Combi Boiler Minefield!

[laughing6ravy24]

...I need some help!

The current boiler in our 3 bed, two bathroom terrace is frankly, rubbish!

The flow rate to the bath means that we have to start filling it now, to get a bath tonight.

When anyone flushes the toilet, or the washing machine/dishwasher are playing, or a combination of all three, the shower/bath/sink hot water flow plummets to a trickle.

Keep getting Vaillant and/or Worcester recommended b as good boilers, but they make such a huge range I honestly end up seeing double!

Any suggestions as to what sort of Combi Boiler we need would be very gratefully accepted.

Please, please keep it simple and idiot proof.

Cheers.

 

[picasso]

have your water pressure and flow measured, these determine what type of system you can have, it doesnt sound like a combi is right for your property.

 

[kevindgas]

piccasso is probably right in that the water pressure is insufficient for a combi to function properly.

get a local RGI to come along and measure. and then get him to quote for what he thinks is suitable.

boilers are sometimes not up to the mark Ideal, ferroli, heatline are among the worst.
Vaillant, worcester, broag and remeha appear to be among the good ones
although i only use vaillant, used a few worcesters in the past.
for our budget customers we have been using the Halstead Eden recently and the 30Kw seems OK.

 

[Agile]

You dont bother to say what boiler you have at the moment but whatever it is it should give at least 8 litres per minute of hot water.

Your problem seems to be solely a low flor rate into your property.

The solution is either to remove any restrictions or replace the water supply out to the street.

Tony

 

[laughing6ravy24]

Hi,

It's a small glow warm....the flow pressure is really high but I'm pretty sure the previous owners put a small boiler in which isn't suffienctly powerfull enough to cover all the radiators never mind the hot water.

Oh..and it's knackered..lol..

Many thanks for the swift replies...hope the new info helps.

 

[Agile]

The smallest combis are 24 kW which give 8-9 li/min of hot water.

A 24 kW boiler can heat a six bed detached house!

If there is anything wrong with your boiler then it can be fixed.

Everything you have described are the result of a poor flow rate.

Pressure and flow are not the same thing.

Tony

 

[doitall]

Assuming the mains can deliver, time how long it takes to fill a 5Ltr bucket.

Then the Broag Avanta or Atmos are in the top range for reliability.

 

[laughing6ravy24]

There is a water softner plumbed in...would that create any problems?

How do you measure flow rate...?


Can fill a 5lt bucket in about 30 seconds

 

[doitall]

There is a water softner plumbed in...would that create any problems?

How do you measure flow rate...?

See my last post

Yes a water softener will make a lot of difference.

You can get high flow models.

 

[Agile]

Now you tell us!

Most softeners have a considerable flow resistance.

The best installations have a bypass so the softener can be removed easily for maintenance or replacement.

If so bypass it and see the difference.

Tony

 

[laughing6ravy24]

It's brand new and a high flow model.....honestly...have checked all this out...it's the loss of flow and water when more than one thing is working that's the problem.

Will check to see..but pretty sure it was bypassed for the boiler.

Will get back to you when Ispeak to my plumber bloke..cheers.

 

[doitall]

It's brand new and a high flow model.....honestly...have checked all this out...it's the loss of flow and water when more than one thing is working that's the problem.

Will check to see..but pretty sure it was bypassed for the boiler.

Will get back to you when Ispeak to my plumber bloke..cheers.

But that is typical combi, and unless you can get 16 Ltrs/min plus a problem you will always have.

It may pay you to look at Rinnai water heaters, and get a small boiler for the kitchen and heating.

 

[Agile]

Will get back to you when Ispeak to my plumber bloke..cheers.

Some "plumber blokes" are not very clever!

Best to look at the specs for the softener although makers dont like to give the flow resistances ( because they are often not very good ).


High flow in terms of softeners are not very high flow in reality.

Nevertheless its the flow rate into the property which needs to be measured.

Tony

 

[laughing6ravy24]

It's brand new and a high flow model.....honestly...have checked all this out...it's the loss of flow and water when more than one thing is working that's the problem.

Will check to see..but pretty sure it was bypassed for the boiler.

Will get back to you when Ispeak to my plumber bloke..cheers.

But that is typical combi, and unless you can get 16 Ltrs/min plus a problem you will always have.

It may pay you to look at Rinnai water heaters, and get a small boiler for the kitchen and heating.

That sounds interesting. The current combi is in a small utility room...could the Rinnai and heating boiler go in the same room?

PS. Would the Rinnai Twin Flow Sytem work?

 

[doitall]

You can put it anywhere provided your installer can flue it according to the regs.

You still need to check the mains flow and pressure.