Strange happenings servicing a Duotec

[AllyBongo]

Servicing a 40Kw Duotec today, on high burner the FGA readings were spot on, I had to take a call so took the FGA out and turn off calibration mode. Tested it again 5 mins later and the CO2 was only at 5.9% and the CO was slightly higher but not at a worrying level. Ratio was at 0.0012. My FGA is due calibrated next week, but its strange it was bang on the first reading. The boiler is 3 years old. I've left it as it is and am going back to strip and clean the heat exchanger once my FGA is done. Cant see my FGA messing up in that 5 mins, but also cant understand the boiler changing so much when nothing has changed!

Any clues fella's?

 

[Ermintrude]

Modulated down? Your supposed leave it burning for a few mins before u test

 

[AllyBongo]

Was still on full burner, its a big system and i had the HW running. Had been on for about 5 minutes both times and my FGA was in it for about 5 minutes too

 

[Ermintrude]

Pooh pooh! What was inlet and gas rate like? Was it a he or ga?

 

[AllyBongo]

Inlet was 18mb. GA???

 

[Ermintrude]

GA is the duo II ( flap in middle)

Duo he is the old one with lift up door and blue badge in center of door.

What was the gas rate? 4.6? Sure inlet is supposed to be min of 19?

If inlet low gas rate generally higher?

 

[AllyBongo]

HE it is. I didnt get the gas rate. MI's say 20mb for inlet, cant see that being the problem though if 40 CDi's min is 18mb.

 

[gassafe]

HE it is. I didnt get the gas rate. MI's say 20mb for inlet, cant see that being the problem though if 40 CDi's min is 18mb.

A Worcester CDi or any boiler minimum is 16.5mbar allowing for the 1.5 Mbar drop on pipework to gas valve! This would mean your only getting 19.0 at meter of course etc...

 

[Ermintrude]

So your inlet was low fga wrong and you didn't gas rate? Senior engineer for Eon or British gas?

Gas valves arnt invincible!

An. 837 is 16.5mbar

A ariston is zero as it's never working

Each mi is different . You cannot make assumptions like that.

 

[AllyBongo]

Haha!

Wouldnt rate 18mb as low as meters are 21 +/- 2. Boilers wont be made to work above this range

 

[Billy Bob Bob]

Haha!

Wouldnt rate 18mb as low as meters are 21 +/- 2. Boilers wont be made to work above this range

its low for this boiler it is essential you have 19 min at the inlet

 

[Ollieg]

Inlet working on new ecotec 2 is 13mb...... Wtf.

 

[Ermintrude]

Inlet working on new ecotec 2 is 13mb...... Wtf.

No it's not. Baxi say it will function as low as 13mbar. 40kw must have min of 17mbar (GA range)

Boiler needs to e installed in accordance with pipework standards.
21 +/- 2 and one for losses on gas line. Hate it when mfrs out stupid stuff on promo and instructions.

 

[Ollieg]

Vaillant eco tec2 13 mb inlet on max rate.
Drop on pipe work between boiler and meter still should not exceed 1mb. Only way to check is to cut in an extra test point.

 

[SafeGasInstall]

Must be undergas as in 5min you had it on it did not rich it's max ! 40kw will need 28mm gas supply if gas run is longer then total of 6m (dimmension is guesstimate based on expirience )
I will only install 40kw on 22mm if gas metter is on the outside wall (on the back of the boiler and gas run is no longer then 2m(even then it could be undergassed)

 

[Ermintrude]

Thought 837 was def 16.5 at valve.

But on about page 6 states requires 20mbar at inlet

 

[AllyBongo]

After being back at this, everything was testing fine. High and low burner just needed slight adjustments to get them spot on, spent a bit of time at the boiler and ran it through calibration tests a few times, left print outs of high/low settings. The customer called to say the boiler was noisy and vibrating a week later, back at it today, when it goes into low burner, shaking and struggling away! FGA readings on high perfect, but CO sky high on low. Called Baxi, who said to reset the low adjuster on the gas valve. Now working a treat on high and low. Strange one but glad everythings working. If anyone comes across the same to reset the low adjuster is, turn it fully clockwise then 4 turns back out, that gets it back to the factory setting

 

[arran197]

Of you had the tap running then it was a waste of time, in service mode it operates the ch only. Did you put it in service mode?

 

[beesley121]

After being back at this, everything was testing fine. High and low burner just needed slight adjustments to get them spot on, spent a bit of time at the boiler and ran it through calibration tests a few times, left print outs of high/low settings. The customer called to say the boiler was noisy and vibrating a week later, back at it today, when it goes into low burner, shaking and struggling away! FGA readings on high perfect, but CO sky high on low. Called Baxi, who said to reset the low adjuster on the gas valve. Now working a treat on high and low. Strange one but glad everythings working. If anyone comes across the same to reset the low adjuster is, turn it fully clockwise then 4 turns back out, that gets it back to the factory setting

When making adjustments on the gas valve, do you reset the boiler a couple of times and ensure the readings are the same as I've found some don't stay at the same settings and Ned to be readjusted

 

[AllyBongo]

Of you had the tap running then it was a waste of time, in service mode it operates the ch only. Did you put it in service mode?

Pretty sure the water was hot...... Maybe not though.


I had this boiler tested a good few times after resetting it

 

[AllyBongo]

Yeah, was in calibration mode