Flue gas analyser probes

[engeeaitch]

Hi,

I have had my boiler repaired (British Gas 532 / Worcester Bosch Greenstar Combi) following water getting into the boiler via the flue, caused by rainwater flowing over the guttering (and a blocked downpipe). It needed a new fan, diaphragm and gas valve.

The engineer said that he could not test the flue gases, because his probe would not fit into the flue. The flue comes out of the top of the boiler, then turns 90 degrees to the left and through the wall. I have a cupboard to the right of the boiler, which gives only about 18cm between the flue test point and the cupboard wall.

So my questions are:

1. How important is it to test the flue gases?
2. Is it reasonable for the engineer to say that his probe would not fit - or should he have access to a flexible probe (assuming such a thing exists).

Many thanks for any help.

 

[Atouchofgas]

How high is the flue externally, is it possible to reach it?

 

[engeeaitch]

It's at the top of the second storey - so about 20 foot high. Could get to it via a long ladder.

 

[RPG 80]

it's preferable to test the flue gases but not compulsory, your engineer can still check aspects of the boilers operation using your meter. If you want the gasses checked out would you be willing to pay for staging/tower for him to check the flue?

Sent from my GT-I9100 using Tapatalk 2

 

[anz]

He could have done what I've done before and attached his probe to his manometer tube and inserted this into the test point, giving him plenty of space.


TOP TIP!

 

[Atouchofgas]

Your boiler has not been set up correctly, mi instructions tell you what your gsr should have done if you can not get externally I would suggest drill a hole in your cupboard to allow access to the flue sample point

 

[southcoastboile]

He could have done what I've done before and attached his probe to his manometer tube and inserted this into the test point, giving him plenty of space.


TOP TIP!

I do that as well but I dont think the worcester boilers have that type of test point. The hole would be to big to put the tube on

 

[Atouchofgas]

Yes the sample points are the size of a 10p so to big for tube without some sort of padding

 

[anz]

I do that as well but I dont think the worcester boilers have that type of test point. The hole would be to big to put the tube on

Yeah, but you can still put the tube into the flue and then cover up the space around it.

 

[villa_tom]

Yes the sample points are the size of a 10p so to big for tube without some sort of padding

Ive got a flue cap of a Worcester from when I replaced a flue. I drilled a hole, 8mm I think, in it and put some manometer tube through it and siliconed between the hole and the tube. I can screw the cap onto the flue and attach my FGA to this for when this type of situation happens.

 

[Atouchofgas]

Good idea, will remember that for the next one I do

 

[Mike Jackson]

When the gas valve has been changed on a Greenstar you have to use an FGA to set it up properly.

 

[villa_tom]

When the gas valve has been changed on a Greenstar you have to use an FGA to set it up properly.

Spot on. I'm sure if you can't take a flue sample you have to AR the boiler aswell. If the flue terminal is 20ft up like the OP says then I'd just use my ladders personally. Or contract the job out to spiderman.

 

[AWheating]

some sillcone tube on the end of your analyser probe would work fine. As mentioned it may be that your gas valve could not be changed correctly without a sample of the flue gases taken.

 

[REDSAW]

piece of 10mm copper pushed through a 15mm to 10mm pushfit, hold the 15mm end to sample point and poke probe into pipe🙂

 

[engeeaitch]

Thanks everyone for your replies. So I now know that the flue gas has to be analysed.

The repair was done as an insurance claim, but the engineer has said that he can't measure the gases, because his probe won't fit into the flue. Is this acceptable, or should I be claiming that the engineer should have a suitable meter - i.e. can I go back to the insurance company and demand that they complete this work?

P.S. I've seen this attachment here but don't know if this is what an engineer would typically use?

 

[Atouchofgas]

Yes you should demand that the boiler is " recommissioned" by the gas engineer as its been previously stated your boiler has not been set up correctly and could be classed as At Risk
With regards to the flue prob It depends on the machine your engineer is using to test the emissions as the don't all use the same connections