heatline c24

[stevep]

I have a heatline c24 condensing boiler.central heating works fine at 85'c,hot water will work at 65'c,but only if i reduce cold water flow rate to 40% of mains pressure,any higher and hot water is luke warm.any idea what the fault is at the moment it takes half an hour to run a bath.
Have replaced dhw sensor,diverter valve.
Cheers

 

[wnjswozo]

sounds like incorrect gas supply to boiler,ie not piped up right,you need to gas rate or fga to rule this out.see it a lot where combis not piped up right

 

[stevep]

thanks for reply,can you explain what gas rate/fga is?
cheers

 

[newbie1]

firstly incoming pressure might be too high this leads to boiler being unable to keep up with the flow
secondly do not attempt to play with the gas yourself
you need a registered gas engineer to examine you gas supply pipe and to gas rate it
some combis are fine on 15mm supply pipe but others need 22mm you need to check the paperwork supplied with the boiler this will tell you what supply pipe is needed
this is not a diy job

 

[Kip]

Gas Rate would be the free option unless you wish to spend 700 quid on a machine which is the fga(flue gas analyser)

To Gas rate, dependent on your meter (metric is a dial of numbers) and (imperial is a rotating hand)

For metric:

Record your start reading, run your hot tap for on full for 2 minutes then record the end reading. Calculate the difference and times is by 321.

For Imperial

Time how long it take for the dial to do one full revolution and times it by 1664.

Now its been a while since ive done gas rates this way, i take the reading and look in the corgi handbook. So if ive got the calculations the wrong way round feel free to correct me.

 

[newbie1]

he wont get accurate reading because its not operating correctly as the flow rate seems wrong at 30mins to run a bath
first step is get someone to check flow rate of mains pressure and then check inlet gas pressure to see if these are correct
check incoming pipe size and length of run
it really is not a diy job too many variables

 

[stevetheplumber]

a 24kw boiler will produce about 8 litres with a 35 degree rise in a minute use a jug to time the flowand see if your getting this

 

[newbie1]

i predict next question will be what sort of jug

 

[REDSAW]

i predict next question will be what sort of jug

dont be silly,
whats a jug?.

 

[Kip]

he wont get accurate reading because its not operating correctly as the flow rate seems wrong at 30mins to run a bath
first step is get someone to check flow rate of mains pressure and then check inlet gas pressure to see if these are correct
check incoming pipe size and length of run
it really is not a diy job too many variables

Correct he wont get an accurate reading, thus pointing out the pipe sizing would be incorrect.