SWEP DP310

Start with what is still legible. The model and the plate count after the x are the fields that matter most, and a partial read of either narrows the search. The unit may read DP310 or DPD310 - both are this model.

Failing that, measure. The footprint should be 525 x 243 mm. Record the plate pack depth, and the type, size and position of each connection. Be careful with the conclusion, because the DP300 and DB300 have the same footprint. The chiller's model and serial number are the tiebreaker, so include them.

Threaded, Victaulic and solder are the three catalogued. Refrigerant circuits are brazed in through solder connections; the water side is threaded or grooved.

When matching existing pipework, get the size and the method for each port, and note which face each one is on. A solder size followed by U is a universal connection that takes both imperial and metric tube. For grooved water connections, the groove size on the unit must match the couplings already on the pipe.

All three are 525 x 243 mm with a published maximum flow of 264.17 GPM. The DP300 and DB300 are the AsyMatrix pair - evaporator and condenser - built for low water pressure drop, and the DP300 datasheet lists 304 plates.

The DP310 has 316/316L plates, takes up to 350 plates against 346 on the 300 models, and is published at up to 49 bar (710 psi). It is the one aimed at refrigerant-side performence. The plain B56 on this footprint carries 335.5 GPM and is not a dual unit.

An undersized evaporator runs a low suction pressure for the load. The evaporating temperture has to fall to drive the heat across too little surface, capacity and efficiency fall with it, and the low-pressure or freeze protection trips on cold days.

An oversized one is harder to spot. Channel velocity on the refrigerant side is low, most of all when only one circuit runs, so superheat wanders and oil can hang up in the unit.

Neither is cured by adjusting the expansion valve. The configurations on file run from 50 to 220 plates; match the original count.

It is an evaporator for two-circuit chillers and heat pumps, intended for systems where refrigerant-side performance and a pressure rating of up to 49 bar matter.

Do not use it on a single-circuit machine, as a condenser, or where the chilled water pump has little head to spare and the original unit was a DP300. With copper braze it is also unsuitable for ammonia and for deionized water. And 49 bar is short of what CO2 systems call for; those use the U class, which starts at 64 bar.

Check the field after the slash in the designation; 1P means single pass. The DP310 configurations on file record model and plate count only, so the nameplate is the authority for your unit.

The practical difference is piping. Single-pass units carry all connections on the front cover. A multi-pass build turns the fluid through the pack more than once for a longer thermal path and a higher pressure drop, and it puts connections on the rear cover too.

These models are catalogued alongside the DP310. Each has its own page with its dimensions, materials and part numbers.

SWEP B56 - SMO 254 high-molybdenum plates - the chloride-resistant frame.

SWEP DB300 - AsyMatrix dual brazed plate condenser with low water pressure drop, 525 x 243 mm, up to 346 plates.

SWEP DP300 - AsyMatrix dual brazed plate evaporator with low water pressure drop, 525 x 243 mm, up to 346 plates.