Increasing pressure on Worcester 24i

[Hoxton]

The pressure on the boiler has always been low, below the 1.2 line, but it has functioned fine.
This morning the water pressure on the hot taps has gone down to a trickle.
Presumably I need to top up the pressure by refilling the boiler. I have located the flexi loop below the boiler, but there is only one plastic valve tap, on the right hand side. When you open it, nothing seems to happen. I can't see how to open anything on the other end of the loop, by the water pipe.
I've looked up into the bottom of the boiler, and I don't think I have one of the models where you use the white plastic key - there's nowhere for one to go that I can see.
Very grateful for any help.

 

[dresbo]

I'm not expert and I know this is obvious, but have you checked the water pressure in the cold tap? Do all the hot taps have the same problem? If the cold doesn't work, it's got to be closed stop-cock, a leaking supply, or problem at the water company.

The pressure listed on the front of the boiler is usually the heating system pressure (esp. if it reads around 1bar), which, presuming you have a sealed system (since you have a filling loop) fills up using the cold supply, using the loop, to the pressure you want. If this pressure is too low, the boiler will not fire, but you will (at least on my boiler) get lots of cold water through the tap as the water circuits are completely independent unless the filling loop is open. The pressure in this circuit is driven by the cold supply water pressure.

If the filling loop genuinely doesn't fill the heating and you've opened it all up, maybe there's a leak in the pipe somewhere causing low pressure, or perhaps you inadvertently partially stopped off one of the valves in the line from the cold supply to the tap. On mine, at least, there is one on the very bottom of the boiler, one on the line just after the boiler, one before the boiler to stop of the supply to the house completely and one just below the tap.

Others may confirm whether this is possible, but my last thought is that perhaps your boiler is unable to supply the water at that heat quickly enough (due to some problem with the boiler) and has some sort of restrictor to restrict the flow rate when the water is coming out too cold?

 

[Hoxton]

Thanks for the reply. Yes, it was only the hot water that lost pressure, but I think that must have been down to the builders working outside, messing with the mains or something. Seems ok since. But yes realise now I'm mixing up water and water pressure with central heating.

Finally worked out that while there's one valve on the flexi loop by the boiler, the other valve for the cold water is actually under the kitchen sink! Once I opened that I could fill the boiler with the flexi loop and the pressure is back up to 1.2