<PAGE>   1
                                                                   Exhibit 10.45


                       FIRST AMENDMENT TO CREDIT AGREEMENT


    This First Amendment to Credit Agreement ("First Amendment") is made this
12th day of February, 1997, effective as of October 31, 1996, by all of the
current parties to that certain Credit Agreement dated as of October 31, 1996 by
and among Commercial Intertech Corp., Commercial Intertech Holdings Limited,
Mellon Bank, N.A., as Agent, and the Banks party thereto (the "Credit
Agreement").

    WHEREAS, pursuant to that certain Syndication Assignment and Assumption
Agreement dated as of January 7, 1997, among other things, certain Banks (as
defined in the Credit Agreement) became additional parties to the Credit
Agreement; and

    WHEREAS, all of the current parties to the Credit Agreement desire that
certain clarifications or corrections be made to the Credit Agreement in order
to reflect and more clearly give effect to their collective understanding of the
agreements among them concerning certain of the matters addressed in the Credit
Agreement and Exhibit 8.3.3 thereto.

    NOW THEREFORE, in consideration of the mutual covenants herein contained and
intending to be legally bound hereby, the parties hereto agree as follows:

    1.   AMENDMENT OF CREDIT AGREEMENT.  The Credit Agreement is hereby amended
         as follows:

                  (a) The definition of "Combined EBITDA" is hereby replaced in
its entirety by following revised definition:

                  COMBINED EBITDA for any period of determination shall mean an
         amount equal to the sum of (i) the net income (excluding income (or
         loss) of any Person in which any Combined TEC Group Entity has an
         equity interest of 50% or less, except to the extent of the amount of
         dividends or other distributions actually paid in cash by such Person
         to any Combined TEC Group Entity during such period) for such period,
         plus (ii) interest expense in respect of Indebtedness to the extent
         deducted in determining net income for such period ("Interest
         Expense"), plus (iii) the provision for domestic and foreign taxes for
         such period based on income or profits to the extent such income or
         profits were included in computing net income for such period, plus
         (iv) depreciation deducted in determining net income for such period,
         plus (v) amortization deducted in determining net income for such
         period, plus (vi) only with respect to TEC's 1996 and 1997 fiscal
         years, expense to the extent deducted in determining net income for
         such period in respect of fees and costs which were incurred in
         connection with the Tender Offer and the CUNO Spin-Off (provided, that
         no such expense described in this clause (vi) shall be added to
         determine Combined EBITDA for any period of determination if the
         aggregate expense for that period of determination together with all
         expense included in determining net income in all periods prior to the
         period of determination for all such fees and costs would exceed
         $8,000,000), in each case


<PAGE>   2



         of the Combined TEC Group for such period determined on a combined
         basis in accordance with GAAP; provided, however, that there shall be
         excluded from the foregoing computation (A) all non-cash extraordinary
         income, gains and losses (with extraordinary charges related to the
         write-off of capitalized fees and expenses associated with the Tender
         Offer and Cuno Spin-Off being deemed non-cash items) and (B) all gains
         or losses from the sale of assets not sold in the ordinary course of
         business, to the extent either or both were included in net income
         under the foregoing clause (i) for such period.

                  (b) The definition of Combined Interest Expense is hereby
replaced in its entirety by the following revised definition:

         COMBINED INTEREST EXPENSE for any period of determination shall be
         equal to the Interest Expense of the Combined TEC Group as defined and
         determined in clause (ii) of the definition of the term "Combined
         EBITDA" for such period on a combined basis in accordance with GAAP,
         less any amortization of fees and costs which were incurred and paid in
         connection with the Tender Offer and the CUNO Spin-Off to the extent
         the same are included in Interest Expense for such period.

                  (c) The definition of US Euro-Rate Option is hereby replaced
in its entirety by the following revised definition:

         U.S. EURO-RATE OPTION shall mean a rate per annum (computed on the
         basis of a year of 360 days and actual days elapsed) equal to the US
         Euro-Rate plus the Applicable Margin.

                  (d) The last sentence of Section 8.3.2 is hereby replaced in
its entirety by the following revised sentence:

         The certificate or report of accountants shall be free of
         qualifications (other than any consistency qualification that may
         result from a change in the method used to prepare the financial
         statements as to which such accountants concur), and shall be
         accompanied by a letter or report of such accountants confirming TEC's
         calculations with respect to the certificate to be delivered pursuant
         to Section 8.3.3 with respect to such financial statements.

                  (e) Exhibit 8.3.3 to the Credit Agreement (Form of Compliance
Certificate) is hereby replaced in its entirety by the revised form of Exhibit
8.3.3 attached hereto as "First Amendment Exhibit A".




<PAGE>   3



         2.       MISCELLANEOUS:

                  (a) The First Amendment supersedes all prior understandings
and agreements, whether written or oral, between the parties hereto relating to
the transactions provided for herein.

                  (b) This First Amendment may be executed by different
signatories hereto on any number of separate counterparts, including facsimiles,
each of which when so executed and delivered, shall be an original, and all such
counterparts shall together constitute one and the same instrument.

         IN WITNESS WHEREOF, the parties have executed and delivered this Second
Amendment as of the date first set forth above.

                           [INTENTIONALLY LEFT BLANK]



<PAGE>   4



                  [SIGNATURE PAGE 1 OF 4 TO THE FIRST AMENDMENT
                              TO CREDIT AGREEMENT]


                                MELLON BANK, N.A.
                                By:
                                   --------------------------------
                                Name:
                                      -----------------------------
                                Title:
                                       ----------------------------

                                ABN AMRO BANK N.V.
                                By:
                                   --------------------------------
                                Name:
                                      -----------------------------
                                Title:
                                       ----------------------------

                                Notice Address:

                                One PPG Place
                                Suite 2950
                                Pittsburgh, PA 15222-5400

                                Telephone No.: 412-566-0984
                                Telecopier No.: 412-566-2266
                                Attn:   Chris Helmeci

                                THE BANK OF TOKYO - MITSUBISHI, LIMITED
                                By:
                                   --------------------------------
                                Name:
                                      -----------------------------
                                Title:
                                       ----------------------------

                                Notice Address:
                                1251 Avenue of the Americas, 12th Floor
                                New York, NY 10020-1104

                                Telephone No.: 212-782-4395
                                Telecopier No.: 212-782-4981
                                Attn: Akira Kikuchi

                                Notice Address:
                                12-15 Finsbury Circus
                                London, EC2M 7BT
                                U.K.
                                Telephone No.: 0171-577-1201
                                Telecopier No.: 0171-867-9610
                                Attn: Mr. David A. DiMatteo




<PAGE>   5



                  [SIGNATURE PAGE 2 OF 4 TO THE FIRST AMENDMENT
                              TO CREDIT AGREEMENT]

                                NBD BANK

                                By:
                                   --------------------------------
                                Name:
                                      -----------------------------
                                Title:
                                       ----------------------------

                                Notice Address:
                                611 Woodward Avenue
                                Detroit, MI 48226

                                Telephone No.: 313-225-3300
                                Telecopier No.: 313-225-3269
                                Attn: Andrew W. Strait

                                BANK ONE, COLUMBUS, NA

                                By:
                                   --------------------------------
                                Name:
                                      -----------------------------
                                Title:
                                       ----------------------------

                                Notice Address:
                                707 Brooksedge, Building No. 6
                                Department 1087
                                Westerville, OH 43280

                                Telephone No.: 614-248-8744
                                Telecopier No.: 614-248-8800
                                Attn: Steve Wasmer

                                NATIONAL CITY BANK, NORTHEAST

                                By:
                                   --------------------------------
                                Name:
                                      -----------------------------
                                Title:
                                       ----------------------------

                                Notice Address:
                                Corporate Banking Department
                                20 Federal Plaza
                                Youngstown, Ohio 44503

                                Telephone No.: 330-742-4218
                                Telecopier No.: 330-742-4308
                                Attn: B.J. Lumpkin



<PAGE>   6




                  [SIGNATURE PAGE 3 OF 4 TO THE FIRST AMENDMENT
                              TO CREDIT AGREEMENT]


                                THE BANK OF NEW YORK

                                By:
                                   --------------------------------
                                Name:
                                      -----------------------------
                                Title:
                                       ----------------------------

                                Notice Address:
                                One Wall Street - 22nd Floor
                                New York, NY 10286

                                Telephone No.: 212-635-7919
                                Telecopier No.: 212-635-6434
                                Attn: Robert J. Joyce

                                THE SANWA BANK, LIMITED, CHICAGO BRANCH

                                By:
                                   --------------------------------
                                Name:
                                      -----------------------------
                                Title:
                                       ----------------------------

                                Notice Address:
                                10 South Wacker Drive
                                31st Floor
                                Chicago, IL 60606

                                Telephone No.: 312-993-4336
                                Telecopier No.: 312-346-6677
                                Attn: Mr. Patrick McGushin

                                Notice Address:
                                P.O. Box 36
                                City Place House
                                55 Basinghall Street
                                London, EC2V 5DL

                                Telephone No.: 0171-330-5180
                                Telecopier No.: 0171-330-5555
                                Attn: Nigel Johnstone







<PAGE>   7



                    [SIGNATURE PAGE 4 OF 4 TO FIRST AMENDMENT
                              TO CREDIT AGREEMENT]


                                MELLON BANK, N.A. as Agent

                                By:
                                   --------------------------------

                                Title:
                                       ----------------------------


                                COMMERCIAL INTERTECH CORP.

                                By:
                                   --------------------------------

                                Title:
                                       ----------------------------

                                COMMERCIAL INTERTECH HOLDINGS
                                LIMITED

                                By:
                                   --------------------------------

                                Title:
                                       ----------------------------