Weil-McLain WTGO Series Manual page 19

Connect Tankless Heater Piping
Studies have indicated that
dangerous bacteria can form in
potable water distribution systems if certain
minimum water temperatures are not maintained.
Contact local health department for more information.
To pipe tankless heater:
1. Size piping no smaller than tankless heater
inlet and outlet.
2. Following controls (furnished by others) must
be installed:
a. Automatic mixing valve. See FIGURE 15.
(Read
b. Flow regulating valve. Size according to
intermittent draw of tankless heater. See
Table at right. Follow valve manufacturer's
instructions to install.
3. Additional anti-scald devices may be installed at
each hot water faucet, bath and shower outlet.
4. In hard water areas, soften cold domestic supply
water to heaters to prevent lime build-up.
These single wall heat exchangers comply
with National Standard Plumbing Code
provided that:
• Boiler water (including additives) is
practically non-toxic, having a toxicity
rating or class of 1, as listed in Clinical
Toxicology of Commercial Products.
• Boiler water pressure is limited to max.
30 psig by approved water relief valve.
at bottom of page 18.)
Tankless Heater Piping
FIGURE 15
CONTINUED
TANKLESS HEATER RATINGS TABLE
BOILER
MODEL HEATER
NUMBER NUMBER
WTGO-3 WT-14
WTGO-4 WT-14
WTGO-5 WT-14
WTGO-6 WT-14
WTGO-7 WT-20
WTGO-8 WT-20
WTGO-9 WT-20
* Gallons of water per minute heated from 40°F to 140°F with 200°F
boiler water temperature. Tested in accordance with I=W=H Testing and
Rating Standard for Indirect Tankless Water Heaters Tested with Boilers.
Hot
Automatic Mixing
Valve
INTERMITTENT INLET
DRAW RATINGS AND OUTLET
(GPM)* TAPPING SIZES
3.25
3.75
4.00
4.25
5.50
5.75
6.00
Limit Control with
Tankless Control
Flow Regulating
Valve
Cold Water
Mixed
12" min.
Cold
½"
½"
½"
½"
½"
½"
½"
Supply
19