Specification

Watts P3
Multi-Orifice Flow Control
for Tankless Heaters
Adjusts to 3, 3
1
⁄2 or 4 gpm
Watts No. P3 Flow Control valve is designed to limit the flow of water
to equipment and is used for tankless heater installations. It features a
multi-orifice design which lets you select a flow of 3, 3
1
⁄2 or 4 gpm,
simply and quickly, by turning the cap to the desired setting. If a dif-
ferent setting is desired, simply move the adjusting cap to the desired
setting, locating this over the matching line on the body.
Capacity
Watts No. P3 Flow Control is designed to give the rated capacity in
gallons per minute as numbered on the adjustment cap at 50 psig
supply pressure. For other pressures, refer to the Flow Table for corre-
sponding adjustment setting. It is recommended that supply pressure
be determined with a gauge to assure accurate flow. For example, 80
psi supply pressure results in the following:
Adjustment Setting No. Flow gpm @ 80 psi
3 3.8
3
1
⁄2 4.4
4 5.1
Installation
Multi-Orifice cylinder
adjusts to
3, 3
1
⁄2 or 4 gpm.
WATTS No. P3 No. Andover, MA
2
1
⁄ 2 33
1
⁄ 2 4
gpm
@
50 psi
*Adjustment Cap Settings
Dimensions
ES-P3
Hot Water
Boiler
Hot to
Appliances
Tempered
Watts 1170
Tempering
Valve
Cold
Watts 3L
Pressure
Relief
Watts P3
Tankless Heater
Dimensions
Model Size A B C Weight
P3
1
⁄2"1
5
⁄8"
1
⁄2" 2" 6 ozs.
A
B
C
Vertical marker line just to left of 3 gpm marker line signi-
fies minimum adjustable volume (approx. 2
1
⁄2 gpm) when
supply pressures exceed 50 psi.
Flow Table (gpm)
Adjustment
Supply Setting No.
Pressure psi 3 3
1
⁄2 4
30 2.3 2.7 3.1
40 2.7 3.1 3.6
*50 3 3.5 4
60 3.3 3.8 4.4
70 3.5 4.1 4.7
80 3.8 4.4 5.1
90 4 4.7 5.3
100 4.2 4.9 5.6
110 4.5 5.2 5.9
120 4.6 5.4 6.2
130 4.8 5.6 6.4
140 5 5.8 6.7
150 5.2 6.1 6.9
▼
Hot
Watts No. 174A
Job Name Contractor
Job Location Approval
Engineer Contractor’s P.O. No.
Approval Representative
USA: 815 Chestnut St., No. Andover, MA 01845-6098; www.wattsreg.com
Canada: 5435 North Service Rd., Burlington, ONT. L7L 5H7; www.wattscda.com