Re: Know about plumbing?

1) > Mains in I-> 3bar pressure regulator ->Boiler-> Safety valve ->
> I> heat
> exchanger>I

2) > Mains in---cold water inlet--4.8bar-----------------> Tank -> Hot
taps
> and shower

>Well it's very similar except the regulator on the secondary circuit (2) is
>3 bar not 4.8 bar
I don't understand why there needs to be a pressure regulator on that
side of the circuit. This would be the case only if your supply
pressure exceeds 120 psi or so ~ 8.5 bar! Check this out:
http://www.popularmechanics.com/home_improvement/home_owner_clinic/1275231.html
and:
http://www.askthebuilder.com/192_Water_Hammer_-_How_to_Stop_the_Bang_.shtml

(talking about inlet pressure reducing valves) "Factory settings are
usually between 50 and 60 PSI. I happen to prefer a setting of 70 PSI.
Settings at or near 70 PSI allow you to take vigorous showers." That
would be 4.8 bar
> and there is a 3 bar safety valve in case the tank boils.
Well that is the job of the TPR valve which usually vents out the top
of the tank into a drain. These are both thermostatic 210ºF and
pressure 150 psi (10.32 bar!!) all US figures. See:

http://www.usinspect.com/WaterHeaters/HWaterTPRValve.asp

and these not only prevent boiling but conditions were a hot water
heater can become superheated and explode. Think of a 50 gal
superheated steam rocket!

>I think I need to find data on the tank to see if I can replace these two
>with 5 bar parts.
I think we're talking about separate issues here with the 2 valves.
Make sure that second valve is a TPR valve and blows off to the
outside. These will have a manual overide so they can be checked
regularly
>The primary is sealed and topped up by a tap rather than a regulator. This
>tap is normally closed and almost never needs to be used. Perhaps once in
>the last five years?
This primary would also have a TRP valve and that's good that's good
there's a valve because as it seems the way your system is hooked up
there is the chance of backflow from the boiler into the hot water side
of your system.
So if this valve is closed the inlet pressure regulator is out of the
circuit?
I think the inlet water pressure of your hot water supply tank could be
at city pressure unless that exceeds 8.5 bar or so.
I just looked at this indirect system and they also recommend the use
of a cold water inlet pressure releaf valve set at 150 psi.

http://www.johnwoodwaterheaters.com/pdfs/GSW_Indirect_Installation_Manual.pdf
This would also blow off into a drain.

.

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