similar I would recommend having the inlet valve temperature and pressure relief valves replaced before fitting

 

[dcawkwell]

You don't want direct
I'd be very suprised if you can even find a second hand unvented cylinder
And as above unvented cylinders require a the installer to be qualified, installed badly or incorrectly can be potentially lethal.


If cost is the main issue your best bet would be to fit a bigger open vented cylinder they cost less than half that of an equivalent unvented cylinder

They go through regularly on ebay. Wait for one to turn up close by and have a look at it. You might even be able to see it before it gets taken out in working condition.

 

[indianjoe]

thankyou.
Also is 250 litre overkill on 5 bed with3 upstairs bathrooms?

 

[Fluffster]

I would say a 250l tank for 3 bath house is undersized as an unvented with good mains pressure and flow(something you must check before you even think of going unvented) would drain quickly if multiple outlets using at the same time.
I do not know who lives in your house, all adults baths or showers and frequency or which all should be a factor in sizing the tank.

You can position the tank anywhere in your house it does not have to be up stairs as it is mains pressured unlike the gravity/cold storage open vented cylinder arrangement. In fact better if you can put it in an insulated gargage/utility room close to the boiler on a concrete base as these monsters can weigh in at 500kg plus depending on volume when full!
If you buy new you can get a warranty for 25yrs from manufacture, if you buy s/hand no warranty and possibly a tank full of scale that has been ripped out and not decommisioned by the delicate hands of a builder
Pete

 

[indianjoe]

Thankyou.
Good point on the floor. will have to look at this.
I'm guessing first question to installer is what is the flow. Not sure about this one. I hear you on the scale etc. & warranty. I have to think about that but cash is tight also.

It is 2 adults 2 small children but they wont stay small for ever. unlikely to be more than 2 showers at same time but want to be a bit future proof. tank at is tiny! kids bath at night & 2 showers sequentially every morning.
So 300l might be best I think

am narrowing down the options - thanks guys.

 

[CBF]

you need to get your water pressure & flow tested first before you even think about this as fluff said, what is the flow per min ? what pressure have you got with 2 (mains) outlets running ? without these two answers you won't even know if unvented is gonna work, plus where ever you site the cylinder it will need a pipe going to outside or a waste pipe

 

[indianjoe]

Need to ask someone to check flow - got it. Thank you.

Still would like to know pro's opinions on the other questions I have so I know what to ask when I do get somebody in and can be keeping an eye out for the kind of things I need so I know what is a good price. If flow turns out to be a problem then I will adapt plans. If flow isn't a problem then I want to be in a position to proceed.

I figured that there would be a fair bit of plumbing to do even with keeping the location of the current small hot water tank. I thought more needed to be routed to outside with a vented so it would be more difficult - is this not right?

 

[CBF]

with a vented cylinder you don't need to route any pipes outside, but with unvented you have to run a pipe outside to low level or into a waste pipe (which could be inside) although that would have to have a constant fall

 

[indianjoe]

Great, thank you. This helps a lot.

I was more thinking about the external venting part than water pipes per se. I would prefer to locate it in an airing cupboard with no external wall so I could route water pipes out somehow - but cannot see how I would get this vented without totally relocating the system e.g. loft/garage.

So it looks like:
1. Unvented indirect in the airing cupboard, prob with mains input upgrade and replacement of safety kit / or new and careful research of who to install. Double check boiler can cope.

Or
2.vented system in garage.

Q's I'm still not sure of are. if I'm upgrading input wouldn't I may as well stick a water softener on anyway?
what brands other than megaflo are tried/tested/trusted by people on here?
If installed correctly and with safety kit replaced and annually inspected etc. are the anti unvented peopel just scaremongers?