SWEP SXB16DW

The configuration on file is single-pass: SXB16DWHx40/1P-SC-S 4x3/4". The /1P field is the pass arrangement, and the H before the plate count is the plate type, an obtuse chevron with high heat transfer and high pressure drop.

On a replacement, carry the pass field over unchanged. A multi-pass arrangement sends each fluid through groups of channels in series, which changes both the pressure drop and the connection positions, so it cannot be piped where a single-pass unit sat. If more capacity is needed than a 40-plate unit gives, the frame goes to 140 plates before any other arrangement need be considered.

The SXB16DW and the B16DW are both copper-brazed double-wall units on the same 377 x 119.5 mm face. The SXB16DW adds the Sealix layer on the internal surfaces and is listed at 49.75 GPM maximum flow; the B16DW is listed at 48.4 GPM.

The B16 is the single-wall frame they are derived from: 376 x 119 mm, a 74.41 GPM flow ceiling, and no leak-venting double wall.

So the choice follows two questions - is double-wall separation required, and is the surface protection required. If the nameplate says SX, answer both as yes unless you know why the original was specified. Compare SWEP B16DW and SWEP B16.

Weight follows 1.55 + (0.22 x number of plates) kg. The 40-plate build on file works out to about 10.4 kg (23 lb) dry, and a full 140-plate pack to about 32.4 kg (71 lb).

At those weights the unit needs its own bracket or base; four threaded connections should not be holding it up. Support the pipework independently and close to the unit, and use a backing wrench on each threaded connection so tightening torque does not pass into the braze joint. Mount it where the sides of the plate pack can be inspected, because that is where a leak from the double wall appears.

No - 11.3 m3/h (49.75 GPM) is the ceiling the ports allow, not a design point. A duty rated right at that figure has no margin and usually an uncomfortable pressure drop.

Size from the duty: the flows, temperatures and allowable pressure drop decide the plate count, anywhere up to 140 plates. More plates lower channel pressure drop and tighten the approach, but they do nothing for the loss through the ports. When the flow is near the ceiling, or pressure drop is still too high with a deep pack, the answer is a frame with larger ports or two units in parallel. We will rate both options with the quote.

Keep water from standing in it below freezing. Either locate the unit in a heated space, keep flow and heat on it in cold weather, or drain both sides fully for a shutdown. Neither the double wall nor the Sealix layer gives any protection against ice; expanding ice distorts the plates and the unit is scrap.

Glycol on the non-potable side is common and compatible with the 316/316L plates and copper braze. It protects only the circuit it is in, and it derates the exchanger, since it is more viscous than water. State the glycol type and concentration for sizing.

These models are catalogued alongside the SXB16DW. Each has its own page with its dimensions, materials and part numbers.

SWEP B16 - All-Stainless construction - copper-free plates and brazing throughout.

SWEP B16DW - Double-wall brazed plate heat exchanger on the B16 frame, built for leak detection between circuits.