Trian Fund Management SC 13D/A PENTAIR plc

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 13D

Under the Securities Exchange Act of 1934

(Amendment No.1)*

PENTAIR PLC

(Name of Issuer)

Ordinary Shares, nominal value $0.01 per share

(Title of Class of Securities)

G7S00T 104

(CUSIP Number)

Brian L. Schorr, Esq.

Trian Fund Management, L.P.

280 Park Avenue, 41st Floor

New York, New York 10017

Tel. No.: (212) 451-3000

(Name, Address and Telephone Number of Person

Authorized to Receive Notices and Communications)

July 10, 2015

(Date of Event Which Requires Filing of this Statement)

If the filing person has previously filed a statement on Schedule 13G to report the acquisition which is the subject of this Schedule 13D, and is filing this schedule because of §§ 240.13d-1(e), 240.13d-1(f) or 240.13d-1(g), check the following box [ ].

Note: Schedules filed in paper format shall include a signed original and five copies of the schedule, including all exhibits. See Rule 13d-7 for other parties to whom copies are to be sent.

*The remainder of this cover page shall be filled out for a reporting person’s initial filing on this form with respect to the subject class of securities, and for any subsequent amendment containing information which would alter disclosures provided in a prior cover page.

The Information required on the remainder of this cover page shall not be deemed to be “filed” for the purpose of Section 18 of the Securities Exchange Act of 1934 (“Act”) or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).

1	NAME OF REPORTING PERSON S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON Nelson Peltz
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP			(a) [_] (b) [_]
3	SEC USE ONLY
4	SOURCE OF FUNDS AF
5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) or 2(e)			[_]
6	CITIZENSHIP OR PLACE OF ORGANIZATION United States
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH		7	SOLE VOTING POWER 0
		8	SHARED VOTING POWER 13,005,377
		9	SOLE DISPOSITIVE POWER 0
		10	SHARED DISPOSITIVE POWER 13,005,377
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 13,005,377
12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES			[ ]
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 7.24%*
14	TYPE OF REPORTING PERSON IN

_______

*Calculated based on 179,638,771 ordinary shares outstanding as of March 28, 2015, as reported in the Issuer’s Quarterly Report on Form 10-Q for the quarter ended March 28, 2015 (the “Form 10-Q”).

1	NAME OF REPORTING PERSON S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON Peter W. May
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP			(a) [_] (b) [_]
3	SEC USE ONLY
4	SOURCE OF FUNDS AF
5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) or 2(e)			[_]
6	CITIZENSHIP OR PLACE OF ORGANIZATION United States
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH		7	SOLE VOTING POWER 0
		8	SHARED VOTING POWER 13,005,377
		9	SOLE DISPOSITIVE POWER 0
		10	SHARED DISPOSITIVE POWER 13,005,377
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 13,005,377
12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES			[ ]
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 7.24%*
14	TYPE OF REPORTING PERSON IN

_______

* Calculated based on 179,638,771 ordinary shares outstanding as of March 28, 2015, as reported in the Issuer’s Form 10-Q.

1	NAME OF REPORTING PERSON S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON Edward P. Garden
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP			(a) [_] (b) [_]
3	SEC USE ONLY
4	SOURCE OF FUNDS AF
5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) or 2(e)			[_]
6	CITIZENSHIP OR PLACE OF ORGANIZATION United States
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH		7	SOLE VOTING POWER 0
		8	SHARED VOTING POWER 13,005,377
		9	SOLE DISPOSITIVE POWER 0
		10	SHARED DISPOSITIVE POWER 13,005,377
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 13,005,377
12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES			[ ]
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 7.24%*
14	TYPE OF REPORTING PERSON IN

_______

* Calculated based on 179,638,771 ordinary shares outstanding as of March 28, 2015, as reported in the Issuer’s Form 10-Q.

1	NAME OF REPORTING PERSON Trian Fund Management, L.P. S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON 20-3454182
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP			(a) [_] (b) [_]
3	SEC USE ONLY
4	SOURCE OF FUNDS AF
5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) or 2(e)			[_]
6	CITIZENSHIP OR PLACE OF ORGANIZATION Delaware
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH		7	SOLE VOTING POWER 0
		8	SHARED VOTING POWER 13,005,377
		9	SOLE DISPOSITIVE POWER 0
		10	SHARED DISPOSITIVE POWER 13,005,377
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 13,005,377
12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES			[ ]
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 7.24%*
14	TYPE OF REPORTING PERSON PN

_______

* Calculated based on 179,638,771 ordinary shares outstanding as of March 28, 2015, as reported in the Issuer’s Form 10-Q.

1	NAME OF REPORTING PERSON Trian Fund Management GP, LLC S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON 20-3454087
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP			(a) [_] (b) [_]
3	SEC USE ONLY
4	SOURCE OF FUNDS AF
5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) or 2(e)			[_]
6	CITIZENSHIP OR PLACE OF ORGANIZATION Delaware
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH		7	SOLE VOTING POWER 0
		8	SHARED VOTING POWER 13,005,377
		9	SOLE DISPOSITIVE POWER 0
		10	SHARED DISPOSITIVE POWER 13,005,377
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 13,005,377
12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES			[ ]
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 7.24%*
14	TYPE OF REPORTING PERSON OO

_______

* Calculated based on 179,638,771 ordinary shares outstanding as of March 28, 2015, as reported in the Issuer’s Form 10-Q.

1	NAME OF REPORTING PERSON Trian Partners Master Fund (ERISA), L.P. S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON 98-0682467
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP			(a) [_] (b) [_]
3	SEC USE ONLY
4	SOURCE OF FUNDS WC
5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) or 2(e)			[_]
6	CITIZENSHIP OR PLACE OF ORGANIZATION Cayman Islands
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH		7	SOLE VOTING POWER 0
		8	SHARED VOTING POWER 182,740
		9	SOLE DISPOSITIVE POWER 0
		10	SHARED DISPOSITIVE POWER 182,740
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 182,740
12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES			[X]
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 0.10%*
14	TYPE OF REPORTING PERSON PN

_______

* Calculated based on 179,638,771 ordinary shares outstanding as of March 28, 2015, as reported in the Issuer’s Form 10-Q.

1	NAME OF REPORTING PERSON Trian Partners, L.P. S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON 20-3453988
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP			(a) [_] (b) [_]
3	SEC USE ONLY
4	SOURCE OF FUNDS WC
5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) or 2(e)			[_]
6	CITIZENSHIP OR PLACE OF ORGANIZATION Delaware
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH		7	SOLE VOTING POWER 0
		8	SHARED VOTING POWER 2,670,342
		9	SOLE DISPOSITIVE POWER 0
		10	SHARED DISPOSITIVE POWER 2,670,342
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 2,670,342
12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES			[X]
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 1.49%*
14	TYPE OF REPORTING PERSON PN

_______

* Calculated based on 179,638,771 ordinary shares outstanding as of March 28, 2015, as reported in the Issuer’s Form 10-Q.

1	NAME OF REPORTING PERSON Trian Partners Master Fund, L.P. S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON 98-0468601
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP			(a) [_] (b) [_]
3	SEC USE ONLY
4	SOURCE OF FUNDS WC
5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) or 2(e)			[_]
6	CITIZENSHIP OR PLACE OF ORGANIZATION Cayman Islands
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH		7	SOLE VOTING POWER 0
		8	SHARED VOTING POWER 5,959,332
		9	SOLE DISPOSITIVE POWER 0
		10	SHARED DISPOSITIVE POWER 5,959,332
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 5,959,332
12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES			[X]
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 3.32%*
14	TYPE OF REPORTING PERSON PN

_______

* Calculated based on 179,638,771 ordinary shares outstanding as of March 28, 2015, as reported in the Issuer’s Form 10-Q.

1	NAME OF REPORTING PERSON Trian Partners Parallel Fund I, L.P. S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON 20-3694154
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP			(a) [_] (b) [_]
3	SEC USE ONLY
4	SOURCE OF FUNDS WC
5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) or 2(e)			[_]
6	CITIZENSHIP OR PLACE OF ORGANIZATION Delaware
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH		7	SOLE VOTING POWER 0
		8	SHARED VOTING POWER 261,894
		9	SOLE DISPOSITIVE POWER 0
		10	SHARED DISPOSITIVE POWER 261,894
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 261,894
12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES			[X]
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 0.15%*
14	TYPE OF REPORTING PERSON PN

_______

* Calculated based on 179,638,771 ordinary shares outstanding as of March 28, 2015, as reported in the Issuer’s Form 10-Q.

1	NAME OF REPORTING PERSON Trian Partners Strategic Investment Fund-A, L.P. S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON 27-4180625
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP			(a) [_] (b) [_]
3	SEC USE ONLY
4	SOURCE OF FUNDS WC
5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) or 2(e)			[_]
6	CITIZENSHIP OR PLACE OF ORGANIZATION Delaware
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH		7	SOLE VOTING POWER 0
		8	SHARED VOTING POWER 1,589,435
		9	SOLE DISPOSITIVE POWER 0
		10	SHARED DISPOSITIVE POWER 1,589,435
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 1,589,435
12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES			[X]
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 0.88%*
14	TYPE OF REPORTING PERSON PN

_______

* Calculated based on 179,638,771 ordinary shares outstanding as of March 28, 2015, as reported in the Issuer’s Form 10-Q.

1	NAME OF REPORTING PERSON Trian Partners Strategic Investment Fund-N, L.P. S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON 80-0958490
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP			(a) [_] (b) [_]
3	SEC USE ONLY
4	SOURCE OF FUNDS WC
5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) or 2(e)			[_]
6	CITIZENSHIP OR PLACE OF ORGANIZATION Delaware
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH		7	SOLE VOTING POWER 0
		8	SHARED VOTING POWER 407,995
		9	SOLE DISPOSITIVE POWER 0
		10	SHARED DISPOSITIVE POWER 407,995
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 407,995
12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES			[X]
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 0.23%*
14	TYPE OF REPORTING PERSON PN

_______

* Calculated based on 179,638,771 ordinary shares outstanding as of March 28, 2015, as reported in the Issuer’s Form 10-Q.

1	NAME OF REPORTING PERSON Trian Partners Strategic Investment Fund II, L.P. S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON 45-4929803
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP			(a) [_] (b) [_]
3	SEC USE ONLY
4	SOURCE OF FUNDS WC
5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) or 2(e)			[_]
6	CITIZENSHIP OR PLACE OF ORGANIZATION Delaware
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH		7	SOLE VOTING POWER 0
		8	SHARED VOTING POWER 902,609
		9	SOLE DISPOSITIVE POWER 0
		10	SHARED DISPOSITIVE POWER 902,609
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 902,609
12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES			[X]
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 0.50%*
14	TYPE OF REPORTING PERSON PN

_______

* Calculated based on 179,638,771 ordinary shares outstanding as of March 28, 2015, as reported in the Issuer’s Form 10-Q.

1	NAME OF REPORTING PERSON Trian Partners Strategic Investment Fund-D, L.P. S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON 98-1108184
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP			(a) [_] (b) [_]
3	SEC USE ONLY
4	SOURCE OF FUNDS WC
5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) or 2(e)			[_]
6	CITIZENSHIP OR PLACE OF ORGANIZATION Cayman Islands
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH		7	SOLE VOTING POWER 0
		8	SHARED VOTING POWER 364,145
		9	SOLE DISPOSITIVE POWER 0
		10	SHARED DISPOSITIVE POWER 364,145
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 364,145
12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES			[X]
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 0.20%*
14	TYPE OF REPORTING PERSON PN

_______

* Calculated based on 179,638,771 ordinary shares outstanding as of March 28, 2015, as reported in the Issuer’s Form 10-Q.

1	NAME OF REPORTING PERSON Trian Partners Fund (Sub)-G, L.P. S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON 90-1035117
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP			(a) [_] (b) [_]
3	SEC USE ONLY
4	SOURCE OF FUNDS WC
5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) or 2(e)			[_]
6	CITIZENSHIP OR PLACE OF ORGANIZATION Delaware
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH		7	SOLE VOTING POWER 0
		8	SHARED VOTING POWER 106,099
		9	SOLE DISPOSITIVE POWER 0
		10	SHARED DISPOSITIVE POWER 106,099
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 106,099
12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES			[X]
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 0.06%*
14	TYPE OF REPORTING PERSON PN

_____________

* Calculated based on 179,638,771 ordinary shares outstanding as of March 28, 2015, as reported in the Issuer’s Form 10-Q.

1	NAME OF REPORTING PERSON Trian Partners Strategic Fund-G II, L.P. S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON 46-5509975
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP			(a) [_] (b) [_]
3	SEC USE ONLY
4	SOURCE OF FUNDS WC
5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) or 2(e)			[_]
6	CITIZENSHIP OR PLACE OF ORGANIZATION Delaware
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH		7	SOLE VOTING POWER 0
		8	SHARED VOTING POWER 361,725
		9	SOLE DISPOSITIVE POWER 0
		10	SHARED DISPOSITIVE POWER 361,725
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 361,725
12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES			[X]
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 0.20%*
14	TYPE OF REPORTING PERSON PN

_______

* Calculated based on 179,638,771 ordinary shares outstanding as of March 28, 2015, as reported in the Issuer’s Form 10-Q.

1	NAME OF REPORTING PERSON Trian Partners Strategic Fund-G III, L.P. S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON 47-2121971
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP			(a) [_] (b) [_]
3	SEC USE ONLY
4	SOURCE OF FUNDS WC
5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) or 2(e)			[_]
6	CITIZENSHIP OR PLACE OF ORGANIZATION Delaware
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH		7	SOLE VOTING POWER 0
		8	SHARED VOTING POWER 199,061
		9	SOLE DISPOSITIVE POWER 0
		10	SHARED DISPOSITIVE POWER 199,061
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 199,061
12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES			[X]
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 0.11%*
14	TYPE OF REPORTING PERSON PN

_______

* Calculated based on 179,638,771 ordinary shares outstanding as of March 28, 2015, as reported in the Issuer’s Form 10-Q.

This Amendment No. 1 amends and supplements the Schedule 13D filed with the Securities and Exchange Commission on June 30, 2015 (the “Original Schedule 13D”) relating to the Ordinary Shares, nominal value $0.01 per share (the “Shares”), of Pentair plc, an Irish public limited company (the “Issuer”). The address of the principal executive office of the Issuer is P.O. Box 471, Sharp Street, Walkden, Manchester, M28 8BU United Kingdom.

Capitalized terms not defined herein shall have the meaning ascribed to them in the Original Schedule 13D. Except as set forth herein, the Original Schedule 13D is unmodified.

Items 3, 4, 5 and 6 of the Original Schedule 13D are hereby amended and supplemented as follows:

Item 3. Source and Amount of Funds or Other Consideration

Item 3 of the Original Schedule 13D is hereby amended and supplemented by adding the following information:

On July 10, 2015, Trian Onshore and Trian Offshore exercised all of their respective Options to purchase 6,216,586 Shares for an aggregate exercise price of $389,339,849 (See Schedule A to the Original Schedule 13D for additional detail regarding the Options). The source of funding for such transactions was the general working capital of Trian Onshore and Trian Offshore respectively.

Item 4. Purpose of Transaction

Item 4 of the Original Schedule 13D is hereby amended and supplemented by adding the following information:

The purpose of the transactions effected on July 10, 2015 was to exercise all of the Options and acquire Shares of the Issuer.

Item 5. Interest in Securities of the Issuer

Item 5 of the Original Schedule 13D is hereby amended and supplemented by adding the following information:

(a) As of July 13, 2015, the Reporting Persons beneficially owned, in the aggregate, 13,005,377 Shares, representing approximately 7.24% of the Issuer’s outstanding Shares (calculated based on 179,638,771 ordinary shares outstanding as of March 28, 2015, as reported in the Issuer’s Quarterly Report on Form 10-Q for the quarter ended March 28, 2015 (the “Form 10-Q”)). The total Shares include 6,788,791 Shares previously purchased by the Trian Entities and 1,466,600 Shares purchased by Trian Onshore and 4,749,986 Shares purchased by Trian Offshore, upon the July 10, 2015 exercise of all of the Options in accordance with their terms as described in Schedule A to the Original Schedule 13D.

(c) The transactions described in Item 3 herein, which are incorporated by reference into this Item 5(c) as if restated in full, describe all of the transactions in the Shares and Options that were effected since the filing of the Original Schedule 13D by the Reporting Persons, inclusive of all transactions effected through 4:00 p.m., New York City time, on July 13, 2015. The transactions described in Item 3 were affected in privately negotiated transactions with each Counterparty.

Item 6. Contracts, Arrangements, Understandings or Relationship with Respect to Securities of the Issuer

Item 6 of the Original Schedule 13D is hereby amended and supplemented by adding the following information:

The disclosures in Items 3 and 5 are incorporated herein by reference.

[INTENTIONALLY LEFT BLANK]

SIGNATURE

After reasonable inquiry and to the best of each of the undersigned knowledge and belief, each of the undersigned certifies that the information set forth in this statement is true, complete and correct.

Dated: July 13, 2015

TRIAN FUND MANAGEMENT, L.P.
By:	Trian Fund Management GP, LLC, its general partner

By:	/s/ EDWARD P. GARDEN
	Name:	Edward P. Garden
	Title:	Member

TRIAN FUND MANAGEMENT GP, LLC

By:	/s/ EDWARD P. GARDEN
	Name:	Edward P. Garden
	Title:	Member

TRIAN PARTNERS, L.P.
By:	Trian Partners GP, L.P., its general partner

By:	Trian Partners General Partner, LLC, its general partner

By:	/s/ EDWARD P. GARDEN
	Name:	Edward P. Garden
	Title:	Member

TRIAN PARTNERS MASTER FUND (ERISA) L.P.
By:	Trian Partners (ERISA) GP, L.P., its general partner

By:	Trian Partners (ERISA) General Partner, LLC, its general partner

By:	/s/ EDWARD P. GARDEN
	Name:	Edward P. Garden
	Title:	Member

TRIAN PARTNERS MASTER FUND, L.P.
By:	Trian Partners GP, L.P., its general partner

By:	Trian Partners General Partner, LLC, its general partner

By:	/s/ EDWARD P. GARDEN
	Name:	Edward P. Garden
	Title:	Member

TRIAN PARTNERS PARALLEL FUND I, L.P.
By:	Trian Partners Parallel Fund I General Partner, LLC, its general partner

By:	/s/ EDWARD P. GARDEN
	Name:	Edward P. Garden
	Title:	Member

TRIAN PARTNERS STRATEGIC INVESTMENT FUND-A, L.P.
By:	Trian Partners Strategic Investment Fund-A GP, L.P., its general partner

By:	Trian Partners Strategic Investment Fund-A General Partner, LLC, its general partner

By:	/s/ EDWARD P. GARDEN
	Name:	Edward P. Garden
	Title:	Member

TRIAN PARTNERS STRATEGIC INVESTMENT FUND-N, L.P.
By:	Trian Partners Strategic Investment Fund-N GP, L.P., its general partner

By:	Trian Partners Strategic Investment Fund-N General Partner, LLC., its general partner

By:	/s/ EDWARD P. GARDEN
	Name:	Edward P. Garden
	Title:	Member

TRIAN PARTNERS STRATEGIC INVESTMENT FUND II, L.P.
By:	Trian Partners Strategic Investment Fund II GP, L.P., its general partner

By:	Trian Partners Strategic Investment Fund-II General Partner, LLC., its general partner

By:	/s/ EDWARD P. GARDEN
	Name:	Edward P. Garden
	Title:	Member

TRIAN PARTNERS STRATEGIC INVESTMENT FUND-D, L.P.
By:	Trian Partners Strategic Investment Fund-D GP, L.P., its general partner

By:	Trian Partners Strategic Investment Fund-D General Partner, LLC, its general partner

By:	/s/ EDWARD P. GARDEN
	Name:	Edward P. Garden
	Title:	Member

TRIAN PARTNERS FUND (SUB)-G, L.P.
By:	Trian Partners Investment Fund-G GP, L.P., its general partner

By:	Trian Partners Investment Fund-G General Partner, LLC, its general partner

By:	/s/ EDWARD P. GARDEN
	Name:	Edward P. Garden
	Title:	Member


TRIAN PARTNERS STRATEGIC FUND-G II, L.P.
By:	Trian Partners Strategic Fund-G II GP, L.P., its general partner

By:	Trian Partners Strategic Fund-G II General Partner, LLC, its general partner

By:	/s/ EDWARD P. GARDEN
	Name:	Edward P. Garden
	Title:	Member

TRIAN PARTNERS STRATEGIC FUND-G III, L.P.
By:	Trian Partners Strategic Fund-G III GP, L.P., its general partner

By:	Trian Partners Strategic Fund-G III General Partner, LLC, its general partner

By:	/s/ EDWARD P. GARDEN
	Name	Edward P. Garden
	Title	Member

/s/NELSON PELTZ Nelson Peltz
/s/PETER W. MAY Peter W. May
/s/EDWARD P. GARDEN Edward P. Garden

Exhibit 1

JOINT FILING AGREEMENT

In accordance with Rule 13d-1(k)(1) under the Securities Exchange Act of 1934, as amended, the persons named below agree to the joint filing on behalf of each of them of a statement on Schedule 13D (including amendments thereto) with respect to the Ordinary Shares of Pentair plc. and further agree that this Joint Filing Agreement be included as an Exhibit to such joint filings. In evidence thereof, the undersigned, being duly authorized, have executed this Joint Filing Agreement this 13th day of July 2015.

TRIAN FUND MANAGEMENT, L.P.
By:	Trian Fund Management GP, LLC, its general partner

By:	/s/ EDWARD P. GARDEN
	Name:	Edward P. Garden
	Title:	Member

TRIAN FUND MANAGEMENT GP, LLC

By:	/s/ EDWARD P. GARDEN
	Name:	Edward P. Garden
	Title:	Member

TRIAN PARTNERS, L.P.
By:	Trian Partners GP, L.P., its general partner

By:	Trian Partners General Partner, LLC, its general partner

By:	/s/ EDWARD P. GARDEN
	Name:	Edward P. Garden
	Title:	Member

TRIAN PARTNERS MASTER FUND (ERISA) L.P.
By:	Trian Partners (ERISA) GP, L.P., its general partner

By:	Trian Partners (ERISA) General Partner, LLC, its general partner

By:	/s/ EDWARD P. GARDEN
	Name:	Edward P. Garden
	Title:	Member

TRIAN PARTNERS MASTER FUND, L.P.
By:	Trian Partners GP, L.P., its general partner

By:	Trian Partners General Partner, LLC, its general partner

By:	/s/ EDWARD P. GARDEN
	Name:	Edward P. Garden
	Title:	Member

TRIAN PARTNERS PARALLEL FUND I, L.P.
By:	Trian Partners Parallel Fund I General Partner, LLC, its general partner

By:	/s/ EDWARD P. GARDEN
	Name:	Edward P. Garden
	Title:	Member

TRIAN PARTNERS STRATEGIC INVESTMENT FUND-A, L.P.
By:	Trian Partners Strategic Investment Fund-A GP, L.P., its general partner

By:	Trian Partners Strategic Investment Fund-A General Partner, LLC, its general partner

By:	/s/ EDWARD P. GARDEN
	Name:	Edward P. Garden
	Title:	Member

TRIAN PARTNERS STRATEGIC INVESTMENT FUND-N, L.P.
By:	Trian Partners Strategic Investment Fund-N GP, L.P., its general partner

By:	Trian Partners Strategic Investment Fund-N General Partner, LLC., its general partner

By:	/s/ EDWARD P. GARDEN
	Name:	Edward P. Garden
	Title:	Member

TRIAN PARTNERS STRATEGIC INVESTMENT FUND II, L.P.
By:	Trian Partners Strategic Investment Fund II GP, L.P., its general partner

By:	Trian Partners Strategic Investment Fund-II General Partner, LLC., its general partner

By:	/s/ EDWARD P. GARDEN
	Name:	Edward P. Garden
	Title:	Member

TRIAN PARTNERS STRATEGIC INVESTMENT FUND-D, L.P.
By:	Trian Partners Strategic Investment Fund-D GP, L.P., its general partner

By:	Trian Partners Strategic Investment Fund-D General Partner, LLC, its general partner

By:	/s/ EDWARD P. GARDEN
	Name:	Edward P. Garden
	Title:	Member

TRIAN PARTNERS FUND (SUB)-G, L.P.
By:	Trian Partners Investment Fund-G GP, L.P., its general partner

By:	Trian Partners Investment Fund-G General Partner, LLC, its general partner

By:	/s/ EDWARD P. GARDEN
	Name:	Edward P. Garden
	Title:	Member


TRIAN PARTNERS STRATEGIC FUND-G II, L.P.
By:	Trian Partners Strategic Fund-G II GP, L.P., its general partner

By:	Trian Partners Strategic Fund-G II General Partner, LLC, its general partner

By:	/s/ EDWARD P. GARDEN
	Name:	Edward P. Garden
	Title:	Member

TRIAN PARTNERS STRATEGIC FUND-G III, L.P.
By:	Trian Partners Strategic Fund-G III GP, L.P., its general partner

By:	Trian Partners Strategic Fund-G III General Partner, LLC, its general partner

By:	/s/ EDWARD P. GARDEN
	Name	Edward P. Garden
	Title	Member

/s/NELSON PELTZ Nelson Peltz
/s/PETER W. MAY Peter W. May
/s/EDWARD P. GARDEN Edward P. Garden

Trian Fund Management SC 13D/APENTAIR plc