I'll pay money for constant hot water temperature......

17 Nov 2004
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United Kingdom
I've got a Vokera Compact combi boiler (12 months old) installed in a first floor room of my house. It's cracking at central heating (quiet, heats up dead fast) but theres a problem with the hot water. When hot water is run from any tap in the house it fluctuates between napalm hot & luke warm. As we have a simple mixer shower head with the hot feed from our fluctuating combi and cold directly form the mains it makes an early morning shower a bit punishing :eek: . I live at the bottom of a valley with pretty high water pressure. Please help so that I can avoid joining a local gym to use their showers.
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bin the combi and put tanks in the roof space add a cly and hey presto problem solved :rolleyes:
must have deja-vu. thought this thread was about combis when I read the title. :LOL:

I suggest you call back the guy who installed it! I think you better get your gym membership now while they offer 12 months for price of 11!
Blimey - if only everyone replied this fast I'd have my bathroom finished by now!!! Cheers for the advice - my wife will shoot me if I suggest having the combi removed (house was in pieces during CH installation).

Could the problem be that the cold water coming in from the mains is just too powerful for the combi to heat up in a constant way? If so would some sort of regulation of the combi water inlet pressure allow me to avoid the gym. As you can guess, my experience of combi's is a bit limited (hence I need to get a bit more genned up before I call the installer :confused: ).
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incoming water pressure and flowrate is ?

flow restrictor might have been removed or you may need a prv
need the figures first tho :)
Hi Kevplumb - ta for your previous help with my Led Zep pipes :) .

Not sure how to determine what the mains water pressure is - when you turn on a direct feed cold tap it's bloody fast (fills my 6L toilet cistern in about 9 seconds). Unfortunately I'm also not too sure how to find out the flowrate. The combi pressure is 1.3 bar however I'd dare say this doesn't have antything to do with my shower/gym membership problem.
I've been told that a combi-compatable thermostatic mixer will resolve my shower dilemma. They're expensive but it's worth it so we can have a normal shower and therefore stop my wife swearing at me when the temp goes too cold.
If it fiils your 6ltr cistern in 9secs flowrate wiil be 40ltrs/min
Is 40L/min the norm? Still not sure what the prssure is but I've been assured by neighbours that it's high. I'm clearly out of my depth. :oops:
you need around 10/12 litres a min for a 35 degree rise at this time of year a lot of combis will struggle due to poor installation and incomming water temp the joys of owning a combi :cry:
whats wrong witha combi
had one for years
its the lead pipe working as a flow restrictor

apart from the side effects
which are err err ill post them shortly :LOL:
Hmmm...so it sounds as if the cold water mains pressure/flowrate & temperature during a grim Leeds winter is too much for my combi. Is there a 'thing' that can be put into the water inlet pipe as it goes into the combi that tells you the flowrate(by a gauge) and can be adjusted to suit the combi operational limits? :confused:

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