Condensing Combi Leak

[WirralDIYer]

Hi I have a Worcester Greenstar 35CDI Condensing Combi.

The boiler was fitted about 3 years ago, and worked fine. Then it was moved, by a cowboy plumber, who cant be located. Since being moved it has leaked from the flue.

The flue was replaced with a vertical flue kit. The kit bought was the correct one for that boiler.

The leak is coming from the top of the boiler, where the (white) flue is connected to the (grey) pipe, just beneath the top of the boiler.

I have tried removing the trap at the bottom of the condensing drain; it empties and consists of grey sludge in the bottom, but is not clogged and does not fix the problem.

The water is brown in colour, and is the same as the water I drained from the condensing trap.

Also the pressure on the Central Heating system fluctuates. I fill it to 2-2.5 bar. It can rise to 3 bar, and after a few weeks drops to 0 (if left unnoticed).

Any ideas what the problem could be?

Thanks

 

[SeanT]

Also the pressure on the Central Heating system fluctuates. I fill it to 2-2.5 bar. It can rise to 3 bar, and after a few weeks drops to 0 (if left unnoticed).

Any ideas what the problem could be?

A leak??

 

[WirralDIYer]

A leak??

Thanks for the diagnosis.

I have already identified a leak in the boiler...as mentioned in my post. It is at the top of the boiler, where the flue joins the internal connection on the boiler.

There may very well be a small leak in the central heating system, but I doubt it. I found a few radiators that where leaking at the thermostats, but I fixed these. THere are no damp patches in the house, and currently no leaking radiators (that I can detect).

The pressure goes up as well as down. I suspect this might be independant of the leak at the flue. For this problem I am suspecting air in the pipes, for which I intend on draining and flushing the system.

Any other ideas about the flue leak?

 

[clf-gas]

The leak at the flue spigot is proberbly due to the sealing ring being damaged, (this is dangerous).

You are putting far too much pressure in the boiler, Pressure should read 1 to 1.5 bar when cold. filling to 2.5 bar will cuase you problems.

Call an RGI and have the spigot checked, expect to have the boiler capped off untill repairs are made.

 

[SeanT]

The pressure goes up as well as down. I suspect this might be independant of the leak at the flue.

Correct...

For this problem I am suspecting air in the pipes, for which I intend on draining and flushing the system.

Bleeding it might be a start.....

 

[clf-gas]

The pressure goes up as well as down. I suspect this might be independant of the leak at the flue.

Correct...

For this problem I am suspecting air in the pipes, for which I intend on draining and flushing the system.

Bleeding it might be a start.....

very clever


and your helpful input is???????????????

 

[SeanT]

I was just wondering why he would see a need to drain and flush a system to get rid of the air, just gonna end up with the same amount of air to bleed out anyway, when he has bigger more dangerous problems with his flue that you have pointed out.

 

[WirralDIYer]

I was just wondering why he would see a need to drain and flush a system to get rid of the air, just gonna end up with the same amount of air to bleed out anyway, when he has bigger more dangerous problems with his flue that you have pointed out.

I am not a plumbing expert, but if there was a leak I would expect the pressure to continually drop. Because the pressure flutuates in both direction (after I repressurize it to normal) I suspect trapped air. Trapped air is different from excess air. Excess air finds its way to the highest point (ussually a bleeder valve) and can be bled out. Trapped air however, might be at a high spot in the system where there is no bleeder valve.

Does it not make sense that removing the water from the system, and starting fresh would clear any blockage of trapped air and potentially remove the first problem.

Another problem. One of my radiators takes ages to warm up. I saw the pipes being laid so I know it is piped correctly. I suspect either the return valve is uni-directional and backwards, or there is a block in the valve. The return valve gets hot, but the thermostatic valve does not. Draining the system (or at least part of it) is necessary to fix this problem anyway.

As for the flue, I have notice a (very) slight misalignment of the flue to the boiler. (ie. it is not perfectly vertical). I never thought this a problem, but I am now expecting he damaged the seal when forcing the flue to the boiler. I need to get someone out to look at replacing the flue.

How hard is it to seperate the flue from the boiler? (after turning power off to the boiler)

I would love to name and shame this cowboy. Anyone know a (good) plumber in the wirral?