THE wife of a former Ulster Unionist MLA uses an RHI boiler for a "horse solarium".
Neil Somerville said his wife runs the family business 'Clogher Valley Horses Welcome' and uses a wood pellet boiler as part of the Renewable Heat Incentive (RHI) scheme.
The party had asked all its elected representatives last month if they had directly benefited from the botched scheme which could cost taxpayers up to £490 million.
Names of all claimaints are due to be published by the Department for Economy tomorrow.
A UUP spokesman said many who applied feel they have been "unfairly vilified because of a catastrophic failure with the Department of Enterprise Trade & Investment".
It also said it had asked energy regulator Ofgem to "fast track" an audit of the Somervilles' boiler "alongside those belonging to relatives of elected representatives".
"That is only fair, and the best way to ensure public confidence," he said.
Mr Somerville, who was an MLA in Fermanagh and South Tyrone for seven months before standing down due to stress in January last year, said he wanted to be "open and transparent" about his family's interest in the scheme.
"My wife runs the business which also includes the grooming and clipping of horses, but due to the type of work she does, it wasn't possible to carry it out all year round," he said.
"We inquired about a wood pellet boiler in July 2015 and a 99kW boiler was installed in August 2015. The installation of the wood pellet boiler has meant that my wife is now able to carry out her work on a year-round basis and a horse solarium has been installed. We are happy for an inspection to take place."
The party also said it had also been made aware that relatives of Ulster Unionist MLA Sandra Overend have benefited from the RHI scheme.
An aunt and uncle of Mrs Overend, who run a business, were recipients of the subsidy.
The party said Mrs Overend was "previously unaware" of the information.
Her aunt is also a sister of Ulster Unionist MEP Jim Nicholson.
Meanwhile, the north's biggest wood pellets manufacturer has confirmed it shared information about proposed changes to the RHI tariff months before they were officially announced.
Balcas, based in Ballinamallard, Co Fermanagh, said there was "nothing sinister" in the move and it did not know the information was confidential.
Last week, Dr Andrew McCormick, Permanent Secretary of the Department for the Economy, said "premature information" had been released to the renewables industry about the planned changes.
He said it may have had a significant impact on the £490m overspend.
