Gas Rate Question

[Billygoat]

Hi to anyone who reads this...

Just done a gas rate on a boiler and the data plate says - 9.9 -26.9 kw

I got 11.8 kw/hr I know this is in the range but why would it be so low.......undersized pipework?
I did let it run for a about 8 minutes before I started the gas rate to allow it to warm up a bit.

Thanks yo anyone who replies

 

[diamondgas]

Old or new appliance? Does it modulate in other words?

 

[Billygoat]

sorry, yep old - Sauner Duval Boiler - F24E

 

[Davinder]

Maybe, what was the appliance inlet pressure and burner pressure, perhaps the regulator on the gas valve need adjusting?

(P.S. Still doing my gas course, so I would confirm this information with someone more experienced)





- Davinder

 

[fixter1]

did you use the service potentiometer to check co/co2 rate where correct????

 

[GQuigley67]

check inlet pressure which will let you know if the pipework is undersized, did you have it running on hot water mode ?

 

[fixter1]

bet hes gas rated in c/h and not hot water

 

[Billygoat]

It was gas rated in Hot Water Mode with hot water tap running

 

[GQuigley67]

check your inlet pressure and burner pressure with the boiler in hot water mode

 

[GrahamM]

Most have covered it, but to summerise:
Are you getting 9 liters/min flow rate?
Are you getting the required inlet gas pressure?
Is the potentiometer regulated down?
Did you take a burner pressure?

 

[Howsie]

What did the MI say? The high number is clearly with the boiler on full tilt. It's doubtful it will be after 8 mins...

 

[GrahamM]

What did the MI say? The high number is clearly with the boiler on full tilt. It's doubtful it will be after 8 mins...

The boiler should more or less be hitting the maximum gas rate after 8 mins Howsie.

 

[diamondgas]

I got 11.8 kw/hr I know this is in the range but why would it be so low.......undersized pipework?
Thanks yo anyone who replies

Well Billygoat I bet you didn't expect that many replies? Some good advice given ...

You ask the question why would it be so low? Probably because it's doing it's job and modulating. If the water flow rate in the home was low the boiler would modulate to accommodate, likewise if the temp selector was on a low setting the boiler would likewise modulate. Nothing more sinister than that! It can be real difficult to get an accurate gas rate when you're relying on max gas in hot water mode.

Tip: run the bath tap (max flow rate), turn the hot water temp selector to maximum and start your timing sooner rather than later once in operation!

 

[AWheating]

i have often left the hot water temp dial set to low, after a couple of mins you start to call yourself names!! LOL

 

[Puddle]

The boiler should more or less be hitting the maximum gas rate after 8 mins Howsie.

Why for this ??

 

[Billygoat]

Well Billygoat I bet you didn't expect that many replies? Some good advice given ...

You ask the question why would it be so low? Probably because it's doing it's job and modulating. If the water flow rate in the home was low the boiler would modulate to accommodate, likewise if the temp selector was on a low setting the boiler would likewise modulate. Nothing more sinister than that! It can be real difficult to get an accurate gas rate when you're relying on max gas in hot water mode.

Tip: run the bath tap (max flow rate), turn the hot water temp selector to maximum and start your timing sooner rather than later once in operation!

I certainly didnt expect this many replies.....
Thanks for all the replies and I after spending a little more time, I have managed to get a correct gas rate.

Modulating.......... as you correctly said above..

Cheers