Installation / Operation Instruction Manual

BLP SERIES Install, Operation, and Maintenance Manual
SECTION 3: OPERATION AND CONTROLS
Rev-1 Bradford White • 200 Lafayette St. • Middleville, MI 49333 Page 21 of 83
BrutePlate Manual Phone: [phone] • Website: www.BradfordWhite.com 02/26/2020
Glue type gaskets: The surfaces of these gaskets need to be clean and free of oil. Use only
chloride free glues, such as Pliobond 20 or 30, Bostic 1782, 3M EC 1099, and Bond Spray 77.
Follow the manufacturer’s instructions printed on the cover of the glue.
CAUTION!
When using commercial solvents and adhesives, follow the manufacturer’s recommendations
carefully, as many of these materials are hazardous.
O-rings: Make sure that the flat side of the O-ring fits into the special packing groove of the
plate. If the O-ring is not provided with a flat side, the thinnest side of the O-ring needs to be
fitted into the groove. It might be necessary to use a little glue for positioning the O-ring during
assembly of the heat exchanger.
Rubber liners: On some model types, the rubber frame plate nozzle liners have an O-ring molded into
the liner itself. This molded O-ring fits into the gasket groove in the first plate. Therefore, if new gaskets
have been fitted, the O-ring portion of the gasket around the nozzle hole will have to be cut off prior to
assembly back into the frame.
3.3 Construction and Performance
BLP Series units are Double-wall construction heat exchangers which features boiler and
domestic water separated by an air gap between two walls, rather than being separated by
only a single wall. This greatly enhances protection against leakage of the boiler water
into the domestic water. If there is leakage in a wall, the water is collected within the air gap
which is vented to atmosphere for leak detection. Similarly, if the domestic water leaks
through a wall, it is collected within the air gap and is vented to atmosphere for leak detection.
The advantages of double-wall construction include:
 Prevention of cross-contamination
 Easy inspections and low maintenance
 Fully visible and vented leak detection between plates
 Potable water and heating medium are completely separated.
Leakage can be caused by corrosion, erosion, and vibration, and can result in the domestic
water system being contaminated by a heating medium, such as hydronic water, glycol
solution, etc.
There is no practical way to have the heating medium sterile or free from harmful treatment
compounds or corrosion by-products. A low pressure/temperature heating medium circuit
does not ensure contamination protection of indirect, single-wall water heaters. Whether they
are shell and tube, shell and coil, plate and frame, or any other type, all consist of relatively thin
wall heat transfer surfaces separating the heating medium from the domestic water system.
Therefore, the potential for cross contamination is real and in some instances contamination has
occurred.
Several states and cities are now insisting on double-wall vented construction in all indirect
type domestic water heaters. Plumbing codes have also been re-written to include double-
wall protection. See Figure 3-2 for an illustration of how a single wall and double wall differ in
construction, and how both function in the event of a hole, allowing fluid to leak through a plate.