Had my boiler serviced on 17th April Had my boiler serviced on 17th April. Everything absolutely fine and we received a certificate by email to this effect. We reported loss of pressure. Engineer advised a screw had disintegrated so he replaced it. Pressure still dropping so back he comes and advises we need a new pump but this would need to be fitted by Vailliant Enginee. Said engineer called out yesterday and advised our heat exchanger was badly corroded and had been for some time judging by the corrosion marks. Gas emitting at a dangerous level from back of heat exchanger so immediately dangerous. Corgi really couldn’t care less so we are without hot water and heating for the second day and we care for a disabled and vulnerable adult. Legal advice will be taken but please proceed with extreme caution.