LX Circulation Pump with Air Switch Option TDA100 1HPThe TDA75 will fit most Hot Tubs, and is a replacement for Rocoi LDPB 140B. This pump can also be installed for Whirlpool Baths that use an air switch facility. By purchasing the TBS106A air switch you can therefore install this, interrupting the incoming live wire through the air switch. This pump is the same as the DXD pump and EA350 pump also found on the market, check watts or amp draw to be certain or call us. Information Plumbing Connection 1.