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John Rumm
 
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Default Combi Boiler Pressure Drop

Phil Richards wrote:

All the information and some background as to how your system works can
be found he

http://www.makewrite.demon.co.uk/SealedCH.html

So my questions a

1. The boiler seems to run OK on a much lower pressure, with the radiators
at their normal heat. The only difference is you can hear air in the
system. Is it safe to keep the system running this until the engineer comes
out Monday, especially as the current cold weather is forecast for the
weekend?


Depends on how low the pressure is... some boilers will refuse to fire
without enough in the system. Sounds like yours is running OK though.

2. How on earth is a system supposed to be refilled easily when radiators
are drained out? Or is there another way of allowing mains water into the
system.


Via the "filling loop" (i.e. that hose of yours). There are two
connection points: one is a tap - this is on the cold main supply. The
other is a non return valve on the heating system. This lets water into
the heating system but not out.

The only slight extra wrinkle with your setup is it looks like someone
has screwed caps onto the filling loop connection points. This is no bad
idea since it keeps dust and other crud out of the ends of the valves
etc. You should find the caps unscrew easily by hand. No water should
come out when you take the caps off.

It is "correct" to disconnect the filling loop once the system is
filled. (basically it is another safeguard that prevents any possibility
of contaminanted dirty water out of your heating system getting back
into the drinkable mains supply)

3. How easily would it be for the engineer to get the pressure back? I only


Very easy. Connect up the loop and open the tap. Watch the pressure
guage and turn off when at the right pressure. Bleed any air from the
radiators. Top up the pressure if neccessary. Repeat until there is no
more air to bleed. See the FAQ for a full description.

hope that especially as British Gas have already examined the system (on
two occasions, once after it developed a fault, the other a service check)
they will not say I've tampered it or it is a design fault.


No, your system looks fine. Topping up the pressure is one of those
tasks that you will usually only need to do should you remove rads etc.


--
Cheers,

John.

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