TK-510U Gas Conversion Guide
Adjusting the manifold pressure can cause unexpected combustion conditions during operation,
which can cause a health hazard, damage the water heater, and/or shorten its lifespan.
Therefore, the manifold pressure must only be changed by a qualified service agency or a gas
utility service technician in accordance with Manufacturer’s written instructions and all applicable
codes and requirements of the authority having jurisdiction.
WARNING
Checking maximum and minimum manifold pressure
i. Ensure that the water heater is not in operation.
ii. Remove the screw off the manifold port of the water heater. (Fig.A)
iii. Connect a manometer to the manifold port using a silicon tube (Fig. B). Ensure that this connection is secure enough to
prevent a gas leak.
iv. Turn on power supply to the water heater.
v. Turn on both gas and water valves to the water heater.
vi. Turn on hot water fixtures to produce a high flow. If an isolation valve is installed, hook up a water hose to the hot outlet
and run water at maximum rate.
vii. Verify the MAX and MIN settings as follows:
a. Press and hold the “MAX” button on the computer board. (See Figure C.)
b. Compare the reading on the manometer to the values in the table on the right. If it does not fall within the
acceptable range, refer to “Adjusting maximum manifold pressure.”
c. Press and hold the “MIN” button on the computer board. (See Figure C.)
d. Compare the reading on the manometer to the values in the table on the right. If it does not fall within the
acceptable range, refer to “Adjusting minimum manifold pressure.”
Adjusting maximum manifold pressure
• Press and hold down the “MAX” button on the computer board. While holding down the “MAX” button, press either the
“Increase” or “Decrease” button to increase or decrease the manifold gas pressure, respectively (Fig. C). Do not push
the increase or decrease button for more than two seconds at a time. Refer to the manometer to verify that pressure
has been set to the desired value.
Adjusting minimum manifold pressure
• Press and hold down the “MIN” button on the computer board. While holding down the “MIN” button, press either the
“Increase” or “Decrease” button to increase or decrease the manifold gas pressure, respectively (Fig. C). Do not push the
increase or decrease button for more than two seconds at a time. Refer to the manometer to verify that pressure has
been set to the desired value.
viii. After gas pressure has been set, turn off the power supply and turn off both gas and water valves. Next, remove the
manometer tube, and replace the port screw securely. If the screw isn’t fastened securely at this time, it may cause a gas leak.
Models for Propane
110U Indoor
AT-KJr3U-IN
310U Indoor
AT-K5U-IN
510U Indoor
AT-D3U-IN
Manifold Pressure
Inch
W.C.
(Pa)
Max.
1.47 to 1.77
(366 to 440)
Max.
2.42 to 3.00
(602 to 747)
Max.
2.65 to 3.27
(659 to 814)
Min.
0.41 to 0.52
(102 to 129)
Min.
0.41 to 0.52
(102 to 129)
Min.
0.41 to 0.52
(102 to 129)
Models for Propane
110U Outdoor
AT-KJr3U-OS
310U Outdoor
AT-K5U-OS
510U Outdoor
AT-D3U-OS
Manifold Pressure
Inch
W.C.
(Pa)
Max.
1.78 to 2.02
(443 to 503)
Max.
3.02 to 3.41
(751 to 849)
Max.
3.22 to 3.61
(801 to 898)
Min.
0.47 to 0.57
(117 to 142)
Min.
0.47 to 0.57
(117 to 142)
Min.
0.47 to 0.57
(117 to 142)
Computer
board
Manifold port
Fig. A
Fig. C
MAX. button
MIN. button
Increase button
Decrease button
110U / 310U computer board
MIN. button
MAX. button
Increase button
Decrease button
510U computer board
Fig. B
Computer
board
Silicone
Tube
To manometer
Unit: kBTU per hour
Pipe Size Length
Diameter
10'
(3.0m)
20'
(6.1m)
30'
(9.1m)
40'
(12.2m)
50'
(15.2m)
60'
(18.3m)
70'
(21.3m)
80'
(24.4m)
90'
(27.4m)
100'
(30.5m)
125'
(38.1m)
150'
(45.7m)
200'
(61.0m)
1/2"
268 184 148 126 112 101 93 87 82 77 68 62 53
3/4"
567 393 315 267 237 217 196 185 173 162 146 132 112
1"
1,071 732 590 504 448 409 378 346 322 307 275 252 213
1
1/4"
2,205 1,496 1,212 1,039 913 834 771 724 677 630 567 511 440
1
1/2"
3,307 2,299 1,858 1,559 1,417 1,275 1,181 1,086 1,023 976 866 787 675
2"
6,221 4,331 3,465 2,992 2,646 2,394 2,205 2,047 1,921 1,811 1,606 1,496 1,260
-Propane (LP) Supply Piping-
Maximum Capacity of Propane (LP) Based on 11" W.C. supply pressure at a 0.5" W.C. pressure drop
• The minimum and maximum inlet gas pressures for propane are:
Gas type Inlet gas pressure
Propane Min. 8.0” W.C. (1.99 kPa) – Max. 14.0” W.C. (3.48 kPa)
GAS SUPPLY AND GAS PIPE SIZING FOR PROPANE
• Size the gas pipe to supply the necessary volume of gas for the water heater.
Refer to and follow the requirements listed in the current edition of ANSI Z223.1/NFPA 54
(USA), B149.1 (Canada), or local codes. Otherwise, flow capabilities and output tempera-
tures will be limited.
• When the gas connections are completed, it is necessary to perform a gas leak test either
by applying soapy water to all gas fittings and observing for bubbles or by using a gas leak
detection device.
i. The water heater and its individual shutoff valve must be disconnected from the gas
supply piping system during any pressure testing of that system at test pressures in
excess of 1/2 psi (3.5 kPa).
ii. The water heater must be isolated from the gas supply piping system by closing its
individual manual shutoff valve during any pressure testing of the gas supply piping
system at test pressures equal to or less than 1/2 psi (3.5 kPa).
• Regarding high altitude installation after gas conversion, refer to the “HIGH ALTITUDE
INSTALLATIONS” section of the installation manual. (P. 12)
WARNING
Models for Propane
110U Indoor/Outdoor
AT-KJr3U-IN/OS
310U Indoor/Outdoor
AT-K5U-IN/OS
510U Indoor/Outdoor
AT-D3U-IN/OS
BTU Input
BTU/h
Max. 140,000 Max. 190,000 Max. 199,000
Min. 15,000 Min. 15,000 Min. 15,000
BTU Input
Manifold Pressure