Kulwinder Bola who runs the Royal Hotel in Drummond Road, Skegness, was found guilty at Skegness Magistrates Court of breaching the notice issued by Health and Safety Executive inspectors.
He was also found guilty of not using CORGI registered contractors to install gas pipework and gas catering appliances in the hotel's kitchen and failing to employ a planning supervisor to oversee the renovations.
For ignoring the prohibition notice Mr Bola received a 12-week custodial sentence, suspended for one year and an order to carry out 200 hours of community service within the year. He was also told to pay the full court costs of £20,623.
Mr Bola received a conditional discharge for the other two charges.
The Health and Safety Executive prosecuted Mr Bola after inspectors visited the site in July 2006.
Gas equipment 'immediately dangerous'
HSE inspector Judith McNulty-Green said: 'When the inspector visited the hotel on 4 July 2006 a number of items were found to be immediately dangerous, including the gas supply to appliances.
“Four appliances were fitted with flues and required extraction but no extraction system was operational. Due to the danger of carbon monoxide, those appliances were disconnected from the gas supply and a prohibition notice was served banning their use.
'However, the defendant told his chefs they could use the banned equipment.
'HSE takes very seriously breaches of notices. Ignoring the ban was extremely dangerous and posed a serious risk to employees at the hotel.
“I agree with District Judge Blake's comments that notices are issued to keep people and places safe and this sentence sends out an important message.'
Gas appliances and pipework must be fitted by registered installers
She added: “'It is extremely important that gas appliances and pipework are installed by a CORGI-registered fitter. Always use a registered fitter.
“It is easy to check if a fitter is registered as there is a free phone number to call or you can check on the CORGI website.
“Never be tempted to cut corners or save money - you will be putting your health, or even your life, at risk. Every year 20 people lose their lives from carbon monoxide poisoning.”
Mr Bola was found guilty of breaching Regulation 6 (1) of the Construction (Design and Management) Regulations 1994; Regulation 4 of the Gas Safety (Installation and Use) Regulations 1998; and section 22 of the Health & Safety at Work etc Act 1974.
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