Baxi Boston 2 OF 50 - Spilling when very cold

[pipee]

I have recently moved into a house with a Baxi Boston 2 OF 50. Pilot light kept going out, discovered it was the Thermocouple knocking it out. Had corgi plumber round who did flue test etc. which seemed to be the problem. He replaced Flue and corrected it to what it should be. However when it is very cold it still spills and knocks out the pilot. I can get it going by turning the bolier on and off for 30 secs at a time and eventually the flue is hot enough and it will pull. But it seems over night that the pilot is not keeping the flue warm enough so when it starts up in the morning it just cuts out. Once I do get it running it is fine for the day. Plumber has been back on several occasions but says there is nothing else he can do as the flue is now sound and passes the checks.

Anyone got any suggestions on what we could do as I really don't want to get a new boiler just yet!

Thanks

 

[pannierstan]

Keep the thing ticking over all the time. God its cold enough!! leave it on 24hrs

 

[baxpoti]

Do not use a boiler that you know is spilling switch it off and rectify the problem, as flueing or ventilation is likely to be incorrect

 

[weareleeds]

How much of flue is outside? as only 3m of non insulated flue is now allowed since about 2000

 

[cross thread]

how can he ignore a boiler that is spilling, it needs sorting or turning off.check flue run ,insulation might help if it runs through a loft

 

[pipee]

How much of flue is outside? as only 3m of non insulated flue is now allowed since about 2000

Flue directly out of boiler goes up about 75cm, then turns right at about 120 degrees for another 25cm, then it goes outside up a 5 to 6 metre chimney

 

[BOB..DOLE]

I have recently moved into a house with a Baxi Boston 2 OF 50. Pilot light kept going out, discovered it was the Thermocouple knocking it out. Had corgi plumber round who did flue test etc. which seemed to be the problem. He replaced Flue and corrected it to what it should be. However when it is very cold it still spills and knocks out the pilot. I can get it going by turning the bolier on and off for 30 secs at a time and eventually the flue is hot enough and it will pull. But it seems over night that the pilot is not keeping the flue warm enough so when it starts up in the morning it just cuts out. Once I do get it running it is fine for the day. Plumber has been back on several occasions but says there is nothing else he can do as the flue is now sound and passes the checks.


Thanks

How can he say that it is sound and passes all checks when it is spilling sounds like john waynes back in town.

could be the flue lenght, bends, terminal, and how do you know its spilling just because the pilot goes out it does not mean the flue is spilling.

 

[pipee]

["BOB..DOLE"]

How can he say that it is sound and passes all checks when it is spilling sounds like john waynes back in town.

could be the flue lenght, bends, terminal, and how do you know its spilling just because the pilot goes out it does not mean the flue is spilling.

Well I suppose he has never checked it when it's been so cold i.e. 6.30am when it tries to light (although I am quite sure it has done it when it hasn't been so cold, it just seems more consistent with very cold weather).

The reason I think it is spilling is because I can feel the hot air behind the boiler (and smell it), when it is running okay there is no hot air behind the boiler. But I am no plumber, hence why I am seeking further advice.

 

[BOB..DOLE]

) The flue should be kept as short and as warm as possible.

2) Give maximum possible vertical rise from the appliance before using any bends (preferably at least 600mm (24 in)). Avoid the use of right angled bends.

3) Terminate in an approved terminal preferably above ridge height but at least above the eaves of a pitched roof.

4) If Twin-wall type flue tubing is to be used the inner tubing of the boiler adaptor must not project into the draught diverter of the boiler. A boiler adaptor which meets this requirement is obtainable.

5) An existing brick chimney should be lined with acid and moisture resistant materials such as stainless steel flexible flue pipe.This is particularly important if the flue is above 6.5 metres (20 ft) in height and not wholly internal. WHETHER OR NOT THE CHIMNEY IS TO BE LINED IT MUST BE SWEPT THOROUGHLY BEFORE THE INSTALLATION.

6) Whatever type of flue is used it must be properly supported and not simply supported on the boiler.

Page 3

 

[pipee]

how can he ignore a boiler that is spilling, it needs sorting or turning off.check flue run ,insulation might help if it runs through a loft

He has checked the flue runs (replaced one directly from boiler and done a smoke test on the chimney one). Boiler is in a kitchen (with no rads so is quite cold), could the flue directly from the boiler be insulated, if so what with?

 

[pipee]

) The flue should be kept as short and as warm as possible.

2) Give maximum possible vertical rise from the appliance before using any bends (preferably at least 600mm (24 in)). Avoid the use of right angled bends.

3) Terminate in an approved terminal preferably above ridge height but at least above the eaves of a pitched roof.

4) If Twin-wall type flue tubing is to be used the inner tubing of the boiler adaptor must not project into the draught diverter of the boiler. A boiler adaptor which meets this requirement is obtainable.

5) An existing brick chimney should be lined with acid and moisture resistant materials such as stainless steel flexible flue pipe.This is particularly important if the flue is above 6.5 metres (20 ft) in height and not wholly internal. WHETHER OR NOT THE CHIMNEY IS TO BE LINED IT MUST BE SWEPT THOROUGHLY BEFORE THE INSTALLATION.

6) Whatever type of flue is used it must be properly supported and not simply supported on the boiler.

Page 3

1 - I suppose the flue can get very cold
2 - used to be the case until he replaced it with a longer vertical rise, no right angle bend
3 - It is terminated okay I presume, he hasn't actually been to top of chimney to check but seems to think it is otherwise smoke test would fail?
4- I don't know about that
5 - It is lined, not sure what with, I think it's just about below 6.5m
6 - It is bricked and cemented in