Losing Pressure, Sealed System, Check List

[Diyisfun]

There are lots of post on here about losing pressure from sealed systems, what I was wondering is, is there a check list that you plumbers go through to work out the most probably cause right through to the most obscure.

My system losses pressure & I accept that I have to top it up every 2/3 months.

This could be something put on as a ‘sticky’

 

[Gasguru]

Check easiest things first:

Boiler auto air vent - often slight leak (if within combustion chamber the water will often evaporate off - Corgi job)

Boiler heat exchanger

Boiler safety release valve

General pipework leaks on boiler - some boilers are very incontinent eg. Ocean FF, Saunier Duvals,

Isolating valves on boiler

Radiator valve spindles - especially all non BS2767 Pt10 valves ie most valves fitted round my patch.

Thermostatic valve spindles (remove heads to check)

Valve connections to radiators/pipework

Zone valve spindles

Any other valves (bypass/lockshield/ballofix especially)

All visible pipework/joints

Expansion vessel gradually losing air pressure (quality vessels will hold their pressure over a few years, some however may require significant inflating every year). Vessel should be re-charged to correct pressure and re-checked at a later date - perhaps 3 months later. You can then get some idea of pressure loss.

All invisible pipework/joints ie rip up floor etc

Pipework may have to be isolated in sections to find leak.
Suspect pipework if joints covered in snot.
If a sealed system wind up pressure to just below 3 bar - may help find the leak quicker (don't run the system at this pressure though)

 

[Soggy_weetabix]

AND... air sucked in which will vent through AAV resulting in pressure loss.

Install Fernox Internal Leak Sealant which should seal the leak you have.

David

 

[noonespecial]

My system losses pressure & I accept that I have to top it up every 2/3 months.

It will be a very tiny leak if it causes a problem only every 2 to 3 months.

Never the less it will theoretically reduce the life expectancy of your system and should be sorted.