( ( ( The ( primary circuit ) ) ( of ( the ( heat exchanger ) ) ) ) ( ( shall ( be ( ( subjected ( to ( a ( leakage test ) ) ) ) ( to ( ensure ( that ( ( polluted air ) ( ( can not ) ( enter ( ( the ( heated air ) ) ( intended ( for ( the ( passenger compartment ) ) ) ) ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NP (DT The) (JJ primary) (NN circuit)) (PP (IN of) (NP (DT the) (NN heat) (NN exchanger)))) (VP (MD shall) (VP (VB be) (VP (VBN subjected) (PP (TO to) (NP (DT a) (JJ leakage) (NN test))) (S (VP (TO to) (VP (VB ensure) (SBAR (IN that) (S (NP (JJ polluted) (NN air)) (VP (MD can) (RB not) (VP (VB enter) (NP (NP (DT the) (VBN heated) (NN air)) (VP (VBN intended) (PP (IN for) (NP (DT the) (NN passenger) (NN compartment))))))))))))))) (. .)))
The primary circuit of the heat exchanger shall be subjected to a leakage test to ensure that polluted air cannot enter the heated air intended for the passenger compartment.
(ROOT (S (NP (JJ Primary) (NNS pollutants)) (VP (VBP enter) (NP (DT the) (NN air)) (ADVP (RB directly))) (. .)))