SWEP SXB28

It is designed for water-to-water heating duty across a range of capacities: district heating substations, radiator circuits and tap water heating, on water that scales or is hard on the metal.

It is the wrong exchanger where the fluid needs a different metallurgy, not a coating. Ammonia attacks copper braze. Deionized water calls for a copper-free construction. Chloride-bearing water such as pool or brackish water pits 316 and wants SMO 254. It is also the wrong frame once the duty needs more than 74.41 GPM through the ports. And if the specification names a particular potable-water approval, state it in the quote request so we can confirm it.

Heating water, tap water and water-glycol mixes are what this combination is for: 316/316L plates and copper braze, with the SiO2-based Sealix layer on every inner surface to resist scaling, corrosion and metal release.

The layer does not change the underlying construction, so the usual copper-braze exclusions still apply. For the full comparison of codes see Plate and Brazing Materials. When describing the water for a quote, give hardness and chloride level if they are known - those two numbers decide whether Sealix is the right answer or a different material code is.

SWEP publishes threaded connections for this model. There are no catalogued SXB28 part numbers on file, so thread size is set with the order.

On a replacement, match three things: the thread size at each port, the thread standard, and the 470 x 63 mm port centres. A thread that is nearly right will start and then leak or gall. If the existing pipework is soldered or flanged, plan for unions or adapters instead of forcing the pipe to the new unit, and when tightening, hold the connection with a second wrench so the torque does not go into the braze joint.

No. The layer slows scaling; it does not make hard water soft. A tap water heater running hot on hard water will still collect deposit, more slowly.

Cleaning is done in place, since the unit is brazed and cannot be opened: circulate a cleaning solution through the affected side, against the normal flow direction if the pipework allows, and rinse well. Tell us what cleaner the site uses so we can confirm it suits the unit. Rising pressure drop and a falling tap water outlet temperature at the same primary flow are the signs it is due. See Cleaning in Place.

By SWEP's formula a 60-plate SXB28 weighs about 11.9 kg (26.3 lb) empty, and a full 140-plate unit about 25 kg (55.3 lb). Add the water it holds.

A substation unit this size belongs on a wall bracket or a foot, not hanging between four threaded pipes. Threaded connections are the least forgiving of side load: pipework that is sprung into place or left unsupported bends the connection at its root, and the leak appears months later at the braze joint. Support each pipe run close to the exchanger and allow for thermal expansion of the hot lines.

Only if the duty needs it. SWEP's example designation is single-pass, SXB28H/1P-SC-S: each fluid crosses the plates once and all four ports are on the front cover.

A multi-pass arrangement gives a longer thermal path, which helps when a large temperature change or a very close approach is needed. It costs pressure drop on that side and moves some connections to the rear cover, so an existing single-pass installation would need its pipework changed. Adding plates, up to the 140 this frame allows, is usually the simpler route to a closer approach.

These models are catalogued alongside the SXB28. Each has its own page with its dimensions, materials and part numbers.

SWEP B28 - Two-pass series arrangement on the 526 mm frame.