Shares in the speculative heating and air-conditioning equipment play have traded up to a 52-week high of 11.25p (against a 2.5p low) following last year's restructuring bout. Investor appetite for the stock has been aroused following a recent letter of intent for a potential joint venture with private firm Suvair. The deal would aim to fashion a filtration system that eliminates dangerous bacteria, moulds and viruses - mainly for use in hospitals and clinics. Only last month the group cheered followers with a 78% underlying profits rise for the year to March. Pre-tax profits hit £365,000, on continuing sales up 4% to £11.7m. Borrowings fell by £655,000 to £1.1m. The firm returned to solid profitability following the disposal of its last loss-making business, Benson Heating, in summer 2001. After the disposal, the balance sheet was re-capitalised through a share issue to a new investment consortium, raising £1.1m.