gas rating, again !!

[townfanjon]

Gents, your thoughts please - commissioning a Viessmann 30 kw combi today (fit loads of them / love em )
Gas inlet working pressure on full load =19.5 mbar.
Anylised ok, Spot on.
Come to gas rating, again full load. Metric meter 86 secs over 2 mins = 27.78 gross = 25.03 nett. I can never remember one been 5 KW out. Viessmann tec had gone home. Problem with meter ???
Thank you as ever.

 

[nysk2008]

You sure it was a metric meter as Ive never timed a metric meter over 2 mins?

 

[Killy Bing]

You sure it was a metric meter as Ive never timed a metric meter over 2 mins?

You're supposed too.......

 

[mfgs]

Not familiar with viessman boilers, but how was it on full rate? Is there a service mode to put it into which forces it on to maximum rate?

 

[Killy Bing]

So you burned 0.086 over two minutes?

0.086 x 30 = 2.58 m3/hr

2.58 x 10.775 = 27.8 kw gross
divide by 1.11 = 25.05 nett.

hmm need adjustment on the gas valve?

is is pipework correctly sized? Can you see all of it?

 

[kirkgas]

You sure it was a metric meter as Ive never timed a metric meter over 2 mins?

Surely you are mixed up here?
Metric over 2 mins ( or until reading changes just after) or how many seconds to burn 1ft3 if U6

 

[nysk2008]

my bad - just where post says 86secs over 2 mins, got muddled with imperial/metric

 

[tamz]

0.086 over 2 mins?

Not staying on full rate or meter running slow which is more common than you think

 

[townfanjon]

is is pipework correctly sized? Can you see all of it?

The meter is under the kitchen sink the boiler is above it, so as the old crow flys is only about a meter away. Its all in 22mm with a few elbows, but have not counted them. Pressure been 19.5 mbar is obviously excellent. At the moment I am undecided on either gas valve or meter.

nysk, have you had a busy day lol