Boiler help/advice

[DP]

Isolation valves.
Recently had to isolate said valves under my Vaillant Ecotec plus 832 to remove a radiator from the system.
Used Allen key to turn the spindle quarter turn with some difficulty. After the radiator was drained and removed, pipes capped, when I returned to the boiler, pressure was at zero as the isolating valves did not isolate way they do when new

Stuckinarut is a fellow gas engineer and a pro with vast knowledge of the gas appliances.

 

[mole81]

So here's some pics, f22 again this morning, then initial top up pressure and after running heating for 15 mins so a slight increase?

 

[Stuckinarut]

If that's the pressure after about 10 minutes then the expansion vessel is pretty much ruled out - but worth getting it checked

 

[Stuckinarut]

View attachment 375420picture of a leaking heat exchanger in vailant ecotec.

Eventually he will have to open to confirm if it's leaking or not.

To be pedantic that's inside the combustion chamber with the burner removed showing a leaking heat exchanger but I get what you're saying

 

[mole81]

If that's the pressure after about 10 minutes then the expansion vessel is pretty much ruled out - but worth getting it checked

Thanks that's one off the list at least then (it was after 15 mins too)

 

[Stuckinarut]

If it's dropping daily then isolating the flow and return might be best done first thing in the morning, about 08:00 and open back up at about 16:00. If the pressure has dropped you know it's at the boiler/main heat exchanger

 

[mole81]

Ok I'll arrange this test and report back

 

[mole81]

Flow and return have now been isolated, now I hope the pressure drops to rule out pipework!

Question, if the main heat exchanger is leaking, would only using hot water still cause it to expand as guess there's a smaller heat exchanger for hot water too in these vailants?

 

[kidgreen61]

Because the mains pressure is higher than system pressure, a plate heat exchanger leaking internally would indeed cause the pressure to increase.

 

[mole81]

Because the mains pressure is higher than system pressure, a plate heat exchanger leaking internally would indeed cause the pressure to increase.

It's not increasing it's losing pressure

 

[Stuckinarut]

If the main heat exchanger is leaking, expansion doesn't really play a part other than normal expansion. It disappears down the condensate connection

 

[mole81]

Lost .2 bar overnight after isolation, will give a few more days and monitor

 

[mole81]

Been 4 days now and not really lost any pressure. If main heat exchanger was leaking would using hot water alone cause it to expand and leak still or would that not be the case?