Worcester 350 combi boiler on but water cold and radiators cold. Have put pressure up but made no difference. What's wrong with it?

You cannot reset pressure in a combi boiler only increase pressure or release pressure!

what are you trying to achieve?

Please contact the manufacturer they will be happy to help.

Try this http://www.worcester-bosch.co.uk/installer/literature/discontinued-product-literature/discontinued-gas-boiler-literature/greenstar-35-he-plus-combi-discontinued-august-2003-literature and select part number
6 720 610 598 download it and follow the instructions. Good luck

Turn the burner back on & make sure you have correct water level in the boiler.

Check the pressure reading, should be about 1 bar when system is cold. Various models in the range of 24cdi. If you do not have a manual, go to,
http://www.centralheating.co.uk/Boiler-Manuals/worcester-bosch-boiler-manuals/worcester-bosch-discontinued-boiler-manuals.
Get the manual for your unit, to wards the end of install manual it has a fault finder, Also has a basic 1 in the user manual. Number of flashes how fast the light flashes which one flashing can all mean different, So get the manual and check, Some parts are easy to fix, as long as you do not touch the gas side the rest is plumbing. Come back if needed.

The boiler has a filling connection which uses a filling loop to connect the boiler to the mains supply for the initial fill and subsequent fills.
See the link below from the manual you can buy the filling loop connection online or ebay its a simple task to replenish the pressure. Worcester GREENSTAR 25Si Instruction Manual Filling The System

Pressure is ok? at 1 bar or above
I think on this one there should be a reset button [red] on the left hand top of the casing - or lower the control panel [ phillips screw on each side] and the button is on the left of the base plate. Press this and try the heating.or hot tap
P.S. if you're on a prepayment meter check you have gas.

check the tops of all your radiator valves for bypass if found, easy to repair best of luck

The first thing you need to do is to put some more water into your heating system. This is usually done by allowing water from your (pressurised) domestic cold water supply to flow into the system: On older boilers, this is done with a connection (often made with a removable hose) on the pipework just outside the boiler. Newer boilers may have a built-in connection with some sort of removable link (sometimes looks like a plastic key).

Once you've got the boiler up to working pressure (typically about 1 bar - 15 psi), you should be able to bleed your upstairs radiator properly.

This may be all it takes, though the pressure excursions you're getting when you run the hot tap suggest there may be another problem. See what happens to the pressure as the boiler heats up and cools down. There really ought to be very little pressure difference between the two conditions. If you see significant changes, this usually means that the "pressure vessel" (or in hydraulic terms, system accumulaor) has lost its air charge.

The pressure vessel is a metal container inside the boiler, usually painted in red enamel. Somewhere near the top, you will find a schrader valve (like the one on a car tyre), and you can use this along with a tyre pump to replenish the air in the top of the vessel. This will reduce your pressure transients for a while, but you need to keep an eye on it. If the problem returns, you probably need to replace the pressure vessel (or clag another one into the plumbing alongside the boiler).

A.

replace pressure release valve