Combi Boiler

[ajayksagar]

i recently changed to a combi boiler and have now been told that i should remove the pump which is in the loft that operated my power shower, is this correct.
Since the installation i have seen a dramatic reduction in water pressure even when no one is opening a tap elsewhere and the shower water goes hot and cold during a 10 minute shower. Now i am told i might even need my raditors flushed.
help someone please!!

 

[jj4091]

I am not qualified in this area, but have experienced similar problems, the output pressure of a combi boiler is inferior to a gravity fed system(usually) & in winter you may find that you have to reduce the flow rate at the tap dramaticly in order to get water hot enough to bathe/shower in, I seem to recall that combi boilers are designed to raise the temp. of the incoming supply by 37degrees, so they do not heat up the water as well in winter as they do in summer.As for your shower if it is a thermostatic type then it could be one of 2 things, either the cartridge in your mixer is faulty or,more likely, your boiler was not set up properly at instalation.Sorry do not know about the power shower pump.edit.But on second thoughts if you suspect the pump is causing the problem then isolate the power to it & try a shower without it. The best answer though is probably to contact the pump manufacturer & ask them if your model is suitable for use with a combi. Try a google search if you do not have their details

 

[mystified2]

We recently changed to a Combi system and there's no doubt it is an inferior one........when you run the hot water or shower or bath the central heating is actually switched off.......so be wary of someone telling you to flush the radiators........and the pressure is absolutely hopeless..if we could have our old syatem back we'd do it tomorrow!

 

[clf-gas]

Would appear you all have been given bum information and sold a combi when you have low mains pressure and flow.

with a combi you should'nt need a pump for the shower.
a combi on good pressure and flow is better than a gravity system.

also cold showers and poor flow will not be cured by flushing the rads, thats a £400/£500 hoodwink.

 

[sandwell]

ajayksagar

You really ought to get your installer back again, these things should not happen if the supply pipes etc have been correctly sized, and the boiler is the correct size for the job.

 

[Rotunda82]

You shouldn't have a shower pump with a combi boiler - when you have a combi installed you can get a mixer shower designed to handle higher pressures - eg Mira 415 combiforce mixer shower

Also as mentioned if the incoming cold water supply is not adequate ( pressure wise ) then a combi boiler wasn't the best choice

 

[Fluffster]

Eitherway the system should have been flushed to bench mark standard otherwise your manufacturer warranty is invalidated.
Flow rate should have been tested prior to installation v easy to do just use a graduated container and time how long it takes to fill one litre then work out what that equates to in a minute.
Pete