Takagi T-K3 Service Manual

T-K3 Service Manual
Ver. 1.05
53
CONFI DENTIAL
12-10. Pump control ON/OFF conditions: BTU requirements for Intermittent mode
A. Calculating the pump’s ON/OFF condition
【Condition needed to turn the pump ON】
( T
set
– T
in
) × GPM × 500 > 18,600
【Condition needed to turn the pump OFF】
4 minutes after activation, if the computer detects a BTU requirement of less than 18,600
BTU/h, th e computer w ill stop the pu mp in 90 seconds.
( T
set
– T
in
) × GPM × 500 < 18,600 or T
in
= T
set
Where: T
set
= Output set temperature and T
in
= Inlet temperature
B. Calculation example
Set temperature: T
set
= 122 ˚ F Flow rate = 2.5 GPM
【Condition needed to turn the pump ON】
( 122 – T
in
) × 2.5 × 500 > 18,600 T
in
< 107.1˚F
【Condition needed to turn the pump OFF】
( 122 – T
in
) × 2.5 × 500 < 18,600 T
in
> 107.1 ˚F
C. ON/OFF table (ON values are the same as OFF values)
Flow rate of pump (GPM)
Set temperature
(˚F)
1.0 1.5 2.0 2.5 3.0 3.5 4.0
113 75.8 88.2 94.4 98.1 100.6 102.4 103.7
122 84.8 97.2 103.4 107.1 109.6 111.4 112.7
131 93.8 106.2 112.4 116.1 118.6 120.4 121.7
140 102.8 115.2 121.4 125.1 127.6 129.4 130.7
158 120.8 133.2 139.4 143.1 145.6 147.4 148.7
167 129.8 142.2 148.4 152.1 154.6 156.4 157.7
185 147.8 160.2 166.4 170.1 172.6 174.4 175.7

Takagi T-K3 Specifications

General

Type	Tankless
Installation Type	Indoor
Maximum BTU Input	199, 000 BTU/h
Gas Connection Size	3/4"
Vent Size	3"
Hot Water Flow Rate (at 35°C rise)	6.6 GPM
Maximum Input	199, 000 BTU/h