SWEP B649

It means the unit holds a lot of fluid. Each channel carries 1.18 dm3, and roughly half the channels in the pack belong to each circuit.

So the operating weight is well above the dry figure from the weight formula, the outlet temperature lags behind valve movements, and any inhibitor or glycol dose has to include the exchanger volume - negligible on small frames, not here.

As a piece of plant, not as a pipe fitting. The formula is 61.58 kg plus 1.941 kg per plate (135.76 lb plus 4.279 lb per plate), so even the 220-plate build on file is about 489 kg (1,077 lb) empty.

It stands on its own base on a structural frame or plinth sized for the filled weight. Lift it with rated gear from the points intended for it, never by the connections, and keep the pack upright through the move. Decide before delivery how it gets into the plant room and how it would come out again, because at 1232 mm tall and 537 mm wide the route is often what limits the plate count that can be installed.

SWEP lists two: flange and combo. There are no threaded or solder versions at this size. A combo connection accepts two joining methods or sizes on the one port, which gives some latitude where the existing joint is not what the drawings show.

The strings on file for the B649 give only frame and plate count, so the connection is something to specify. State the flange size and standard on the existing headers and the pressure rating of the system. A mismatch between flange standards is the usual surprise on site: the bolt circle does not line up, and it is found with the unit already hanging from the crane.

The depth available and the header spacing in both directions. Port centres are 995 mm vertically and 300 mm horizontally (39.17 x 11.81 in), and those are fixed. The depth is not: the pack grows with every plate, so a replacement with more plates than the original pushes the rear face back and may foul a wall, a support or back-side pipework.

Measure clearance behind and in front of the unit, the height of the lower ports above the floor, and the flange faces relative to the headers. Where the new unit has a different plate count, allow spool pieces or adjustable supports instead of expecting the old pipework to meet it exactly.

Four things: the plate mix, the plate count, the material code and the pressure class. The published example is B649L+M/1P-NC-Y, a mixed pack of L and M plates, single pass, in NC - AISI 304 plates with copper braze.

The plate count can be counted on the pack edge. The material code matters because 304 is chosen for ordinary water; if the water chemistry has changed since the unit was installed, say so. The class letter Y carries no published category figure, so the rating has to come from the stamped pressure and temperature. Send us a photo of the label and the article number if it survives, and we will confirm the rest.

Piping direction matters a great deal. Run the two streams counter-current, entering at opposite ends of the 995 mm plate length. That long plate exists to hold a close approach, and co-current piping throws the advantage away while everything still appears to work.

Install it upright. The connections should carry no external load: support and anchor the headers on their own steel, allow for their thermal expansion, and isolate the unit from pump vibration and from water hammer caused by fast-closing valves. Repeated pressure shocks fatigue braze joints, and on a network this size slow valve actuation is the cheap protection. Mounting and Piping has the detail.