SWEP B86

By never letting water sit still in it while the refrigerant side is cold. Each B86 channel holds only 0.078 dm3, so there is very little water to absorb the cooling and it reaches freezing quickly once flow stops.

Use a flow switch or differential-pressure proof interlocked with the compressor, a low-temperature cutout on the leaving water, and pump overrun at shutdown. Add glycol for the lowest temperature the loop can see. On channels this tight glycol adds noticeably to pressure drop, so recheck the pump. The strainer is part of freeze protection here: a blinded strainer is the usual reason flow stops. More at Freeze Protection.

Upright, with the 526 mm dimension vertical, and with the two fluids running counter-current - one entering at the top on its side, the other at the bottom. Counter-current piping is what delivers the close approach this frame is selected for. Piped co-current, the same unit falls well short and looks undersized.

On refrigerant duty, vertical mounting is not optional, because liquid distribution relies on it. Support the pipework within a short distance of the unit. The catalogued 1" and 22U combo connections accept either a threaded fitting or a soldered tube, and neither is meant to carry pipe weight or compressor vibration.

The particles lodge at the channel entries and stay there. A brazed pack cannot be opened, so anything that will not dissolve or back-flush out is permanent.

The effect is uneven. Blocked channels stop carrying flow while their neighbors run faster, so total pressure drop rises and effective surface falls. On an evaporator the stalled channels are the ones that freeze. Fit a strainer on every water inlet.

M is the pressure class, and every catalogued B86 on file carries it, as in B86Hx60/1P-SC-M. The class covers up to 45 bar at 135 C and is fatigue tested, which is why it is the usual choice for R410A-type refrigerant circuits that cycle on and off for years.

Read it as a category. The design pressure and temperature stamped on the unit are what the relief device and the system test pressure must be set against, and those can differ from the class headline. Pressure Classes compares the letters.

At 0.078 dm3 per channel, the B86 holds less fluid per plate than any other frame on the 526 x 119 mm outline. On the refrigerant side that means a low charge for the surface provided, which helps on systems where charge is limited or expensive.

The trade-off is on the control side. With so little fluid in the pack the outlet temperature follows a load change almost at once, which is good for response and hard on a slow or oversized control valve. If an expansion valve hunts after a B86 replaces a larger-volume unit, look at the valve sizing and tuning before blaming the exchanger.