Gas Blockage

[Riz]

Hi everyone,

Hope someone can help with this query.

I've just had my boiler repaired (Potterton Suprema L). The engineer mentioned that the gas pressure to the boiler was very low. At the gas meter it was fine, i.e around 19 bar (I assume that's the right units of measurement), but at the boiler it was around 5 bar.

He said there was a blockage in the pipe.

He said I'd have to get a gas engineer in to sort it (as it wasn't covered by my insurance).

Does this sound normal? Also how expensive could this be (I appreciate this is an open ended question, but assuming we don't have to take up any pipes).

Many thanks for your advice!

 

[REDSAW]

running a new gas line depending on how long... tops £200, av £120.
probable cause , dammage ie dent in pipe work. you can inspect that your self to see if in good order. however 5mb at boiler is very low. did the h.e test just the pipe or via the boiler gas valve?.
also i hope he capped of the boiler for you?.

 

[Riz]

Thanks for your quick reply.

I don't know to be honest. The boiler is working although it stops after a few minutes before starting up again. Guess that may be down to the pressure.

I was out when he called. My dad stayed in as I was at work and the engineer called me to advise me of the problem.

 

[newbie1]

2 things
he told you to get a gas engineer????what was he then
the boiler should have been isolated and warning notice issued
it may well be the regulator at the meter
fine on standing pressure but not when calliong for demand

another prime example of sloppy work..was he gas safe registered because he obv isnt aware of his responsibility as regard gas safety

 

[Mbear]

There's a possibilty that you could have black dust in the gas pipe. It can accumulate at the filter at the bottom of the gas valve on the boiler and can cause a low inlet working pressure. Simple to clean it away and once it's cleaned it will work fine again.

When I come up against this, black dust is the first thing I check after the meter govener and pipe sizing


Ps I know 'black dust' sounds far fetched, but it is a real issue and can cause problems with lock out and poor hw on combis due to low gas pressure

 

[Puddle]

Ps I know 'black dust' sounds far fetched, but it is a real issue and can cause problems with lock out and poor hw on combis due to low gas pressure

Not far fetched at all,good call,have had this a few times

Also boss white blocking fitting or pipes thread under floor with open end and rubbish getting in,boiler could of been on low pressure for years

Its all hear say,so not commenting on engineer who visited ,Most important thing is to get a gas safe plumber in to sort out asap


imho

 

[REDSAW]

is that the black dust contained in the n.g being supplied from the morcombe bay gas feilds?.

 

[Mbear]

is that the black dust contained in the n.g being supplied from the morcombe bay gas feilds?.

I've no idea mate but I 'think' (or I was told yrs ago) it comes from the internal coatings of the Mains gas pipe in the street. It's quite common it certain areas round my way

 

[migoplumber]

or maybe a squashed lead pipe.
as said above the engineer who attended needs shooting and reporting. riddor reportable.
low gas pressure ? 5 bar seems a lot to me !

shaun

 

[hamish72]

1 bar = 14.7 pounds so 19 = about 280 which would go pop

its mbar = 1000 part of bar

 

[tamz]

is that the black dust contained in the n.g being supplied from the morcombe bay gas feilds?.

I think Northern Ireland are getting it worst.
Black dust is caused by hydrogen sulphide, (the rotting egg smell), reacting with the metal pipes and producing copper sulphide.
When too much H2S is present, instead of developing a thin film on the inside of the pipe, the copper sulphide flakes off as black dust.
Has been a bit of a major problem in Northern Ireland, happening after only a few years (First natural gas in 98)

 

[stevetheplumber]

i was under the impression that provided the boiler could make minimum gas preasure it was ncs?

 

[justlead1]

Hi, Although the process in manufacturing and supply gas has changed from that of town gas. Problems similar to this were often caused by water building up in pipework dips etc, due to condensation forming on the inner wall of pipes, falling to the invert and reducing pipe size. Good Luck

 

[ecowarm]

I think Northern Ireland are getting it worst.
Black dust is caused by hydrogen sulphide, (the rotting egg smell), reacting with the metal pipes and producing copper sulphide.
When too much H2S is present, instead of developing a thin film on the inside of the pipe, the copper sulphide flakes off as black dust.
Has been a bit of a major problem in Northern Ireland, happening after only a few years (First natural gas in 98)

Some facts about H2S
0.0047 ppm is the recognition threshold, the concentration at which 50% of humans can detect the characteristic odor of hydrogen sulfide,[12] normally described as resembling "a rotten egg".
Less than 10 ppm has an exposure limit of 8 hours per day.
10–20 ppm is the borderline concentration for eye irritation.
50–100 ppm leads to eye damage.
At 100–150 ppm the olfactory nerve is paralyzed after a few inhalations, and the sense of smell disappears, often together with awareness of danger.[13][14]
320–530 ppm leads to pulmonary edema with the possibility of death.
530–1000 ppm causes strong stimulation of the central nervous system and rapid breathing, leading to loss of breathing.
800 ppm is the lethal concentration for 50% of humans for 5 minutes exposure (LC50).
Concentrations over 1000 ppm cause immediate collapse with loss of breathing, even after inhalation of a single breath.

But not to worry

 

[Bernie2]

Hmm!

Investigated the "black dust" problem some years ago. All I could find out is that some gases have high sulphur content that reacts with the inner surface of copper pipe.

I think, but I am not sure (senior moment stuff), Morecombe Bay gas has a high sulphur content.

It was so bad on one job I went too we where required to put in new carcassing.

 

[Billy Bob Bob]

personally,i have seen black dust take out a few gasvalves over the years,seems to affect aristons sit valves for some reason,swansea seems to be a problem for this phenomenon