Boiler deemed dangerous by one plumber but safe by another

If the appliance were classified as ID (Immediately Dangerous) then the Gas Safe engineer has a responsibility to make safe the appliance before leaving the property or ensure that National Grid are notified and they will in turn take appropriate action if necessary. The combustion reading you have stated seems to be the CO level. When we carry out a gas flue analyser test on a boiler, one of the final determining factors to establish if the boiler is safe and preforming properly is the CO/CO2 ratio. Generally when this level is below 0.004 the boiler is considered to be running efficiently. When between 0.004 and 0.008 this indicates a potential problem and investigation and retesting must take place. When above 0.008 the appliance must be fully investigated, cleaned and retested. NB: If the CO level in the flue of a gas appliance is above 100ppm (parts per million) then an investigation must take place, as seems to be the case. But very rarely is a boiler classified as ID if it fails a gas flue analyser test and then at the very most is would be classed as 'At Risk' unless incomplete combustion or spillage is occurring which is a ID classification. So therefore your engineer was correct but should have made the boiler safe! AS STATED, IF YOUR ENGINEER HAS FOUND THE BOILER TO BE UNSAFE THEN HE HAS A LEGAL OBLIGATION TO MAKE IT SAFE!

Very simple really, it's likely to be a bogus/fake certificate! I regularly get asked by landlords and homeowners to issue electrical certificates to state that the wiring is safe, when it's clearly unsafe. It's the same for gas certs. I've been offered significant sums of money, but integrity is more important. I would go with what your original plumber has said. It sounds like he is more qualified and up to speed with current requirements. At 20 years old boiler is almost at the end of its life, so it will need to be replaced in the next few years even if it was safe. Try and seek a reduction in the price agreed on the house. If the buyer won't negotiate then best to pull out and walk away and find another property. In addition if you have not already had one carried out, it's well worth getting a full Electrical Installation Condition Report carried out on the wiring, as around 80% of older properties have unsafe/defective wiring.