Boiler Replacement

[Luis21x]

Hi,
We are in the process of replacing a Range Powermax boiler for a new unit. We have good mains pressure on the cold incoming, and the Powermax currently operates a shower directly very well.

We have been recommended either a Vaillant 831 Eco Combi or a Worcester 30CDi.

We have a 2 bed semi with one bathroom. I can't find the HW ouput rate for the Powermax, but the Vaillant is 12.7 l/m. Will the recommended boilers perform better than the Powermax, and be more than sufficient for our needs ?

Regards,

 

[petit_pablo]

Depends what powermax model you have but the hw flow rate varies from 12l/m - 18l/m.

To be fair i would be surprised if you have much more than 13l/m on your incoming mains so either of the combi's you mention would be sufficient for a 2 bed semi.

 

[Luis21x]

Thanks for the reply.

We have a Range Powermax 185 boiler, which has an F&E tank in the loft.

The suggestion has been to replace this unit with either of the previously mentioned combi's which I believe are fully sealed systems, so the F&E tank will become redundant.

I'm unsure if we would get an equal performance from the new boiler in terms of hot water delivery ?


Regards,

 

[Luis21x]

By the way the reason we are replacing the Powermax is because it constantly leaks, and it's impossible to get anyone to repair / service it.

We also have small microbore pipework, is there a high chance of getting potential leaks in the pipework when introducing a sealed system which must be under more pressure than it is currently.

 

[Terry lambert]

The Vaillant 831 will actually give you about 10 - 10.5 litres a minute once it has been heated to a usable temperature.

You could vet your engineer to speak to the different manufactures to get their flow rates at the higher temperature rise of, I think 42 degrees or their abouts

The 12.7 ltr min. Quoted by the manufacture is at a 35 degree temperature rise which is how manufactures state their flow rates. Which is too cool for normal use.

You could get your engineer to show you what the different flow rates look like with a flow cup.

Their is always a chance of leaks going from low to high pressure, their are things your engineer can do to minimise this if your pipework is obviously poor and likely to leak.

 

[Dan Robinson]

install an Atmos InterCombi HE32 and you can keep the heating open vented and minimize the chance of leaks in your microbore.

 

[Luis21x]

Thanks for all the replies.

Dan,
I've never come across the Atmos boiler. Does it compare well to the Vaillant, technically and economically ?

I've been quoted £1700 to supply & install the Vaillant 831 boiler including power flush.


Regards,

 

[Dan Robinson]

A fraction more expensive to supply, but vastly different in terms of operation. Only 4 moving parts, not separate heat exchanger for hot water.

Can be run without the heating connected if there is a problem. Pretty much all we have been fitting since 2004. Very few problems.

 

[mickyg]

before you accept anything I would get your current hot water output measured. Powermaxs can have a very high performance hot water output, and you may be very disappointed when you switch.

 

[Luis21x]

Thanks Dan / Mickyg for the replies.

I will get the output measured. That has been my concern regarding the hot water output as we do get an excellent supply with the Powermax, it's a shame no one is prepared to work on them !!!

Of the three quotes I've had they all recommend the Vaillant 831 or Worcester models, which will do away with the F&E tank.

It's difficult to know which direction to go in.


Regards,

 

[mickyg]

well if you have a higher flow rate than what you will get from the new boiler then you need to decide whether you'll be satisfied with that or if its worth finding someone who can be bothered to take these things into consideration and give you a solution with an equal performance.

 

[D_Hailsham]

The 12.7 ltr min. Quoted by the manufacture is at a 35 degree temperature rise which is how manufactures state their flow rates. Which is too cool for normal use.

Not true.

As the hot water is not being stored, there is no need to heat it to 60C to kill off any legionella bacteria which might be present in the water, so the water only needs to be heated to the safe working temperature, which is 41C for a shower and basin and 44C for a bath. Since cold water rarely falls below 10C, and may be as much as 20C, a rise of 35C is more than sufficient. If you heat the water to 60C using a combi, you then have to mix it with cold water to bring it back to a safe temperature. This wastes energy.

 

[Luis21x]

Dan_Robinson,
Are the Intergas boilers only installed by Approved Installers ? We are based near Ipswich in Suffolk.

Are they easy to work on, and a large percentage of Engineers happy to work on them ? This is important to me, because the Powermax was notoriously impossible to get anyone to actually work on it !

Regards,

 

[Dan Robinson]

They are annoyingly simple to work on. It often takes longer to park that it does to service them.

Any gas registered installer can fit them, but you will get a a better level of service from an "approved" installer.

I am biased towards Atmos - a slightly older version of the Intergas, but fundamentally the same. Atmos are also a more pleasant company to deal with.

if a local chap can't work on one, then I would question his overall ability and whether or not you would want him carrying out such a vital piece of work in your home.

Atmos will sell the boiler direct to you or your installer (or *ahem* through me), Intergas are available through Plumbase.

 

[Luis21x]

Thanks for your help Dan.