Gas inlet pressure

chilliano12

Really hoping someone can help here?!

My house is 9.5 years old. It’s part of an estate with over 100 houses on. 

I had my boiler serviced last week and the gas pressure at the meter is 20.5 MB but the measurement at the boiler is a huge drop reading only 4MB. 

This is obviously very alarming having a drop of a whopping 16 MB. The engineer marked it as “at risk”. 

He was really confused as the water, hob, heating all works absolutely fine and is piping hot. 

He thinks the pipework is too small at 22MB. It’s not a large house at all and only a standard boiler. 

I have taken it up with Persimmons who will not accept liability as they say they’ve had no other complaints from the other 100+ houses on the estate. 

Is there anything else it could be that’s causing this. I’ve been advised there’s no gas leak but am concerned that new pipework won’t solve the issue as it’s never been picked up on before. I’ve managed to get hold of my last service record and it shows the pressure was 18MB so again this confuses me as how can it drop so much? 

BarelySentientAI

Why do you think Persimmons should be liable for something as yet unidentified that's been fine for at least 8 1/2 years after they finished building?

Keep_pedalling

How far is the run from the meter to the boiler and what size pipe is being used? A drop of 0.5 mB per meter of 15mm pipe would be typical unless there are lots of bends in it.

One possibility is that the engineer did something wrong to create a false pressure reading at the boiler, especially as I think the boiler and your hobs would not function very well if the pressure is really that low.

Zandoni

BarelySentientAI said:

Why do you think Persimmons should be liable for something as yet unidentified that's been fine for at least 8 1/2 years after they finished building?

Because they built the house, I'd say.

Zandoni

Pipe flattened under a floorboard?

doodling

Hi,

chilliano12 said:

Really hoping someone can help here?!

My house is 9.5 years old. It’s part of an estate with over 100 houses on. 

I had my boiler serviced last week and the gas pressure at the meter is 20.5 MB but the measurement at the boiler is a huge drop reading only 4MB.

That reading is extremely low to the point where either (a) the person who serviced your boiler didn't measure it correctly or (b) something has changed - e.g. a pipe has been squashed or blocked somehow.  (b) is only likely if you have had work done on the house since the last time the pressure was measured.

This is obviously very alarming having a drop of a whopping 16 MB. The engineer marked it as “at risk”. 

He was really confused as the water, hob, heating all works absolutely fine and is piping hot. 

He thinks the pipework is too small at 22MB. It’s not a large house at all and only a standard boiler. 

This suggests that the person who serviced your boiler doesn't know what he was doing.  Whilst it might be correct to mark it as "at risk", a pressure that low will significantly affect the performance of the hob (the flames will be noticeably smaller) and I would expect the boiler performance to be significantly affected as well.

Whilst the pipework may or may not be too small, unless the pipework is very long or has many, many, many bends in it then a low pressure due to excessive pipework might be somewhere around 10mBar to 16mBar, a pressure of 4mBar says that something is very wrong.

I have taken it up with Persimmons who will not accept liability as they say they’ve had no other complaints from the other 100+ houses on the estate. 

Is there anything else it could be that’s causing this. I’ve been advised there’s no gas leak but am concerned that new pipework won’t solve the issue as it’s never been picked up on before. I’ve managed to get hold of my last service record and it shows the pressure was 18MB so again this confuses me as how can it drop so much? 

If I was in Persimmon's position, I would adopt the same stance.  A pipe isn't going to suddenly change from having a sensible pressure drop (which would have been checked when the boiler was installed) to a massive pressure drop all by itself.

As above, there are two possibilities:

1. Your gas technician has measured the pressure wrong.
2. Some work has been done on or near the pipework which has introduced a blockage or restriction in the pipe (replacing the gas meter could theoretically introduce a blockage if the person replacing the meter is careless).

The fact that the hob is working normally suggests that the pressure is not actually that low..

BarelySentientAI

Zandoni said:

BarelySentientAI said:

Why do you think Persimmons should be liable for something as yet unidentified that's been fine for at least 8 1/2 years after they finished building?

Because they built the house, I'd say.

They built it wrong nine years ago, but everything has been completely fine until suddenly now it doesn't work?

Doesn't sound likely to me, and really isn't sufficient to suggest the builder is liable.

If you did some work nine years ago and I suddenly rang you up to say it was done wrong, would you jump to accept liability?  Or perhaps you might think that it was something happened more recently - maybe even after the last test it passed?

FreeBear

Minimum pressure at the boiler is usually 17-18mbar and a maximum difference between meter & boiler of 1mbar. With 4mbar at the boiler, I would expect it to go in to fault mode and refuse to fire up.

I would suggest getting the company to send out a different engineer to do the pressure measurements again.

Zandoni

BarelySentientAI said:

Zandoni said:

BarelySentientAI said:

Why do you think Persimmons should be liable for something as yet unidentified that's been fine for at least 8 1/2 years after they finished building?

Because they built the house, I'd say.

They built it wrong nine years ago, but everything has been completely fine until suddenly now it doesn't work?

Doesn't sound likely to me, and really isn't sufficient to suggest the builder is liable.

If you did some work nine years ago and I suddenly rang you up to say it was done wrong, would you jump to accept liability?  Or perhaps you might think that it was something happened more recently - maybe even after the last test it passed?

The original builder could have put pipes in a position where it could be squashed at a later date, although unlikely it shouldn't be discounted.

chilliano12

BarelySentientAI said:

Why do you think Persimmons should be liable for something as yet unidentified that's been fine for at least 8 1/2 years after they finished building?

I didn’t say I expected them to, I simply asked them about it to see if they’d heard anything from any of the other properties as if it was a known issue then it may have been something they’d been liable for. I’ve only been in the property 2 years. 

Grizzlebeard

A possibility.

If debris was not cleared from inside the pipework when it was installed everything will work fine until years later it accumulates (typically at a choke point) and becomes a blockage.