SWEP V26

SWEP publishes a maximum particle size of 0.7 mm for the V26, so the strainer has to stop anything larger. That is finer than many installers assume, and a coarse strainer left from an older exchanger does not protect this one.

In a heat pump the consequence of skipping it is specific. In reverse mode the V26 is an evaporator, and channels partly blocked with debris carry less water, run colder than the rest and can freeze. Fit the strainer on the water inlet, close to the unit, and clean it after the first days of operation when installation debris is still circulating.

SWEP publishes PED, UL and KHK for the V26. The catalogued part numbers on file are pressure class M - a category of up to 45 bar at 135 C, fatigue tested, used for refrigerants such as R410A.

The class letter is a category; the rating stamped on the unit is what an inspector reads. Copy the letter from the old nameplate and tell us the refrigerant.

Yes. Isolate the water side, circulate a cleaning solution through it and rinse - the unit is brazed, so in-place cleaning is the only kind there is. The cleaner must be safe for copper braze as well as the stainless plates.

A heat pump that produces hot water on hard supply water scales on the condenser side of its cycle, and the first sign is a rising condensing pressure at the same water flow. Cleaning at that point is routine. Left until the unit trips on high pressure, the deposit is thick enough that flow through some channels has stopped, and those channels are the ones at risk when the machine reverses.

Not by measuring. Both are 376 x 119 mm with the same flow ceiling, so dimensions, plate count and connections identify the frame but not the model.

Work from the machine instead. A reversible air-to-water heat pump is the application the V26 was built for, and the unit's own model and serial number usually resolve it. The connection pattern helps too: the V26 part numbers on file use 12.8 and 16 solder sizes on the refrigerant side and two 1 in threaded/22U combo connections on the water side. Send photos of all four ports and any remaining label text.

The catalogued V26 designations on file are all single-pass, for example V26Hx44/1P-NC-M. Each fluid makes one trip through the pack and all connections are on the front cover.

That suits a reversible machine. The exchanger has to work with refrigerant flowing in either direction, and a single pass keeps the refrigerant path simple in both modes. A multi-pass arrangement, used elsewhere for a longer thermal path, adds pressure drop and puts connections on the rear cover. On a replacement, the pass code after the slash must match the original.

The frame takes up to 160 plates. The catalogued part numbers on file run from 34 to 74 plates.

More plates give more surface and more parallel channels, so water-side pressure drop falls and the approach tightens, which lowers condensing temperature in heating mode. Each plate adds 0.1105 kg (0.244 lb) and depth. The limit is on the refrigerant side: with too many channels for the capacity, refrigerant velocity per channel drops and reverse-mode evaporation becomes less stable. On a replacement, keep the original count unless the duty has changed. See Plate Count and Capacity.

When the exchanger only ever condenses. The B26 is the high-efficiency condenser the V26 is based on, with the same outline and the same 49.75 GPM maximum flow, and a heating-only machine has no use for the distribution system.

When the machine reverses, the V26 is the one to fit. Its V-ring distribution is there for evaporation in reverse mode, and SWEP publishes that it keeps full condenser efficiency, so nothing is given up in heating. Replace like with like: a V26 for a V26 and a B26 for a B26.

These models are catalogued alongside the V26. Each has its own page with its dimensions, materials and part numbers.

SWEP B26 - Asymmetric channels - two different channel volumes in one pack.