31mb standing pres at meter, 28.5mb working pres at meter, 25.5mb working pres at app

[lambchop]

Came across this today on a boiler service of a worcester greenstar 18i condensing n.g. htg & indirect hw boiler. I know standing press at meter should be max 30mb, inlet working press at boiler should be 18.5mb whereas its 25.5 mb and 28.5mb at meter.

So working pressure has to be 21 mb +/- 2 mb (sorry guys I know you all know this but just thinking aloud, and understand my train of thought) with a drop of no more than 1mb. So the figures dont add up and the pipework is undersized. The equivalent length (inc elbows is 21 metres in 22mm copper) with some elbows really close together (80mm apart), I really dont like this but a mate says it makes no difference I disagree. 18 kw boiler X 0.094 = 1.692 m3 gas required. Table says 25 metres of copper in 22mm copper = 2.5m3 of gas. Gas rated app and cam in at 19.02 kw net. CPA figure add up

I feel the difference of working pressure at meter and app = undersized pipework. As I said there is 2 close together elbows but I'm also suspicious that previous guy has increased the press at reg (illegall I know) in order to get the right gas rate. Im calling esp tmrw to sort out reg and upsize pipework to 28mm. Been a long day any helpful comments would be appreciated, thanks in advance

 

[diamondgas]

Re: 31mb standing pres at meter, 28.5mb working pres at meter, 25.5mb working pres at

You need to get TRANSCO (whoever) out Lambchop ... Not all appliances in the property have governors and depend on a certain tolerance of working pressure. If you're over gassed then their safety may be compromised IMHO

 

[lambchop]

Re: 31mb standing pres at meter, 28.5mb working pres at meter, 25.5mb working pres at

Callsing ESP out tmrw morning, there are no other gas apps in property. Does anyone think or come across someone tampering with a meter reg in order to get the gas rate?, or am I completey way off on my assumption?n, FGA is right, and pipework is within tables but more than 1mb drop? I just wanted to see what other people thought

 

[Billy Bob Bob]

Re: 31mb standing pres at meter, 28.5mb working pres at meter, 25.5mb working pres at

:iagree: sounds like the governor is knackered at the meter

 

[SimonJohns]

My personal view is, I couldn't care what the last guy did. I'm going to leave it right

It's pointless trying to work out what they may have done.

Tbh on the zero guvna boilers the gas rate will rarely be out. The gas is sucked in and will pull the gas that it needs. And if the engineer knew his bacon he could of done other things to get gas rate right without boosting gas pressure

Btw. You could have 250mb on gas valve. It'll still only be a 18kw boiler when rated

 

[diamondgas]

Re: 31mb standing pres at meter, 28.5mb working pres at meter, 25.5mb working pres at

I'm old hat "lambchop" ...... "so what if the cooker drops when the heating comes on" Things have changed however and pipe sizing is much more important than use to be IMHO...... You would benefit from getting "ESP" coz you're way over the 23mbar recommended. It could also make a significant difference on the working pressure at the boiler and you need to know what that is at the regulation standard working pressure IMHO

 

[lambchop]

Re: 31mb standing pres at meter, 28.5mb working pres at meter, 25.5mb working pres at

Maybe my suspicious mind, still a newbie. looked at seal on reg. Looked ok but not 100%. Would like anybodys opinion on putting 2 elbows so close together, (is the flow of gas effected copmared to if the elbows are a metre apart?) when I would have just pulled a set and then an elbow. If the meter reg is sorted, thereby dropping pressure, the pipework is still undersized as too greater difference in meter/inlet working press but pipework is well within tables so... maybe a partiall blocked gas pipe....

 

[lambchop]

Re: 31mb standing pres at meter, 28.5mb working pres at meter, 25.5mb working pres at

Thanks lads, good point SimonJohns on gas rate, my brain is buzzin (not just about this but had a hetic day) so going to turn in for an early one. The other guy on the firm refused to go to this one as he knows the guy who put it in. Will post tmrw if anyones interested in a follow up. Great forum & lads thanks

 

[diamondgas]

Re: 31mb standing pres at meter, 28.5mb working pres at meter, 25.5mb working pres at

If a cooker has no regulator for WP it relies on a certain WP determined by British Standards ..... I always think you have got to consider the futre as well as what you face in the present

 

[AWheating]

Re: 31mb standing pres at meter, 28.5mb working pres at meter, 25.5mb working pres at

As dimondgas has stated it can be more important on appliances that rely on the correct pressure's and have no designed way of regulating the pressures at the applaince.

some worcester bosch and other manufactures boilers may have a internal drop across its internals before the inlet test point, so check with the instructions first as some worcester bosch boilers can give a reading of 16.5mb and still be correct. (ie. 19 at meter, 18 at boiler giving a 1mb drop on pipework, then a loss of 1.5mb on internal parts to test point giving you 16.5mb)

unfortunately manufactures dont tend to have a test point on the isolation to help engineers be 100% sure that you only have 1mb on the pipework which can make things difficult if your reading are low. It also gives some bad engineers who cut corners an excuse to say its ok because it says so in the instructions.

 

[lambchop]

Re: 31mb standing pres at meter, 28.5mb working pres at meter, 25.5mb working pres at

Phoned ESP, while waiting took standing pressure at meter = 25.5mbar. Ph Jones + a 40 year veteran turns up change meter reg. Afterwards All readings correct working pressure etc.. Asked them before changing the met reg would it have affected work press reading, no definate answer giving, they had coffee and gone, more concerned about pensions (fair one).

 

[lambchop]

Re: 31mb standing pres at meter, 28.5mb working pres at meter, 25.5mb working pres at

Thanks for all your propmpt replies lads

 

[Destroyer2813]

Re: 31mb standing pres at meter, 28.5mb working pres at meter, 25.5mb working pres at

For future reference WB allow you a 1.5mbar drop when testing on the inletr test nipple on top of your 1 mbar drop

 

[AWheating]

Re: 31mb standing pres at meter, 28.5mb working pres at meter, 25.5mb working pres at

For future reference WB allow you a 1.5mbar drop when testing on the inletr test nipple on top of your 1 mbar drop

on all models new and old??

 

[arran197]

Re: 31mb standing pres at meter, 28.5mb working pres at meter, 25.5mb working pres at

The Working pressure so far out at the meter will give you problems when calculating the IWP and seeing if the pipework is undersized. Get that right first, then continue looking. So do you work for PH Jones or did you call them out?

 

[Destroyer2813]

Re: 31mb standing pres at meter, 28.5mb working pres at meter, 25.5mb working pres at

New condensing models the manuel even shows a layout drawing of the pressure drops allowed

 

[AWheating]

Re: 31mb standing pres at meter, 28.5mb working pres at meter, 25.5mb working pres at

New condensing models the manuel even shows a layout drawing of the pressure drops allowed

i only asked because your statement made it sound like all WB boilers can allow this drop and not just certain models from a certain date. So i would recommend only allowing this drop if its says so in the appliance instructions or you phone WB and confirm it. When they issued there technical bulletin about this issue it still took them a while to change the instructions so it can be misleading.