Heating system keeps losing pressure

[stratplus]

Can anyone add to this list of possibilities:
Leak on rads valves etc
Leak on pipework
Leak on air vents manual and auto
Expansion vessel lost charge
Prv passing
Plate hx leaking on primary side

Anything other than the obvious.
If plate hx was mixing with incoming cold the pressure would be higher on gauge and Prv would be constantly passing so no pressure lost .....right?

 

[ShaunCorbs]

hex leaking internally and dripping down condense

 

[Harvest Fields]

Leaks on rubber hoses on Vaillant’s

What boiler is it?

 

[stratplus]

Leaks on rubber hoses on Vaillant’s

What boiler is it?

Ideal Isar

 

[stratplus]

hex leaking internally and dripping down condense

Interesting, can you explain that one in more detail Shaun please.
To my knowledge the hx has four ports:
Primary F and R
Cold in and hot out
Condense collected from flue gases
How would you lose heating water/mains water through condense?

Ok, you mean main hx not plate.
Still lost though.

 

[ShaunCorbs]

Yes main hex

Would be heating water

 

[Darren Jackson]

Main hex could be gone leaking CH contents down the condensate. Is the condensate constantly dripping?

 

[stratplus]

Main hex could be gone leaking CH contents down the condensate. Is the condensate constantly dripping?

Something I’ve never thought of tbh. Worth a look.
Pressure takes a couple of weeks to resch zero from 1 bar. If the main hx was leaking from internally wouldn’t the pressure drop be much quicker?

 

[Harvest Fields]

Something I’ve never thought of tbh. Worth a look.
Pressure takes a couple of weeks to resch zero from 1 bar. If the main hx was leaking from internally wouldn’t the pressure drop be much quicker?

Not necessarily