Worcester Bosch Highflow 440 - reliable?

[esra_ptrap]

Yes, the 440 bears little resemblence in design to the 400 and is right at the top end of storage combi's.

It's relatively new so only time will tell how it performs in the reliability stakes (as with all the latest condensers really) but a lot of thought has been given to servicing the 440 so the costs should be reasonable.

I'll let you know in 10 years

You could do a lot worse and not much better IMO

 

[Buzzark]

Thanks, that's worth some thought then.
If it's a complete re-design then it's as much chance of being reliable as A N OTHER boiler and you almost have to give it a clean sheet as previous incarnations may not have much relevance to the current product.

Much as in the same way an old style ultra reliable boiler can become a dog in it's new condensing version which only really carries the name forward..

I'm not too worried about heating as we can do without that, it's the DHW loss that always concerns me.

 

[Dan Robinson]

New desgn new problems, in the same vain that the new design eliminates old problems....

What's the name of that greek symbol of a snake eating its own tail?

 

[Buzzark]

I expect that's true of most of them. Other than it's poor efficiency, there's nothing really wrong with the Glow Worm Hideaway 70B that's currently fitted. I expect it's more cost effective in the long term to install a new boiler instead of just converting to the existing setup to fully pumped and a heatbank or unvented.

On the one hand it's not so green junking a working boiler, of the other hand a replacement is much more efficient and the savings for running it say the sooner it's done, the better..

It's a shame the manufacturers don't have showrooms where you can go and test drive the different models... I can't think of anything else that costs as much that you don't really get to see the working product before you've commited.

 

[Dan Robinson]

Very good point Buzz!

I thought you already had a Highflow fitted. If not then I would definately condsider an unvented cylinder and system boiler.

That way you get the back up of an immersion. Think again about the Multi though - we often fit them in the airing cupboard in place of the hot water cylinder.

 

[Agile]

I expect that's true of most of them. Other than it's poor efficiency, there's nothing really wrong with the Glow Worm Hideaway 70B that's currently fitted. I expect it's more cost effective in the long term to install a new boiler instead of just converting to the existing setup to fully pumped and a heatbank or unvented.

In that case you could follow my advice and fit an unvented cylinder now and a condensing boiler like a Worcester 18Ri later.

Tony

 

[Buzzark]

Yes Tony, we could certainly do it in two stages and keep them seperate.
There's room in the loft (despite the proposed conversion) for an unvented of reasonable size on the other side of a partial wall beyond where we're planning to make a room.

Sadly Dan we've no airing cupboard so the boiler would be up in the loft, not so great as we'd have to get the gas up there etc. There isn't really a place to fit the Atmos without pulling half kitchen apart...

 

[Dan Robinson]

Where is your hot water tank at the moment? System boiler and unvented is looking like the best option to me if things are as you say.

 

[Buzzark]

As it happens, it's rather conveiniently placed just the other side of that wall in the loft. It's about a 4 foot move and all the pipework is out of the way of the convertable loftspace, it doesn't get in the way.

It's probably the simplist solution if I can find an installer who'll do that and convert to fully pumped at same time or of course fit a system boiler.

From a different thread, we've got 20l/m @ 1.3bar dynamic pressure at first floor level. Is that likely to be workable as it stands?

 

[Dan Robinson]

If that is dynamic pressure then it should be OK.

 

[Buzzark]

Yes, that's dynamic.
Just replaced my 15mm stoptap on the 35mm MDPE main yesterday.
Before and after figures from my other thread:

Before the work:
14l/m at the bath tap (fastest flowing tap and closest in height to the shower)
Static pressure 2.2 bar
Dynamic pressure 0.7 bar

After the work:
20l/m at the bath tap
Static pressure 2.2 bar
Dynamic pressure 1.3 bar

Before, I don't think it was an option but now I think we're now on the lower end of worthwhile?
Not yet found out what to expect in vs out with an unvented. I assume there's some variance between makes and models in resistance? (or loss of head) Probably something for a seperate thread...

 

[gas4you]

I don't think these pressures are great enough to get the full benefit from an un-vented cylinder

 

[simond]

Me too, Dave. Can't see what an unvented will give extra when faced with 20l/m.

Other than 20l/m. A Highflow 440 will work very well within that rate. If you've ever stayed in a Center Parks chalet most of the larger 2 bathroom ones have a Highflow in them.

Try not to get one full of sludge where the rodents have knawed thru the plastic plumbing causing perpetual leakage and refilling......

 

[Buzzark]

I've never stayed at Center Parks but it sounds like a good excuse for a few days away! Actually, best save my money for the install.

I know the highflow 440 requires 1.5 dynamic pressure to deliver that 20l/m which is very favorable against their bigger combi's but I don't know how that compares against the unvented cylinders.

I also don't know if a heatbank or thermal store would work better with that sort of supply. The Range flowmax has a plated heat ex much in the same way the highflow 440 does and both are heatbanks for DHW delivery. With an unvented, are you pushing against the volume of water and losing/absorbing a significant amount of head?
Not that I can find one of those for sale mind you...
I can find the Albion but it's coil based which seems technically inferior, although less moving parts...

 

[Dan Robinson]

If going for the heatbank solution then I would stick to the Highflow.

Personally I would prefer (in your situation) an unvented cylinder.

You're half way there already and it offers several key benefits - including redundancy and moving parts. Thermal stores... Just don't seem right in this instance.