EV Pressure on Junior 28i

If its just been fitted and not working get him back, do not touch it yourself as that would invalidate any warranty you may have

 

As Dave says.

(But, for your info, they are normally pre-pressurised to around 0.75bar, perhaps up to 1 bar. The important point, however, is - the air side should be pressurised to this level when the water side is at zero, or before it's actually fitted. If the water side has any pressure, that will affect the air side's readings. Even if the water side reads '0', it still acts as a firm water barrier so could have an effect. Ideally, a radiator bleed screw should be opened until it stops flowing, and then left open as the air side it pressurised - more water should be ejaculated as this happens, keeping it at a genuine zero.)

 

Sludge in a system is guilty of many crimes against boilers, but I can't see it being responsible here. Sometimes sludge will block the narrow pipe to a pressure gauge, giving a false reading, but that usually means it reads low.

And, you said that you checked the air pressure in the new exp vess, and it read zero - that's an exp vess that hasn't been set up properly.

Is the boiler's gauge a digital or analogue one?

These fluctuating pressures you mention, when exactly do they happen? Is it when you turn on the rads, for example?

And are you 100% certain you haven't left the top-up tap partially open?

 

Does the presssure ever drop quite low and need topped up?
Why was the additional vessel fitted? Was it because the pressure was simply rising or was it rising then dropping, and requiring topped up with pressure.
If not it could be a passing filling loop or leaking DHW heat exchanger causing the pressure to continuously rise.

 

Caused a drip? Where? Out your safety discharge pipe?

Let's hope your PRV has closed properly - usually, once opened, they don't close fully, so allow the system to lose pressure over time - very annoying.

Anyhoo, I'm not a plumber but some info is chust so available that most peeps - like me - have an inkling of what's involved. And I'd surmise that your plumber is a twit.

Remote EVs should ideally be fitted on a system where they cannot be affected by valves and stuff, so that usually means on the return. I cannot see any way fitting it on the flow will help.

Here's an example info vid -

He reckons his EV was pre-charged to 1.5bar, which I thought was high. But what the hell do I know.

A trick often described on this forum when an EV blows is to drain half a radiator - and that effectively becomes an EV.

Anyhoo, not sure what to suggest about your plumber - I guess it doesn't matter too much what he does as long as (a) he fixes it as he should and (b) doesn't charge any more money for it.

Because he shouldn't charge you any more for not fixing something he should have...

 

Let us know what he does to sort this - it's an interesting one.

If the original one was full of water, then obviously the diaphragm inside had burst and it was no longer working.

The symptom of this is roughly as you say; the pressure would rise dramatically as the system heats up and the sealed & heated system water has nowhere to expand to. As the system cools down, the pressure should also drop right down - possibly below what it was originally because sometimes some water is expelled out the PRV when it's at max pressure.

What should NOT happen is that the pressure falls to a higher-than-original level when it cools down (not unless you've been topping it up).