Megaflo or OSO cylinder

[clanger]

I'm putting an unvented cylinder into my house. I've had prices for both Megaflo and OSO cylinders. I know that Megaflo are pretty good, but does anybody know about OSO cylinders? Are they worth going with?

[Neil Jones]

I looked at both these cylinders. The OSO reduces the pressure to 2.1 bar, I think, against 3 or 3.5 bar for the Megaflo. They are both stainless steel, and I think they both use the internal air bubble technique to manage water expansion.

They are both reputable cylinders, but I have ordered a Pandora heat bank from dps instead.

Regards

Neil

[John Horne]

I have a 210L Megaflo, I've had it 2 years now and it is excellent, lashings of hot water and I have 9 radiators+ 2 towel rails. My local plumbing merchant said it could be used for a "rugby changing room" or a "small guesthouse".......!! We have neither nevertheless I am very impressed.

[Aenuff]

Just (10 days ago) installed a 210l OSO indirect cylinder and so far very impressed. Took about day to install including making up a base although I had a 30amp supply and a cold 22mm feed straight of the main already in place by sheer luck.

I went with the OSO as it was about £50 cheaper than the megaflo and was in stock. I was intially after a direct unit but the indirect gives me more options later and it seems to recover quick enough as its only driving 4 showers and gives excellent pressure even when you run all 4 full pelt.

IME does what it says on the tin, easy and quick to install with a few lengths of copper and a couple of big wrenches. Plus OSO tech support was superb before the purchase.

Tony

[clanger]

Thanks for the replies guys. Well the company who originally gave me a guide price of £1300 to install an OSO has now come back with quotes of £2199 for a 250ltr Megaflo and £1999 for an OSO cylinder....both plus VAT. Quite a price difference. They said the price change was due to it not being a 'straight' swopover job - even though when they where here they said it would be done in a day. They did quote £1190

• VAT for the cylinder, even though I can get it for £770 + VAT. I think they decided to alter the price a bit having taken other things into consideration.

Lucckily a chap I know has done quite a few unvented installations and he's happy for my business to buy the parts (so I can get the VAT back) and he'll come and install it next week.

I've decided to go with the megaflo because 1) the installer is very familiar with them and b) I fancy the idea of 3bar over 2.1 bar.

[Christian McArdle]

Ouch. That's around 1400 + VAT for a day's work. I'm in the wrong business. Assuming it takes them 10 man hours, that's 140 pounds per hour. Better than minimum wage. If they get it done in under five hours (more likely, unless there are long pipe runs to install) its more like 300 pounds an hour.

Christian.

[Aenuff]

If you can get someone to install at a reasonable price all the better. I paid £650+vat for a 210l OSO so price on a 250l Megaflo probably isn't miles off but check the actual capacity. When I looked at Megaflos the 300l was only about 270?l capacity.

As a side note the OSO pressure valve can be "upgraded" by replacing a "part" to vary the pressure between 2.1 and 3 bar (possibly a bit more I think).

ATEOTD I don't think there much between the Megaflo and the OSO, at least not on paper.

Good luck

Tony

[The Natural Philosopher]

It IS a biggish job, installing an OSO. Mine was 600 plus vat I think. The plumbers took about three days with one and a bit working on it, for the cylinder alone, plus there was a fair bit of pipework, and construction needed to support it in the loft, not to mention actually getting it up there, plus electrical work on the valves and stats.

When you go from gravity to mains pressure, you need to a in safety pipework, get it venting to a safe place, upgrade a lot of 15mm to 22mm, and sometimes double up to be able to take advantage of the higher potential flow rates.

Agreed that its not a grands worth of WORK, but its a lot of hassle, and faffing around, and bits and pieces.

[Aenuff]

I really did do mine in a day (with a long lunch!). But, I have a proper staircase to the area it was sited in, I wasn't working in a loft and probably more importantly I had a 30amp feed less than a metre away along with a 22mm cold feed.

With the OSO *everything* comes in the box except for the copper and the 6-8 elbows needed. It even has a flexi with it to make positioning the pressure reducer/relief easy.

I'm really no plumber but it is just basic pipework as long as your existing plumbing is up to the job. The only bit that isn't DIY is signing the cert for the BCO but the instructions even give you the calcs for the vent pipe length dependant on the pipe run and no. of bends. So as long as you can read its pretty straight forward.

[The Natural Philosopher]

It must be, since the plumber who installed mine was of the uncivilised gibbon variety.

A lot of what he did was invloved in getting the pipes to it, as much as anything else.