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pressure loss
A loss-of-pressure-control accident (LOPA) is a mode of failure for a nuclear reactor that involves the pressure of the confined coolant falling below specification. Most commercial types of nuclear reactor use a pressure vessel to maintain pressure in the reactor plant. This is necessary in a pressurized water reactor to prevent boiling in the core, which could lead to a nuclear meltdown. This is also necessary in other types of reactor plants to prevent moderators from having uncontrolled properties.
Pressure is controlled in a pressurized water reactor to ensure that the core itself does not reach its boiling point in which the water will turn into steam and rapidly decrease the heat being transferred from the fuel to the moderator. By a combination of heaters and spray valves, pressure is controlled in the pressurizer vessel which is connected to the reactor plant. Because the pressurizer vessel and the reactor plant are connected, the pressure of the steam space pressurizes the entire reactor plant to ensure the pressure is above that which would allow boiling in the reactor core. The pressurizer vessel itself may be maintained much hotter than the rest of the reactor plant to ensure pressure control, because in the liquid throughout the reactor plant, pressure applied at any point has an effect on the entire system, whereas the heat transfer is limited by ambient and other losses.
Hi all. New to this forum, so be gentle with me. I've got a Sabre (rebranded vokera I believe) boiler with an ongoing problem.
When the heating is on, the pressure holds fine, when it's off the pressure drops, the red light of death comes on and I have to reset and top up via the loop. My...
I would be great-full if any one has any advise on pin pointing where I could be losing pressure in my CH system.
I have a 2 1/2 year old Sabre 29 HE Condensing Boiler which seems to be losing pressure by the day, approx 3/4 Bar.
Before I noticed this the system usually needed a wee top up...
weejoe
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boiler
help
pressurepressureloss
should
system
water
This is my first ever forum post so please be gental.
I have a Halstead platinum combi boiler and over the past 18 months its been losing pressure and I have to pump it up every 1 or 2 days. I've had a halstead engineer out to it twice and paid over £180.00 for him to tell me he couldn't find...
hello all
ive got a problem with my ideal c80ff (not ideal i know!!)
ive had water leaking from my prv which meant topping the boiler up nearly everyday. after browsing the forums i checked my expansion vessel for damage to diaphram/ air pressure.
after depressing the valve there was no...
andy16v
Thread
combi
expansion
expansion vessel
no water
pressurepressureloss
problem
valve
vessel
water
which
Dear all,
I've got a quesionnaire to hand in tomorrow and just realised i've missed off one question. I haven't found anything in the user guide so i was wondering if i could pick your brains.
Can anyone tell me 2 main reasons for excessive pressure loss in a gas carcass.
I thought one could be...
I am having a problem with my gloworm swiftflow boiler. Pressure drops to zero after 2 days. cannot find any leaks. If I re-charge to half a bar, boiler starts and settles at 2 bar.
can anybody suggest my next step. ps. I am a DIY.
cheers
BERNI L
BERNI L
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bar
boiler
ceiling
concrete
condensate
diy
drain
expansion
expansion vessel
fan
flow
hose
leak
leaking
no water
pipes
pressurepressureloss
problem
valve
vent
vessel
water
Hi,
First off - I know nothing about plumbing. Having spoken to Vokera helpline today they say we need to re-pressurise the boiler as it is on 0 and should be on 1 / 1.5
The boiler is attached to a megaflow system. Having read the boiler instructions, and seen the youtube videos about filling...
Geoggy
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bar
boiler
brass
cylinder
difficult
filling loop
fitting
help
hose
inside
megaflow
mynute
pipe
plumbing
pressurepressureloss
problem
system
tap
valve
vokera
water
Hi all, I know this is going to sound odd but this is the problem. I live in a bungalow so great for running the pipe work in the loft. I need to put a rad on a wall but I can't drop the pipes from directly above. I can come down a nearby wall then run horizontal. This is great until I need to...
locsuna
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bungalow
difficult
find
flow
high
loft
pipe
pipes
pressurepressureloss
problem
system
wall
work
Hi all, if the expansion vessel on a boiler has a problem and the prv disharges to relieve the pressure, how much does it relieve it? Does the guage go to zero or just down a tad?:confused:
sparky
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bar
boiler
cold
expansion
expansion vessel
guage
hot
oil
pressurepressureloss
problem
system
valve
vessel
water
Hello everyone, I'm new to the forum... and would appreciate a little help?
I have a water pressure leak in my boiler warmflow "90 HE pumped". It is just over a year old.
I changed out the expansion vessel - pin hole leak in the bladder... the system held pressure for 2 days (2.5 bar) 25 deg...
JimH
Thread
bar
boiler
boilers
cold
condensing
condensing boiler
expansion
expansion vessel
hose
hot
hot water
leak
loft
oil
pipe
pressurepressureloss
problem
radiator
radiators
secondary
system
tank
telford
temperature
vessel
warmflow
water
water pressure
Hi All,
New on here although I have been reading the last few days.
I had a Potterton Performa 24 Eco HE Boiler fitted 4 years ago, never had a problem, I have a British Gas Homecare agreement just in case as my last boiler was a NIGHTMARE!
Anyway, had a new bathroom fitted last week...
parrot&glue
Thread
air
assistance
bar
bathroom
boiler
central heating system
concrete
connections
eco
gas
hot
oil
pipes
potterton
pressurepressureloss
problem
radiator
safe
safety
system
towel rail
valve
valves
Hi there,
I am trying to help my sister with a problem that is baffling me. She has a boiler that heats a swimming pool and three small radiators. The pool heats via two small heat exchangers. It is a sealed system with Expansion Vessel, Air Release Valve and Emergency Pressure Relief Valve. The...
Bradfield2010
Thread
air
bar
boiler
expansion
expansion vessel
flow
hot
leak
newbie
oil
plumber
pressurepressureloss
problem
pump
radiators
sealed
system
test
valve
valves
vessel
water
Hi all
I have a boiler problem and I've had a bloke out to look at it. It seems that the repair is going to set me back a fair amount so I'm just after some confirmation of what the engineer said.
Some background: I came back to find my boiler had stopped working due to low pressure. I've...
davelee212
Thread
air
bar
boiler
central
central heating system
cold
cylinder
flush
gas
hot
job
pipe
potterton
powermax
pressurepressureloss
problem
radiator
radiators
reset
system
valve
water
Hello all
I hope someone can help as we have been having a total nightmare with our boiler :(
Our boiler has been losing pressure now for the last few months, we have had several British Gas engineers round who have tried, putting sealent in the system (3 times), bled the radiators, checked...
athlk
Thread
bar
bleeding
boiler
ceiling
central heating system
combi
combi boiler
cylinder
gas
hot
hot water
hot water cylinder
inside
leak
oil
pipes
pressurepressureloss
radiators
remove
safe
safety
system
test
trv
valves
water
I have a problem where my boiler keeps losing pressure. I have had a new boiler fitted in the last few months but have/had the problem with both the old and new boilers.
It seems that when I go around and bleed the radiators etc. the problem becomes even worse in so much as when we get up...
mbird59
Thread
air
bleed
bleeding
boiler
boilers
central heating system
cold
combi
combi boiler
copper
cylinder
expansion
high
hot water
leak
oil
overflow
pressurepressurelosspressure problem
problem
radiators
showers
system
vessel
water
im totally stuck with a central heating system i installed last may. everything was working fine until last dec when i got a fone call from the customer claiming that the pressure on her boiler had dropped to zero. the boiler itself is a worcester 40 cdi and was fitted onto an existing open vent...
bigbeak07
Thread
boiler
central
central heating system
copper
expansion
expansion vessel
find
leak
lockshield
pipework
pressurepressureloss
prv
radiators
rising
sealed
sealed system
system
temperature
trv
valves
vent
vessel
worcester
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