Boiler pressure shooting up to 4 bar

[Rhys23]

I've been to a boiler that had a ruptured pressure vessel. Replaced the vessel and checked the pressure. All seemed fine then the customer sent a picture of pressure over 4bar again the next day. The pressure relief didn't go off and when I got there it had dropped down to 1.5bar again. The pressure rise is happening when the hot water is on. The pressure relief has since gone off an released the pressure. Any ideas why this could be happening?

 

[KingDoey]

New vessel dodgy? Or customer messing about with filling loop?

 

[townfanjon]

Are you gas safe Rhys ?

 

[Aire]

New vessel dodgy? Or customer messing about with filling loop?

Or filling loop passing

 

[ShaunCorbs]

tube to the vessel blocked?

 

[Scott_D]

What boiler?

 

[Riley]

Open forum?? Gas safe???

 

[ShaunCorbs]

Open forum?? Gas safe???

He’s gas safe

 

[Rhys23]

Yes I'm gas Safe. The boiler is Green Star 24i. The vessel pipe is not blocked, filling loop is not passing

 

[ShaunCorbs]

Plate ?

 

[Aire]

Split in the plate heat ex?

 

[Riley]

But it’s still open forum

 

[Rhys23]

Surely the pressure wouldn't go back down to 1.5 bar after it has cooled down though if it was a split in the plate?

 

[ShaunCorbs]

Surely the pressure wouldn't go back down to 1.5 bar after it has cooled down though if it was a split in the plate?

If it’s dumping out the prv

 

[Rhys23]

Riley, sorry I don't know what open forum means?

 

[Aire]

Surely the pressure wouldn't go back down to 1.5 bar after it has cooled down though if it was a split in the plate?

The pressure dropping back down could be down to the prv opening then re seating. If it's only happening on hot water demand. Are the flow and return valves closed?
Other than that, is the expansion tank undersized?

 

[Rhys23]

It's not always dumping out the prv. The prv was dry when it dropped back down

 

[Aire]

Riley, sorry I don't know what open forum means?

We're not supposed to discuss repairs to gas appliances on the open forum, it should be in the private gas safe section.

 

[Old Account]

Riley, sorry I don't know what open forum means?

He meant we discuss gas related matters on open forum so everyone could read that

 

[Rhys23]

The expansion tank is in the back of the boiler. It had been fine until it ruptured, the new one has enough pressure. Very strange

 

[Rhys23]

Craig Watson. My bad. How do I change that?

 

[Rhys23]

The flow and return valves are open

 

[Aire]

Craig Watson. My bad. How do I change that?

You can't, you need to get the gsr badge so you can gain access to the section. That's down to admin but it isn't a quick process

 

[Rhys23]

Could adding a secondary expansion vessel rectify this issue?

 

[ShaunCorbs]

How big is the system? Rads