Water dripping from boiler flue pipe near ceiling. CanUhelp?

[CraigUK8]

Hi folks, new to the forum first post seeking advice. Can you help?
I have a Worcester Danesmoor 20/25 Oil Boiler which I suspect is about 18 years old. Since moving into the house 18 months ago there has been occasional water dripping from where the flue pipe enters the chimney. It seems to be coming down the chimney hitting the bottom plate then dripping down around the flue pipe. The chimney is I believe fitted with a circular clay liner (house same age as the boiler).

To rule out rain water ingress I recently had the chimney stack all re-pointed and a rain cowl fitted. The roofer however did say that the stack was in good condition.

Following that came high winds and lots of rain, no problems with water dripping. However now with no wind or rain and much colder outside temperatures after 60 mintues of the boiler coming on the water starts dripping. We only have the boiler on for 5 hours each evening. Last night about half a litre of water dripped until the heating went off when the dripping stopped. Tonight after 3 hours of it on the water has now stopped dripping (not as cold outside).

So this leads me to suspect that the issue is due to the combustion products condensing on the chimney walls. Especially in cold external temperatures and little wind and possible low up draught. Am I on the right lines?

If so how can the problem be cured?

What kind of specialist tradesperson should I seek for advice? I am at a bit of a loss and any advice will be much appreciated. I am even wondering if the chimney might need a brush up it to ensure no partial blockages before spending a lot of money.

Oh our boiler was recently serviced and deemed in good condition for its age.

Cheers
Craig

 

[Boilerman2]

An 18 year old Danesmoor SHOULD have been fitted with a Stainless Steel Liner up the chimney
Clay pipes cause rapid ccoling of the flue gasses which cause water to run down the inside of the Chimney, this will then leak out wherever it can
the Viterous Enamal flue pipes should be fitted with the Female socket upward so that any condesate will run back to the boiler, and not leak down the outside of the pipe

The best advice is get a flue liner fitted!

 

[CraigUK8]

Hi Boilerman
I much appreciate your prompt response, thank you.
The female socket of the flue pipe is pointing up but the vertical section that slides down into it protrudes upwards into the chimney and my guess is that the condensation is running down the clay surround settling on the base plate and finding its way out as you suggested.

In respect of getting a liner fitted, can you recommend any good firms in the Lincolnshire area for a quote?

Also is this an expensive job and if so should I think of getting my Danesmoor boiler replaced at the same time, or are these units from your experience good for a good few more years?

Cheers
Craig

 

[Boilerman2]

The average Oil fired boiler is good for 20-25 years, so probably a good time to go for a new boiler - Grant Vortex condensing boiler would be an excellent choice

 

[CraigUK8]

Hi Folks

Update nearly 2 years since this thread was started:

The flue/chimney condensation issue with my 20+ year old Worcester Danesmoor 20/25 boiler got progressively worse with the plaster ceiling surrounding the flue pipe starting to crumble around it due to being soaked daily from the condensation dripping down.

A couple of weeks ago I decided to get a different firm in for the annual service of the boiler. The chap that serviced it for the last 3 years used to take about 30 minutes all in. The new chap told me that you can not properly service a boiler like this in 30 minutes. He spent 2 hours. He took everything apart and ended up with a problem as when fitting things back, the oil pump packed in and failed to deliver the pressure required to atomise the fuel. He replaced that with a used unit free of charge. He also replaced a filter, the fuel nozzle and the flexible oil pipe.

Now since that service, outside night temperatures have been below 5 degrees centigrade which usually starts the condensation dripping.

To my absolute delight, there has not been a drop of condensation. And the pre-tell tale symptom of it is hearing water sizzling at the top of the flue pipe before it starts dripping. There has been none of that. Early days yet as the acid test will be when the outside temp goes to minus figures.

The other change noticed is that during the first 30 minutes of firing up the boiler, we had a smell of it like an oil smell. That smell has disappeared.

So I suspect that this issue may simply have been all about having the boiler properly serviced with attention to detail.

And when I consider that this boiler was installed when the house was built 23 years ago, the condensation issue I guess would have been evident from day one and fixed by the previous owners if it had been the result of a bad installation.

What are your thoughts?

Cheers
Craig

 

[Suffolkrenovator]

Having exactly the same problem and think this may have started since our boiler was serviced. Was the origin of the problem the low pressure? I'm going to ask our servicing company for their thoughts.

 

[CraigUK8]

Having exactly the same problem and think this may have started since our boiler was serviced. Was the origin of the problem the low pressure? I'm going to ask our servicing company for their thoughts.

Hi, sorry for the delay in my reply. The (newly used) service engineer that did a thorough job of servicing the unit did not say what may have caused the previous issue. He gave no promises of his service efforts fixing this issue also. However he did replace two components in the process and forgive my lack of knowledge as I don't know the proper names for them.
1) Was a brass like nipple that supplies the oil spray in to the burning chamber.
2) Was the pump that forces the oil through the pipe and the nipple. The original pump unit upon reassembly, failed to work thus was replaced free of charge.

Since that service our boiler has worked perfectly with zero condensation dripping issues.