Calling Oilhead :)

[WhatNext]

Hi there

I was wondering if you could help me ?

I have read your comments about corrosion inside oil fired condensing boilers when the return temperature is low. I have a Grant Vortex System Boiler 15/26kW and I think that the leak that I have, below the boiler, could possibly be due to corrosion ?

I am struggling to understand how this particular corrosion happens ? I understand that it has nothing to do with the condensate nor the flue gases.

Would you be able to explain one again how this corrosion happens ? The system is fully dosed with Fernox Protector, in fact it has been overdosed so as to be sure that there is no system corrosion.

I have an UFH heating system on the ground floor - this has a self contained mixing manifold - the flow temperature is 50 deg C - the return temperature is 40 deg C once up to the operating temperature.

I also have another UFH system in the first floor - this also has a self contained mixing manifold - the flow temperature is 60 deg C - the return temperature is 50 deg C once up to the operating temperature.

There are also 2 conventional radiators on the system together with 2 heated towel rails which run at the flow temperature from the boiler. The system has been balanced.

Based on this I am confident that the return temperature is not below 40 deg C once the system is up to the operating temperature, nevertheless the boiler is leaking at the bottom ??

I look forward to hearing from you and thank you in advance.

 

[WhatNext]

Hi can you possibly help ?

 

[Madrab]

You'd possibly be better PM'ing him

or marking the thread @oilhead

 

[oilhead]

Hi What next,
I doubt your Vortex is leaking through corrosion, more likely to be poor welding. Older boilers, both gas and oil, particularly where they were oversized suffered from corrosion around the return ports if the return temperature was too low and caused condensation. Gravity HW systems were particularly vulnerable.
How old is your Vortex? Where is the leak?

 

[WhatNext]

Hi Oilhead

Many thanks for your reply.

The boiler was installed in 2006 - it is a system boiler.

The leak ( which is crystal clear water ) is appearing right at the bottom and is weeping forward in the bottom of the actual casing. I think that all the obvious potential leak points have been checked - flow line, return line, cold water feed to boiler, drain point, pump valves, connections to expansion vessel, auto air vents x 2 and the prv and they are all bone dry. Have I missed any ?

Before the boiler was installed I double checked the heat loss using a software package from one of the central heating organisations so as to be sure that the boiler was the correct size.

I have purchased an inspection camera to see if we can identify the source of the leak.

If it is a bad weld rather than corrosion perhaps it can be repaired ?

At this stage I am assuming it is a new boiler as I doubt that it is cost effective to replace the actual water jacket ? Would you agree ?

I look forward to hearing from you.

 

[oilhead]

I'd put the cost of an inspection camera towards a new boiler.

 

[WhatNext]

Thanks Oilhead ..... I guess that says it all