Go to the back and check the temp (with your hand, carefully) on the heating (generator) section and the absorber coils ( the section in the lower middle that has the tubes running diagonally). They should both feel about the same temp. If not, like one is noticeably different than the other, you might have a blockage in the cooling unit.
Also, have you cleaned the flue recently. A rusty or semi-clogged chimney area and the spiral baffle that is suspended inside should be cleaned AT LEAST yearly to facilitate the heat transfer to the refrigerant.
Solar Tech Energy Systems, Inc.
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