SWEP DV200

No, it is the most the ports are published to pass: 27 m3/h. Chilled water flow on a working evaporator is set by the capacity and the temperature drop across the unit, and it normally lands well below the ceiling.

If your design flow comes out close to 118.88 GPM, expect a high water pressure drop and little margin. Adding plates lowers the channel pressure drop but does nothing for the ports. At that point move up to the 400-size dual frame, the DV400, which sits in the 200 to 400 GPM band.

Start with whatever is legible. The model letters and the plate count after the x are the two fields that matter most, and they are often readable when the rest is not.

If nothing is, measure. Height and width should be 525 x 243 mm and the port centres 456 x 174 mm (17.95 x 6.85 in). Measure the depth of the plate pack between the cover plates, note the type and size of every connection and which face it is on, and photograph all of it. The machine's model and serial number help too, because they tie the evaporator to a known build.

It is the single letter after the material code, ahead of the connection list. That letter is a pressure class - a category - and the rating of a particular unit is what is stamped on its plate.

For refrigerant duty the class to expect is M, which covers up to 45 bar at 135 C and is fatigue tested. S covers 31 bar at 155 C. We have no class recorded against the DV200 configurations on file, so read the letter off the nameplate and send it with the request. The classes are laid out under Pressure Classes.

It is right for a chiller or heat pump with two refrigerant circuits and one chilled water circuit, where a single evaporator has to serve both compressors.

It is not right for a single-circuit machine; the 200-size single-circuit evaporators carry 192.41 GPM against the DV200's 118.88 GPM. It is not a condenser - that is the DB200. And with copper braze it is not for ammonia.

Four things. The footprint, 525 x 243 mm. The port centres, 456 x 174 mm. The connections - type, size and position for both refrigerant circuits and the water side. And the depth, which is set by the plate count.

Then check the weight. At 19.25 kg plus 0.42 kg per plate, a 170-plate DV200 is 90.65 kg before it is filled. If the old unit sat on a light bracket or hung partly on its piping, fix that during the change-out. Guidance is under Mounting and Piping.

Too few and the refrigerant has to evaporate colder to move the same heat. Suction pressure drops, the compressors lose capacity and efficiency, and the water side runs nearer to freezing, which is how brazed evaporators get split.

Too many and the opposite problem appears at part load. With one circuit off and the other throttled back, the refrigerant moves slowly through a large number of channels, and superheat becomes hard to hold steady.

The configurations on file run from 50 to 200 plates. Give us the capacity, refrigerant, water flow and temperatures and we will confirm the count.

These models are catalogued alongside the DV200. Each has its own page with its dimensions, materials and part numbers.

SWEP B200T - Dual-over-two-pass on the 525 x 243 mm frame.

SWEP DB200 - True Dual brazed plate condenser for chillers and heat pumps, 525 x 243 mm, up to 202 plates.

SWEP DP200 - True Dual brazed plate evaporator for chillers and heat pumps, 525 x 243 mm, up to 202 plates.

SWEP F200T - A copper-brazed 304 stainless evaporator with solder connections for chillers and heat pumps.

SWEP P200T - Brazed plate evaporator with long thermal length, 525 x 243 mm, up to 250 plates, solder connections.

SWEP V200T - Evaporator on the B200T frame, 525 x 243 mm, up to 250 plates, 192.41 GPM max flow.