Crown 29PT9467S manual Series 24 Minimum Piping Recommendations Steam Boiler, ‘A’

Recommendation 3 is used when the return water temperature goes below 135°F for prolonged periods of time. This is also primary-secondary piping, but includes the addition of a 3-way valve, return water sensor and boiler-mounted RTC Return Temperature Control.

SYSTEM			SYSTEM	MAX
	MAX		PUMP
PUMP					CLOSELY
		CLOSELY		4D
	4D				SPACED
		SPACED	1 SUPPLY
1 SUPPLY					TEES
		TEES
3 DIVERTING		D	3 DIVERTING		D
VALVE & ACTUATOR			VALVE & ACTUATOR
1 SUPPLY		SEE NOTE 5	1 SUPPLY
					SEE NOTE 5
BOILER CIRCULATOR		2 RETURN	BOILER CIRCULATOR
			(BY OTHERS - SEE NOTE 5)
(BY OTHERS - SEE NOTE 5)					2 RETURN
		SEE NOTE 6
			DRAIN VALVE
DRAIN VALVE					SEE NOTE 6
			(SEE NOTE 4)
(SEE NOTE 4)
		3” x 12” NIPPLE
		AND BELL REDUCER
		(SEE NOTE 4)

PIPE SIZING AND NOTES FOR RECOMMENDATION 3

REAR OF	2	REAR OF	2
BOILER	RETURN	BOILER	RETURN
24-03 THRU 24-11 (W/20°F DROP)	RETURN	2B	RETURN HEADER
24-03 THRU 24-12 (W/40°F DROP)	SENSOR (SEE NOTE 7)	RETURN BRANCH	RETURN 2A
			SENSOR
		24-12 (W/20°F DROP)	(SEE NOTE 7)

				RETURN PIPING SIZE (IN)
	SUPPLY				RETURN	RETURN	Notes:
	PIPING				HEADER	BRANCH
	SIZE (IN) (1)		RETURN (2)		(2A)	(QTY.) SIZE (2B)	1. All piping is schedule 40.
BOILER	20°F	40°F	20°F	40°F	20°F	20°F	2.	Pipe sizes listed are based on a 20° F or 40°F differential (temperature drop).
MODEL	DROP	DROP	DROP	DROP	DROP	DROP		Select one to match application.
24-03	2	1-1/2	2	1-1/2	–	–	3.	When specified return piping is less than 3”, install 3” x 12” nipple and appropriate
24-04	2	1-1/2	2	1-1/2	–	–		size bell reducer directly into boiler return tapping as shown.
							4.	Drain valve—ball valve preferable, gate valve acceptable alternative
24-05	2	1-1/2	2	1-1/2	–	–
								(supplied by others).—Minimum valve size per ASME code is 3/4” NPT.
24-06	2-1/2	1-1/2	2-1/2	1-1/2	–	–
							5.	Maximum linear feet of pipe from 3-way bypass port to sensor location = 11 feet.
24-07	2-1/2	2	2-1/2	2	–	–
								Bypass line shall be the same diameter as return A.
24-08	2-1/2	2	2-1/2	2	–	–
							6.	Minimum linear feet of pipe from point of mixing (where bypass meets return line)
24-09	3	2	3	2	–	–
								to sensor location = 4 feet.
24-10	3	2-1/2	3	2-1/2	–	–
							7.	Install special 3” x 12” nipple with 1/4” NPT side tapping closest to boiler.
24-11	3	2-1/2	3	2-1/2	–	–
								Where applicable, use bell reducer to adapt to recommended return pipe size.
24-12	4	2-1/2	4	2-1/2	3	(2) 3	8.	Proper boiler circulator sizing is listed in RTC literature.

Series 24 Minimum Piping Recommendations – Steam Boiler

1		‘A’
	(SEE NOTE 5)	1
	2
2
(SEE NOTE 4)		2

(SEE NOTE 4)

4

4

(SEE NOTE 3)

3
	24-03 THRU 24-06				3
		PIPING SIZE (IN)				RISER
					SPACING (IN)
	RISER	HEADER
BOILER	(QTY.)	& SUPPLY	RETURN	EQUALIZER
MODEL	SIZE (1)	(2)	(3)	(4)	‘A’	‘B’
24-03	(1) 3”	3”	1-1/2”	2”	–	–
24-04	(1) 4”	4”	2”	2”	–	–
24-05	(1) 4”	4”	2”	2”	–	–
24-06	(1) 4”	4”	2-1/2”	2-1/2”	–	–
24-07	(2) 4”	6”	2-1/2”	2-1/2”	36”	–
24-08	(2) 4”	6”	2-1/2”	2-1/2”	42”	–
24-09	(2) 4”	6”	2-1/2”	2-1/2”	48”	–
24-10	(2) 4”	6”	3”	3”	54”	–
24-11	(2) 4”	6”	3”	3”	60”	–
24-12	(3) 4”	6”	3”	3”	30”	36”

		‘A’
(SEE NOTE 5)	18” MIN.			1
			‘B’
2				RISER
	24” MIN.			(SEE NOTE 5)
					2
	2			SUPPLY
					WATER LINE
	HEADER	SEE NOTE 2
(SEE NOTE 3)					BLOW-OFF/
	(SEE NOTE 4)			2” TO 4”
					DRAIN VALVE
4	EQUALIZER
					(SEE NOTE 3)
24-07 THRU 24-11	CLOSE NIPPLE
	HARTFORD LOOP			REAR OF BOILER
(REQ’D ON GRAVITY
RETURN SYSTEM) 3

RETURN

DRAIN VALVE (WET RETURN)

24-12

Notes:

1.All piping is schedule 40.

2.To prevent condensate from being trapped in header, do not reduce equalizer elbow at header connection.

3.Drain/blowoff valve—ball valve preferable, gate valve acceptable alternative (supplied by others).

•Mininim valve size per ASME code is 3/4” NPT 24-03/24-05; 1” NPT 24-06/24-10; 1-1/4” NPT 24-11/24-12.

•Increasing the valve size will improve the blowdown operation

•In all cases, piping connection blowoff valve to boiler should be full size to the point of discharge.

4.For pumped return systems, see Series 24 installation manual.