Combi with Power Shower - really OK?

[jfrm]

We are about to replace our conventional boiler and a combi or condensing combi has been recommended. Now I love my pump driven power shower but people are telling me that with the combi, the pressure comes from the mains and will be just as powerful. Is this really true? Can the mains be as powerful as those chunky looking pumps?

thanks for any advice,

James.

 

[corgiman]

yes its really really really true

and as to the mains being as powerful, well that depends on your mains really

 

[lor]

avoid a combi
conventional boilers r more reliable
if it did breakdown you can put the immersion on (not possible on combi)
combi shower is ok as long as no one opens a hot tap
as water is preheated and stored in a cylinder the temp of the hw is more stable than a combi.[/list][/list]

 

[corgiman]

i disagree combis are just as reliable as conventional.

how many syncron motors actuators etc have you had to replace on a convetional system

every thing that goes wrong in a combi goes wrong in a conventional, just more spread about and not considered part of the boiler

 

[lor]

rubbish
i worked for a boiler manufacturer and the figures say you are very wrong.
also condensing boilers add unreliability.
common sense says more complxity = more chance of something going wrong.

 

[corgiman]

go on then tell me how is a combi boiler with and internal diverter valve, integral pump less reliable than a conventional boiler with an external diverter valve and an external pump

and are you really telling me that a modern combi boiler is more complicated than a modern conventional boiler

the only real difference now is a plate to plate heat exchanger, dhw thermister and a flow switch, oh silly me they are FAR more complicated

and there is no need to be rude we are all entitled to opinion and in my experiance is that they are about the same in reliablity

by the way which manufacturer do you work for and i will keep well away from your combis

I would only suggest a conventional system because

you are not limited to the water delivery as you can increase it with a pump

if the boiler breaksdown at least you have a back up with an immersion heater

 

[lor]

WHATEVER

 

[ChrisR]

Is this really true? Can the mains be as powerful as those chunky looking pumps?

No.

Measure what flow you have now, in litres/min. Bucket usually 9 litres.
Ordinary combi will give about 1bucket/min, poshest combi about 2.
I get 4 out of my shower, ta, at 4 bar. Not for many minutes mind, a combi keeps going.
My mains is often about 2.5 bar, but some people have 7 or 8.

 

[Paul Barker]

The reason that I prefer the old method with discreat external components is that they are cheaper to buy (as spare parts in the event of a failure) easier to replace and never likely to create a condition in which the reparer has to advise you that the boiler isn't worth it time you had a new one.

ALso mid position and zone valves can withstand the vagueries of the "normal" central heating envioronment (sludge), Combis are not designed to cope with it.

Granted installation costs are greater, more knowledge and work required on part of installer, less profit.

FAstest buck in this business is made slapping a combi on the wall with little attention to the important details.

 

[corgiman]

so no explanation then


see below

 

[corgiman]

Paul you are so right

i have lost count the amount of times i have been called in afetr an installer to a client complaining of terrible water pressure, only to turn up to a monster house with two or three bathrooms with a crappy little 24 kw combi installed in it!!! and the installer has done a bunk

out to be a law about it