Two unregistered gas fitters and a registered gas engineer have been jointly prosecuted for safety failings.
Christopher Campbell, 43, of Colchester, installed a new boiler and associated pipework at a house in Colchester during March 2012. A month later, he installed a new boiler at a property on Sovereign Crescent and enlisted the help of Scott Enfield, 25, of Manningtree, to complete the work.
Campbell then asked local Gas Safe registered engineer Daniel Osborne, 31, to review the gas work carried out at both properties in order to obtain signed gas safety records.
Colchester Magistrates' Court heard on 27 March that work at both properties was later classified by gas safety experts as either 'immediately dangerous' or 'at risk'.
An investigation by the Health & Safety Executive (HSE) identified that neither Campbell nor Enfield were registered as qualified and competent to carry out gas work with Gas Safe Register.
In addition, Magistrates were told that despite being a registered engineer, Osborne had provided Gas Safety records for the new boilers at both properties without carrying out the necessary safety checks.
Campbell, trading as Campbell Plumbing & Heating Services, pleaded guilty to breaches of Regulation 3(3) of the Gas Safety (Installation and Use) Regulations 1998. He was fined a total of £1,000 and ordered to pay £2,250 in costs.
Enfield pleaded guilty to a single breach of Regulation 3(3), was fined £500 and ordered to pay £2,113 in costs.
Osborne, trading as Osborne PH Services, pleaded guilty of breaching Section 3(2) of the Heath & Safety at Work etc Act 1974. He was fined £1,500 and ordered to pay £2,187 in costs.
HSE inspector Nicola Jaynes said: "Christopher Campbell and Scott Enfield carried out gas boiler and gas pipe work that was clearly substandard and knowing they were not legally allowed to do so.
"Daniel Osborne failed to identify that gas work had been carried out by unregistered fitters and failed to identify and record the unsafe features at the properties. He then went on to provide incorrect gas safety records.