Vaillant combi boiler

[bronski2]

I have a Vaillant combi boiler that has 2 gauges on it. One is a temperature gauge which has constantly been zero since i moved in and the other is a pressure gauge which varies from below zero on the pin and below zero just above the pin. The heating works fine but lately the hot water has been temperamental and now does not switch on. Is this a pressure problem and if so how do i adjust it? There are a number of pipes going into the base of the boiler but turning the screw on the water pipes does not seem to increase the pressure on the gauge.

[gucciman]

your question isn't making a lot of sense, especially with regards to the pressure guage.

firstly, if your heating is working fine but your temp guage is reading zero then you need a new temperature guage.

the pressure guage on a vaillant should be 1.2 bar. there should be a filling loop below the boiler going from the 15mm cold feed to the 22mm return heating pipe. the filling loop is normally silver and flexible and may have 1 or 2 taps on it. both taps need to be open to fill the boiler to 1.2

your problem with the water is probably due to a defective diverter valve and it will need replacing.