SWEP DB700

Against the DP700 and DV700 the difference is in the plate, not the outline. All three are 725 x 302 mm with a published maximum of about 555 GPM. The DB700 and DV700 have 304 stainless plates and the DP700 has 316/316L; the DV700 is the AsyMatrix model with asymmetric channels, and the DP700 is described as optimized for high performence in flexible chillers and climate control.

The DB650 is a different footprint: 744.6 x 365.6 mm, about 616 GPM, 316/316L plates, and published as a condenser that also covers single-phase duty. It will not fit where a DB700 was.

By circulating cleaning solution through the water side while the unit stays in the machine. The pack is brazed solid and cannot be taken apart, so there is no mechanical cleaning.

Two points are specific to this construction. The cleaning chemical has to be safe for copper as well as for 304 stainless - an acid that is too strong or left in too long attacks the braze. And prevention is cheaper than cleaning: a strainer on the water inlet keeps debris out of channels that cannot be reached afterward. Loss of capacity together with a higher water-side pressure drop is the usual sign that cleaning is due. See Cleaning in Place.

The outline is 725 x 302 mm (28.54 x 11.89 in) and the port centres are 546 x 191 mm (21.50 x 7.52 in). Check both - the port centres are what the pipework was built to.

Depth is not fixed. The model takes up to 362 plates and the part numbers on file span 50 to 220, so measure the pack depth on the old unit or count its plates. Then confirm the type and size of each connection.

Usually enough. The designation is one line, and even a fragment helps: the characters before the x give the model, the number after it the plate count, and the letters after the dash the material code and pressure class. A wire brush and a rubbing with pencil and paper often bring up stamped characters that cannot be read by eye.

Where the model line is gone, dimensions narrow it to the 725 x 302 mm group and no further - the DB700, DP700 and DV700 are identical in outline. The chiller's own model and serial number, or the original submittal, then settles which of the three it is.

Clean, treated water, glycol solutions and the common refrigerants. 304 plates with copper braze is the construction SWEP codes NC, intended for ordinary water at lower cost than 316.

It is unsuitable in three situations. Ammonia attacks copper braze. Deionized or ultrapure water leaches copper. And chloride-bearing water - chlorinated, brackish or sea water - pits stainless plates; that service calls for SMO 254, and 304 has less margin than 316 to begin with. If the water loop is open or the chloride level is unknown, get an analysis before choosing this model. Plate and Brazing Materials sets out the alternatives.

These models are catalogued alongside the DB700. Each has its own page with its dimensions, materials and part numbers.

SWEP B427 - 420 plates, dual circuit, 685 GPM.

SWEP DB650 - True Dual brazed plate condenser, 744.6 x 365.6 mm, up to 346 plates, 140 m3/h maximum flow.

SWEP DP700 - True Dual brazed plate evaporator, 725 x 302 mm, 316/316L plates, up to 362 plates.

SWEP DV700 - True Dual AsyMatrix brazed plate heat exchanger, 725 x 302 mm, 304 plates, up to 362 plates.