Glow worm.

[London Gas]

Hi guys,

Having a bit of an issue with a Glowworm 18hxi at the moment, went out to one today and it was leaking CO pretty badly, seal was last changed in 2010 for the graphite version, door was also slightly warped, door has been changed as well as all the insulation as this was all severely damaged, also I have replaced the flue collector as this had some staining on it, now after all of this the flame picture is pretty bad, and I am still getting readings from near the burner door but cannot pinpoint where exactly this is coming from and I am running out of ideas, flue has no signs of stress or spillage, air intake is clean. Are these prone to leak from anywhere else?

 

[GrahamM]

If burner door was warped this may have damaged the heat exchanger itself resulting in a poor seal.
If all other parts are sound (flue collector, flue, burner seal) it sounds like only plausible explanation.
Can you not pinpoint using your FGA?

 

[Last Plumber]

Just a thought.
Run boiler as if you're going to fire it but with gas off so it doesn't fire. Put LDF around the combustion chamber door and see if the fan blowing in causes bubbles around the outside.
That should pin point the gap.

 

[London Gas]

The HE itself appears to be fine i'm getting high readings round the top of the burner door which doesnt make sense as its had every seal changed.

 

[thereisawizza]

Not coming back up from the flue collector?

 

[London Gas]

Flue collector is clear zero readings there and its been replaced, nothing around the rear connection either.

 

[thereisawizza]

How high are the readings? One thing you could try is get a long probe into the flue inlet duct but from inside the boiler just to verify one of the inner seals has not been pinched when fitting.

I take it it's a short flue?

 

[London Gas]

Readings are really inconsistent ranging from 300-1200 PPM of co, gas valve is completely out of sync also flame picture is light blue with 0.0050 and 2000ppm co from the sample.

 

[Last Plumber]

Is this set for LPG ?
Only thinking out loud because of flame colour.

Other than that are there any cracks in the door or face of heat ex

 

[London Gas]

Not set up for LPG. Although the gas valve is definitely out and needs to be reset from scratch but cannot do this with a leak as its affecting combustion. I think the issue with the flame picture is primarily due to the improper combustion caused by the leakage which seems to be coming from the door but the seal is intact as its brand new. The HE is only a couple of years old it was replaced before due to having corrosion to it presumably the lower seal perished and done some damage, the casing (not the burner door) has also warped due to what must be heat damage from the burner leaking.

 

[thereisawizza]

What's the ratio at the test point? A leak would not affect combustion as the heat exchanger is under positive pressure

 

[Rabbitman]

There is a small rubber seal located where the burner mixing arm fixes to the burner flange held on by x3 screws have a sniff around there, but if it's previously suffered from seal failure then flange may have warped slightly........... As for the gas valve screw the throttle in all the way clockwise then out again 7/8 full turns that will get you somewhere near for setting the co2 on high (don't forget to set the low as well)

 

[Last Plumber]

Not set up for LPG. Although the gas valve is definitely out and needs to be reset from scratch but cannot do this with a leak as its affecting combustion. I think the issue with the flame picture is primarily due to the improper combustion caused by the leakage which seems to be coming from the door but the seal is intact as its brand new. The HE is only a couple of years old it was replaced before due to having corrosion to it presumably the lower seal perished and done some damage, the casing (not the burner door) has also warped due to what must be heat damage from the burner leaking.

If it's only a couple of years old why haven't you got manufacturers out ?
I had a commercial Baxi a couple of years ago.
I created a stink as the boiler was only 5 and the burner fell off. ( you can imagine the explosive ignition) the first 4-5" of burner was still there so it still lit !, very scary !

I asked for a new boiler and for Baxi to pay my fee for replacing it.

They did !
And rightly so. It sounds like your glow worm needs a similar outcome

 

[kb76]

Cracks in the insulation pads? If it's been burning incorrectly since heat exchanger and door were changed it could have damaged the new parts again. Agree with previous posts it should be covered by manufacturer if installed as MI's. If not sounds like a new boiler if heat ex and door have both warped again?

 

[London Gas]

All sorted found a tiny little gap in the flue where one of the rubbers had split (not fitted properly and covered up with the collar) gas valve had clearly been adjusted incorrectly the previous year and left burning poorly. The new burner door was very slightly warped and I took it back to my supplier and had it swapped. All sorted now though thanks guys.