Can a combi boiler leak central heating water from a faulty heat exchanger and get burned off as vapour through the flue

[Rocd372]

Hey, I've pulled the house apart. There is no leak in the system . 2 different plumbers who came to service the ideal 30 said it was working fine. I think that there is a leak in the heat exchanger.

Most Internet info about cracked heat exchangers say that there would be signs of water in the boiler or water coming out of condensation pipe when boiler not running. Neither of these symptoms exist.

I saw in a previous post where someone put perfume into the system and could then smell the perfume coming out the flue vent when the boiler was restarted. From what I gathered, this indicates that there was a fault in the heat exchanger which only leaked when hot.

Is anyone able to confirm if this is a possible scenario which can explain loss of pressure & loosing water but no sign of a leak?

 

[DP]

If the heat exchanger has pin holed heat exchanger, water would be seen dripping from the condensate when boiler off.

Other possibility is weeping radiator valves or fittings.

 

[Rocd372]

Thanks DP. The pressure only drops when the boiler is running. For instance, it can go through most of the summer without needing to top up. There are no leaks in the system. There is nothing coming out of condensate pipe when boiler not running.

Any thoughts on the theory of pin hole leak in primary heat exchanger, which occurs when boiler is running and the leaked water getting burned off?

 

[ETAF]

The pressure only drops when the boiler is running.

is this the problem you are trying to fix - pressure drop
Whats the pressure when system COLD
whats the pressure when system running and HOT

do you have to re-pressurise the system

 

[old duffer]

A hole in the HE would see water coming onto the burner assembly so you would see rust. If you left the burner off for a few hours and checked the burner, you would see water gathered. A pin hole at whatever pressure your mains is will be constant and noticable.

 

[Rocd372]

Hi ETAF, yes the pressure drops gradually over a period of 2 weeks. When it drops too low then boiler errors out to F1. When this happens I have to re-pressurise (top up) the system.

Cold pressure is 1bar
Hot (boiler running) pressure us 1.2

As I mentioned, during the summer months the pressure drops over a few months as the central heating isn't on