"thescullster" wrote in message
...
Hi all

Looking at a replacement central heating/HW boiler and reckon I will need
something like W/Bosch 24Ri. This states a requirement of 2.67cu.m/hr of
gas.

I have a 22mm gas pipe running right across the house to the location of
the current boiler.
Assessment of length and addition of effective length for bends etc gives
23m equivalent length of pipe.
From R D Treloar, this looks to be right on the limit for 22mm dia pipe.

Also we have a gas fire tapped off this main (approx 4 m from gas meter).
This is an occasional use decorative affair claiming 6.5Kw gross heat
input required.

Does anyone know enough to comment on the viability of this install?
What would the effect be if the boiler were running and the fire turned
on?

As we have concrete floors throughout and the boiler location is as far
from the meter as geographically possible, what are the alternatives
(please don't suggest moving)?

Also I note that previously it would have been likely that this main would
serve:
Valor Homeflame gas fire
Landing gas heater
Gas cooker
CH boiler 50,000 Btu

Surely this lot would put as much if not more load on the supply?
Final question - if the gas supply pressure as measured is high, can I
take this into account in calculation? I believe 20mBar is the datum
pressure on which these figures are based?


TIA as ever

Phil


Have you seen this site?

http://www.cda.org.uk/megab2/build/pub124/sec3.htm#4.3

You need to convert BTU and kW into cu.m/hour, but you can do that from
your bill, I believe 1cu.m natural gas = 1,117 kW/h, or 1 unit ( =1
cu.foot )
=31.4 kW/H, give or take a little ( it varies with the gas content and
atmospheric pressure ).

As for your gas pressure, the usual quoted spec for an appliance at full
kilter is 20mBar +/- 1mBar, so if your gas governor gave a higher pressure
than that yes, that could work to your advantage. Remember though, the
governor attached to your gas meter only works when there is a load on i
i.e. someting is drawing gas. It will read perhaps 26mBar or higher if you
measure its output when nothing is drawing gas.

Andy.