Thermo-hydraulic performance of PHE in Z-type flow arrangement under the steady state in four different pass arrangements 1-1, 2-2, 3-3 and 4-4 for both isothermal as well as non-isothermal conditions is experimentally investigated. This work is reported for Reynolds number, Re = 330-2850 and Prandtl number, Pr = 4.5-5.0. The present experimental investigation is carried out for mass flow rate, m = 0.63 1.35 kg/s, volume flow rate same for both hot and cold fluid, V = 2000-5000 LPH and mixed chevron angle for chevron plates (30 degrees and 60 degrees plates alternatively). Multi-pass arrangements are made for the equal number of pass for both hot and cold fluids with counter flow arrangements. The present study brings about the effect of an increasing number of pass on the thermo-hydraulic behaviour of PHE. The results show that with a high number of the pass, increase in velocity may be counterproductive in terms of effectiveness and Nusselt number enhancement at the same mass flow rate condition. However, for the same NTU condition higher number of pass brings to decrement in the effectiveness of PHEs. On the basis of experimental data, correlations have been proposed for Nusselt number, effectiveness and friction factor individually for each 1-1, 2-2, 3-3 and 4-4 pass arrangements of PHE.