Which Unvented hot water vessel?

[Reg Man]

I am doing my homework on choosing which unvented hot water vessel to use. I know what capacity I require, its now down to choice of manufacturer. These are the following I have looked at: Fabdec Excelsior, Gledhill, Heatrae Sadia Megaflow ECO, Telford Tempest, Vaillant Unistar, Santon Premier Plus, Ariston Aquabravo. Fabdec comes out cheapest and Megaflow most expensive. The rule I normally follow is cheapest is not always best and most expensive is normally a rip off. So I thought I would put it out to you all to get your views on what you use and what you find most durable, reliable and value. Before anyone goes on about safety, G3 and you must be qualified and all that, I am qualified to work on UVHWS.

 

[Dannypipe]

Couple the cylinder with an accumalator if you have the space, rather than a break tank, and a pump.

I fit a lot of RM's cylinders. They're good value, but not nearly as nice as a Megaflow. I used to like the old style OSO's too, but they changed their designs a few years back.

I've had noise issues with the RM's. To the point that the manufacturer sent me out a new and experimental expansion vessel free of charge as nothing was wrong with my install. That solved the problem. Which was basically the opening of the expansion vessel was being restricted by the FI/22mm comp' fitting.

Oh and I've had a Mega Flow that had a failed rather nicely. I didn't fit it, but the baffle plate that forms the air gap fell to bits. It looked and felt just like Kendal Mint cake. I solved the issue of the PRV discharging by installing an 18 litre potable expansion vessel.The thing was Heatrae Sadia who make the Mega Flow didn't give a stuff when I called them. The 25 year warranty hasn't been around for 25 years, and as this unit was 10 years old, they said 'tough'.

Well the bits of the baffer plate had got into the plumbing system and ruined some extremely expensive tap/shower cartridges. I took loads of photos at the time, and posted them on here (about two years ago).

When I went on a manufacturers course at Baxi, months after this happened, they had a Megaflow, cut open so you could see inside. I've no idea why the baffle plate went soft, as I gave the one in this cylinder at Baxi a good flex, and it's tough nylon type plastic. Very odd.

 

[Dannypipe]

Found it:From 2011!!

http://www.ukplumbersforums.co.uk/plumbing-forum/20640-mega-flow-damaged-baffle.html

Here's a photo I took of the Mega Flow that was cut open.

And here is a photo of the Mega Flow I'm talking about. I removed the immersion heater and with a wet vac, sucked out the remains of the baffle plate. Like I said though, the damage had allready been done. This is a very grand house indeed. With two Megaflows, of the same age, but at different ends of the house. The other one is fine.

 

[Dannypipe]

Finally (and I know I've prattled on)

I think OSO changed their design over a patent issue, as they used to be like Megaflow with an integral air gap. Now they have two expansion vessels, at the top of the cylinder, factory fitted, and when finished, a cover goes over so they look like one unit. They also now come with a template much like you get with most boilers, but I don't fit OSO anymore, over priced in my opinion.

As you can probably tell, unvented cylinders are part of my bread & butter work!!

 

[Reg Man]

Accumalator sounds good, seen them on a few jobs, at least they do not rely on a power supply. Will upgrade the main first and test the pressure and flow, then assess if what will work. Got loads of room so an accumulator will help.

 

[Dannypipe]

Accumalator sounds good, seen them on a few jobs, at least they do not rely on a power supply. Will upgrade the main first and test the pressure and flow, then assess if what will work. Got loads of room so an accumulator will help.

Pumps are noisy too.

 

[on31ll]

More moving parts in a pump so its just somthjng to replace when it goes kaput ! Ive never seen or had a accumalator fail ? Touch wood

 

[SafeGasInstall]

u missed one Potterton gold

 

[chris watkins]

u missed one Potterton gold

Post 8, or don't I count any more, Stan ?

 

[SafeGasInstall]

Post 8, or don't I count any more, Stan ?

Chris I am sorry ! To be honest I did only read the op post 1 .

 

[chris watkins]

Chris I am sorry ! To be honest I did only read the op post 1 .

That all right, even I have stop reading some of the kr#p I type. LOL

 

[Reg Man]

That all right, even I have stop reading some of the kr#p I type. LOL

Now now Chris don't be hard on yourself.

 

[Reg Man]

Thanks everybody, you have given me lots to think about. At the moment RM Stellaflow coming up top for me, on balance of quality and value for money.

 

[SafeGasInstall]

I have fitted few 300l Main cylinders and they worked fantastic
one was on 2 shower rooms and one with shower and bath ! Only thing is customer did not want softner to be fitted

 

[neu]

Thanks everybody, you have given me lots to think about. At the moment RM Stellaflow coming up top for me, on balance of quality and value for money.

Did you settle on the RM Stellaflow in the end? We're making the same decision, same price range.


(We have a G3 engineer too, don't worry)

 

[Reg Man]

Yes RM looks good to me.

Did you settle on the RM Stellaflow in the end? We're making the same decision, same price range.


(We have a G3 engineer too, don't worry)

 

[Ted1]

OK, newbie to this forum, but this thread seems to follow closely to my requirements, so here's the situation:

House ~30 years old, small 3-bed detached, pretty good insulation & double glazing
1 bathroom with bath + shower attachment. May add shower ensuite in future,
Boiler ~6 years old, i-Ideal HE15 15kW, room sealed condensing, vented system.
Hot Water - Gravity fed system, huge cold water storage tank in loft, rubbish pressure!!!!

Thinking of exchanging regular, vented cylinder with unvented to get mains pressure cold + hot water supply throughout house. May add solar panels later.

So, attracted to Santon Premier Plus solar indirect 210ltr, but not sure whether or not to go for Megaflo equivalent?

Am I right to go for the Santon?

 

[Dannypipe]

Depends how deep your pockets are, Megaflo's are great quality in my opinion. Just more expensive.

 

[Ermintrude]

No Stanton Is rubbish. ACV out perform it all day long. Or oso or even a main it's the same but 1/3 cheaper

 

[THEJoeb]

I would look at, space ease of access and ease of connecting controls etc, if the normally fit the vaillant boiler with the rest being vaillant too, makes it easier to link everything up, I don't go for pre-plumbed.

agree cheapest is normally cheap for a reason but most expensive can be best quality a lot of the time,

 

[Worcester]

Based on the costs of install - see elsewhere, you are looking at about 2 days work, go for one of the better ones, ACV, OSO, Joule ... 90% of our installs are Joule. Great service and massive range of shapes / sizes / coil configurations to suit every need.

It will need to be installed by someone that is G3 certified, and before you decide that and unvented cylinder is the way forward you need to have the mains pressure and flows tested.

 

[Reg Man]

I did Unvented hot water under CITB first time back in 1988 and have updated this under the G3 since.

Up date on the Unvented situation is, I have put bigger mains pipe in and now have sufficient flow, but can't get the pressure up much above 1bar, so have decided not to go forward with an unvented system. Did look at break cistern and pump, but does not make much sense, as a couple of shower pumps will be sufficient for the requirements. Thank you for everyone's input.

 

[bigads28]

I've fitted and few Gledhills now and think they are good. You can have any cylinder tailor made from them which I find really handy if you are in a tight space. If you'd have asked me this question a year ago I'd have said a Megaflow but I've had quite a few now where the internal bubble won't hold its charge. Then on the other hand when an external vessel goes it makes a real mess!

 

[Ted1]

It will need to be installed by someone that is G3 certified, and before you decide that and unvented cylinder is the way forward you need to have the mains pressure and flows tested.

Cold water mains really good:
Static ~4.5bar
Dynamic ~2.7bar
Flow ~22ltrs/min

How to ensure my installer/plumber is G3 qualified?

 

[Dannypipe]

Ask to see a copy of his qualifications. Check they are in date. Then ask how the installer notifies his installations. If he is registered he will be able to tell you straight away.