Potterton Profile/Prima inner flue tubes

[Puddle]

Just thought I would bring up the subject up for the newer gas registered plumbers about the need to double check the flue terminal construction and inner tube condition of flues on the Potterton profile,prima and profile Neta heats
They are coming to a age now were the terminals and inner exhaust tube are becoming brittle,if not split due to the years of high temperature gases being passed through them
I have had to replace quite a few over the last year due to above and thought would just mention,so others, double check this situation and make safe by replacing were required,you can purchase the inner flue tube and attached terminal as a spare part

 

[CMairiD]

We are seeing lots of Primas like that.

 

[Spudhater]

Pottertons dont you just love them .............Not!

 

[Toddyplumb]

Just replaced a Glowworm , British gas wanted to replace the boiler !
Mind you I think manufacturers / suppliers have latched onto this £90 for flue and turret elbow !!!!!

 

[grahamgas]

The last 2 profiles I have seen have had damaged flues!!
One of them was given the all clear 2 weeks before on a LGSC, but had clearly been damaged longer than that.

 

[Plucky]

Would a damaged flue prevent the air pressure switch from operating?

 

[grahamgas]

On one of the damaged ones mentioned above, all was working as it should.The one that wasnt was the one that had recently passed the LGSC!

 

[ferret]

i,ve had a few suprimas as well totally rotten at the terminal end , easy replacement though , happy days!

 

[MBPlumb]

I have been to look at a potteron profile prima, with corrosion to inner tube on inspection the external one has been damaged on installation, no MI's with it or though I have found some online. It looks as though the boiler will have to be removed to replace the flue and sealing rope, Is this so? Not sure if it is economical do this given the age and condition of boiler would a replacement be the best option for the labour involved? Any opions/help on this?

 

[tamz]

The boiler will have to come off the wall to replace the flue as it has a square plate on the inside which bolts to the boiler.
The flue had to be fitted before the boiler.

It is no big deal to remove it, about 8 screws.

 

[Reg Man]

Yes: there are quite a few old pottertons with rotten flues. This will not effect the pressure switch and the boiler will continue running. The problem is, products of combustion will re-enter the boiler causing problems with the combustion, resulting in high levels of carbon monoxide.

 

[oldplumber]

This was mentioned by my gas safe inspector and he reccommended that one should use your fga to check the poc and then check the inlet side for poc contamination and take a print off of both to cover your arse in the future, good advice it would seem.

 

[Reg Man]

Good way of checking is combustion test. Great if its on the ground floor, then you would probably see it to. The hole will re circulate its products of combustion, causing vitiation at the burner and high levels of carbon monoxide.

 

[PaulGas]

Ive had some that work and pass all test fine with this problem. Ive had some that fail with the FGA...Ive had them that wont actually light becuase of this problem... Its even more fun to change when the installers have cemented around the flue and covered the screws!!

 

[CMairiD]

This was mentioned by my gas safe inspector and he reccommended that one should use your fga to check the poc and then check the inlet side for poc contamination and take a print off of both to cover your arse in the future, good advice it would seem.

Now here's a question for you ...

Was talking about this technique with one of my training engineers the other day. He said it sounded like a good idea, but what would happen if the flue had rotted more than 200mm into the air intake? Given that the boiler is sucking air in, would the FGA actually pick up POCs in the intake?

Probably a silly question, but I had to ask ...

 

[Reg Man]

That why there are two combustion test holes on modern boilers. Test points generaly located on the flue turret of concentric flues. One tests the out let exhaust gases ie: looking for CO:CO2 ratio normally better than 0.0002 for band A appliances. The other test hole is for the air intake, What you look out for is adnormallities with readings of CO, C02 and possible reduced 02 (less than 20.9%). This is very useful for checking boilers with long concealed flue runs invoids, to ensure the integrity of the flue ie: it aint come apart.

 

[shorticus]

That why there are two combustion test holes on modern boilers. Test points generaly located on the flue turret of concentric flues. One tests the out let exhaust gases ie: looking for CO:CO2 ratio normally better than 0.0002 for band A appliances. The other test hole is for the air intake, What you look out for is adnormallities with readings of CO, C02 and possible reduced 02 (less than 20.9%). This is very useful for checking boilers with long concealed flue runs invoids, to ensure the integrity of the flue ie: it aint come apart.

I'd just add to test the supply air at the test point with boiler casing on, otherwise depending on the model you could be analysing the room air, sounds obvious but I nearly made this mistake a few weeks back myself