Boiler losing pressure (no leaks in pipework)

[Jonh57]

Boiler is a Greenstar 30CDi combi. Last week the pressure dropped to 0. After filling boiler up to 1.5bar it will drop to 0 bar in less than 6-7 minutes. Went under the floorboard and checked all piping, no signs of leak.
Eventually I found the condensate pipe is discharging glugs of water with the boiler switched off.
Anyone know what the cause could be, losing that amount of water so fast??

 

[picasso]

The main heat exchanger has a hole in it, how old is your boiler ? it may still be under warranty.

 

[Jonh57]

The main heat exchanger has a hole in it, how old is your boiler ? it may still be under warranty.

It has a manufacturer date of August 2008, I think it was bought early 2009. If it was the heat exchanger, would it leak that fast. It is losing around half a cup of water every 6-7 seconds, the boiler is completely empty after 5 minutes.

Something else that might be of relevance. There is a magnaclean fitted under the boiler , I was told that turning off the two valves connecting to the Magnaclean would isolate the boiler. I tried it after filling the boiler to 1 bar and it does not leak after doing this.
Would the condensate pipe still leak with the boiler isolated if the heat exchanger was leaking?

 

[Jajodu]

primary heat exchanger leaking would give those symptoms.

 

[Madrab]

As the other chaps have intimated, really only a hole in the Primary Hex would give you that symptom of water constantly running out of the condensate until the boiler empties and reads 0 on the gauge. Does the pressure on the boiler gauge stay at 1 bar when you isolate the valves around the filter?? if so then there's something really weird going on.

 

[Jonh57]

Just to check, this symptom wouldn't be caused by the secondary heat exchanger? This part: https://www.plumbcenter.co.uk/product/worcester-bosch-87161082120-heat-exchanger-20-plates.

Over the last week I have actually been using the boiler with the main water refill constantly on slightly, to balance out the water loss and keep it at around 1 bar. The boiler actually works normally doing that with the central heating and hot water.

 

[FiremanT]

Is it a Logic?

 

[picasso]

I wonder if the op is confusing the prv outlet with the condensate pipe ?

 

[Jonh57]

I wonder if the op is confusing the prv outlet with the condensate pipe ?

It is definitely the condensate pipe. I put a balloon around the smaller copper prv outlet and nothing came out over 3 days.

 

[Madrab]

Just to check, this symptom wouldn't be caused by the secondary heat exchanger? This part: https://www.plumbcenter.co.uk/product/worcester-bosch-87161082120-heat-exchanger-20-plates.

Nope, that part isn't connected to the condensate, only the primary HEX is.

 

[TicTac]

You could turn off the cold water to the combi to see if it's the secondary heater leaking, but it's unlikely to be. When you turned the magna cleans isolating valves off, it just isolate the magna clean, as the water is still flowing round the other way; in fact, depending on the model, it may not be doing a damn thing to the boiler flow, so I'm a little surprised over this.

 

[FiremanT]

Is it a Logic?

What boiler?

 

[picasso]

Its probably a 30 cdi combi. (as that's wot he wrote in the first line of his post)