Baxi duotec 24HE,A

[mickie]

Hi. I'm having an issue with high CO. Into the thousands ppm. The gas supply is 22mm 20mb. New gas valve. Adjusting it only makes the CO worse.

The flue is good and intact.

Any ideas guys ?

 

[ShaunCorbs]

Burner seal?

 

[newcastle phill]

Does it has rate ok. Heat input all fine ??

 

[Billy Bob Bob]

Hi. I'm having an issue with high CO. Into the thousands ppm. The gas supply is 22mm 20mb. New gas valve. Adjusting it only makes the CO worse.

The flue is good and intact.

Any ideas guys ?

Have you done a flue integrity test?

 

[mickie]

The burned seal looks alright, I'll check it again tomorrow. Same with gas rating. I'll get back. I've had the flue in bits and also run the boiler with the flue off. The CO is still high.

At some point in the past it looks like the chamber has filled up with water and theirs a water mark on the insulation. It comes upto the flame sensing electrode. I've had the main heat exchanger out under a sink and give it a good clean out. It seemed perfect. I haven't had the burned in bits tho and also don't know if a defective fan could cause the high CO.

I'll do more tests tomorrow and get back. Cheers.

 

[Billy Bob Bob]

Burner seal?

For info,would be obvious on this one if a seal had failed,if the door seal fails its always down to lack of servicing and does massive damage,never seen a manifold seal though

 

[Leo21]

Go and test another boiler with your analyser first. I had the same issue, I had to go back and re adjust half a dozen boilers when I realised what was happening.
Other than that, check the connection to,the gas valve is tight with the washer in and injector in place.

 

[mickie]

Cheers guys. I'll swap that washer. Just another little update before bed. The gas rate at max was 3.17m3/hr 34kw gross.

The injector size is 7.3mm. Supposed to be 7.5mm

Inlet gas is actually 18.5mb. There about.

The case seal is perfect. It's not pulling a draught either.

Be great if it's just a new injector washer.

I used the anyliser Saturday on a good working boiler. Come back 0.0002.
on this boiler I'm working on it maxed out the CO to 9000ppm.

 

[Leo21]

It's got to be the gas valve then surely?

 

[newcastle phill]

That heat input is well over what a 24 should be putting out.
Injector size isnt a million miles away from the 7.5mm for the 24/28 Could just be measuring innacuracies with it being so small to handle ??

 

[mickie]

Baxi tech seemed to think it was a 33kw pcb but then said it wouldn't matter if it was sending 240v to the gas valve. He said the gas valve should be adjustable.

He wants me to check the CO with the front cover off and also seemed to think it was the flue. Even though we know it's using too much gas. Not that helpful.

 

[mickie]

I measure the injector with some proper calipers. The posh ones with a digital display. I haven't changed the washer yet.

 

[mickie]

Update, I'm an idiot, I assumed the new gas valve was set up right, turns out i just needed to spend a little time with a couple of Allen keys..

min now 8.4%CO2, CO 14
max now 8.7% CO2, CO 68

 

[Leo21]

They always need adjusting,even on a service.