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.

 

[Masood]

lpm= ?

Litres per minute, I'm guessing.

 

[Ray Stafford]

RM Stelflow for price and decent quality. Its our biggest seller by far - outsells Megaflo by 10:1

There are lots of different brands made in the same factory as the Megaflo - I think that the cheapest of those variants is probably Main, but watch out for price reductions - Main have just repositioned their pricing significantly below what it was just a couple of weeks ago, so make sure that your supplier knows about those reductions, and doesn't charge you last month's price.

As Vern mentioned, the Megaflo is on a £150 cashback at the moment (admission that they have hiked their price to high?) so don't forget to factor that in.

Litres per minute is probably more a function of the incoming main performance than the cylinder design, so unless its a particularly demanding spec, I am not sure I would be factoring that in.

 

[chris watkins]

RM Stelflow for price and decent quality. Its our biggest seller by far - outsells Megaflo by 10:1

There are lots of different brands made in the same factory as the Megaflo - I think that the cheapest of those variants is probably Main, but watch out for price reductions - Main have just repositioned their pricing significantly below what it was just a couple of weeks ago, so make sure that your supplier knows about those reductions, and doesn't charge you last month's price.

As Vern mentioned, the Megaflo is on a £150 cashback at the moment (admission that they have hiked their price to high?) so don't forget to factor that in.

Litres per minute is probably more a function of the incoming main performance than the cylinder design, so unless its a particularly demanding spec, I am not sure I would be factoring that in.

For the bigger installs only & as you say Ray, & only if the mains has that + pressure / flow available.

 

[Reg Man]

Litres per minute, I'm guessing.

Thanks I had a dull moment. No to honest too many whiskey's.

 

[Reg Man]

Pressure and flow could be an issue. At present it is bad. 1 Bar on a 3/4" old poly main, quite a long run and very high in relation to the water tower for Norfolk. Plan is to upgrade the main to 32mm and hopefully the resistance will be reduced and pressure increased. Fall back is to install a break cistern and pump. But don't want to do this if I can get away with it as we get a lot of power failures and this would leave us pooped.

 

[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)