SWEP B8LAS

M is the pressure class covering up to 45 bar at 135 C, and it is a fatigue-tested class - the one used for refrigerants such as R410A, where pressure cycles every time a compressor starts and stops. All ten B8LAS part numbers on file are class M.

Treat the class as a category. The design pressure and temperature that apply to your unit are the ones stamped on its nameplate. Do not replace an M unit with an S-class look-alike from the same frame because the dimensions agree: S is the 31 bar category, and the unit would no longer match what the system was designed around.

SWEP's published formula is 0.85 + (0.059 x number of plates) kg. A 30-plate unit is therefore about 2.6 kg (5.8 lb) dry, and a 70-plate unit about 5 kg (11 lb), before the water or refrigerant inside it.

That is light enough that installers hang it from the pipes, and that is the problem. The connections are brazed to a thin cover plate and are not meant to carry the unit, the pipe weight or the thermal growth of the lines. Use a bracket or clamp around the plate pack, support the pipes on their own hangers close to the unit, and isolate it from compressor or pump vibration.

The configurations on file are all single-pass, written /1P in the designation, from 10 to 48 plates.

Single-pass keeps all the connections where a replacement expects them and gives the lowest pressure drop for a given plate count, which fits what this plate is for. Multi-pass arrangements put channel groups in series to lengthen the thermal path; pressure drop rises sharply and the connection layout changes. If a B8LAS cannot reach the required approach, adding plates toward the 70-plate maximum is the first step, well before considering more passes.

Confirm first that fouling is the cause: a rising pressure drop on the water side together with a widening approach points to deposits, while lost capacity with normal pressure drop points elsewhere in the system.

Then clean in place. Circulate a cleaning solution suited to stainless steel and copper through the fouled side, opposite to the normal flow direction, and flush until clear. A strainer ahead of the water inlet prevents most repeat visits, because the narrow channels trap debris that a shell-and-tube would pass.

They share a 17.61 GPM port limit and close to the same outline, so compare what each is for. The B8LAS is 317.7 x 76.2 mm with 316/316L plates and copper braze, built for high thermal performance with low pressure drop. The B8T is 317 x 76 mm. The B8DW, at 318 x 76.5 mm, is a double-wall unit for duties that need leak protection and leak detection.

The E8LAS (316 x 74 mm) and E8AS (315 x 74 mm) are tap water models, and the E8T and BX8T are 315 x 73 mm. See SWEP E8LAS and SWEP B8T for those pages. A few millimetres of width separate them, so identify by nameplate text, never by tape measure.

It is meant for small duties, up to 4 m3/h (17.61 GPM), where a close approach is wanted but the available pump head or allowable pressure drop is limited. That combination normally forces a compromise, and this plate is SWEP's answer to it on the 8-size frame.

Pick something else when the fluid rules out copper braze - ammonia, or deionized water - when potable water regulations call for a double wall, or when the flow is near the port ceiling and the port loss alone uses up the pressure drop budget. In that last case a larger frame is the fix; more plates will not help.

Vertically, with the two fluids in counter-current. Vertical mounting matters most when one side changes phase, and it also lets a water-side unit vent and drain properly.

Because the channels are asymmetric and some builds have unlike ports, the designation's connection field tells you which port is which - connections are listed in port order. Copy the old piping arrangement exactly.

On combo and solder connections, keep heat away from the plate pack when brazing a pipe in: wrap the connection base with a wet cloth and heat the joint, not the exchanger. Then support the lines so nothing hangs on the connections.

These models are catalogued alongside the B8LAS. Each has its own page with its dimensions, materials and part numbers.

SWEP B8T - Nickel-brazed - the copper-free option at small size, for ammonia and aggressive media.

SWEP B8DW - The most compact double-wall brazed plate heat exchanger in the SWEP range.

SWEP BX8T - Compact All-Active brazed plate unit for heat pumps and container refrigeration, to 17.61 GPM.

SWEP E8AS - AsyMatrix brazed plate heat exchanger on the B8T frame, used mainly for heating tap water.

SWEP E8LAS - AsyMatrix brazed plate heat exchanger on the B8T frame for the highest thermal demands in tap water.

SWEP E8T - A compact copper-brazed plate heat exchanger for wall-hung, non-condensing boilers.