Operating instructions
2. Install relief valve in rear section on 3/4-in. nipple and street ell. Do not connect directly to a drain, but leave an air gap. No shutoff of any
description shall be placed between safety relief valve and boiler, or on discharge pipes between such safety valves and the atmosphere.
Installation of safety relief valve shall conform to requirements of the ANSI/ASME Boiler and Pressure Vessel Code, Section IV. The
manufacturer is not responsible for any water damage. Connect a drain line of the same pipe size (3/4-in.) to carry any water away to a drain.
3. Connect the 1–1/4-in. NPT supply and return lines to boiler. Both supply and return lines should be piped to the front section or both to
the rear section. The boiler should NOT be piped return line to the front, supply line to the rear, or vice versa, as this will cause boiler water
to short circuit heat exchanger. The connections may require certain additional fittings and parts as shown on diagrams. (See Fig. 9, 10, and
11.)
If installing an entire new heating system, first install all radiation units (panels, radiators, or cabinets) and supply and return mains, then make
connections to boiler.
In connecting cold water supply to reducing valve, make sure that a clean water supply is available. When water supply is from a well or pump,
a sand stainer should be installed at pump.
When boiler is used in connection with refrigeration systems, it shall be installed so that chilled medium is piped in parallel with the heating boiler
with appropriate valves to prevent chilled medium from entering the heating boiler.
The minimum boiler supply water temperature setting on the aquastat is 140°F. If the boiler is used in a heating system where supply water
temperatures below 140°F are desired, a suitable method, such as, the use of bypass piping shown in the figure 10, a 3 way or 4 way mixing
valve, or some other means needs to be used to ensure return water temperatures to the boiler are no less than 120°F. When the boiler is operated
with return water temperatures less than 120°F, condensation may form in the boiler and venting. This condensation is corrosive and can eventually
cause severe damage to the boiler and venting system.
Antifreeze added to boilers must be non-toxic and must be of a type specifically intended for use in closed hydronic heating systems. Under no
circumstances should automotive antifreeze be used. Antifreeze used in any boiler may reduce capacity by 10 percent or more and increase fuel
consumption. Tankless coil performance will fall as concentration of antifreeze is increased. Refer to boiler and piping water volumes tables on
next page.
PROCEDURE 5—CHIMNEY AND CHIMNEY CONNECTION
Follow local codes. In the absence of local codes, follow ANSI/NFPA 31 Installation of Oil Burning Equipment, latest revision.
A. Checking Chimney
The chimney is a very important part of the heating system. No boiler, however efficient its design, can perform satisfactorily if the chimney
serving it is inadequate. Check chimney to make certain it is the right size, properly constructed, and in sound condition.
Table 3—Boiler Rating Information
BOILER MODEL BURNER FIRING RATE (GPH) INPUT (MBH) TANKLESS RATING (GPM)
BW4BAH091 BW5BAH091 0.65 91 2.90
BW4BAH105 BW5BAH105 0.75 105 3.00
BW4BAH140 BW5BAH140 1.00 140 3.25
BW4BAH126 BW5BAH126 0.90 126 3.15
BW4BAH175 BW5BAH175 1.25 175 3.50
BW4BAH210 BW5BAH210 1.50 210 3.75
BW4BAH168 BW5BAH168 1.20 168 3.45
BW4BAH245 BW5BAH245 1.75 245 4.00
BW4BAH280 BW5BAH280 2.00 280 4.25
*Gallons of water per minute heated from 40°Fto140°F with 200°F boiler water temperature, intermittent draw.
IN
1
⁄2 IN. NPT
3
⁄4 IN. NPT
CONTROL WELL
A95596
Fig. 7—Tankless Heater Coil
TEMPERED
HOT WATER
UNTEMPERED
HOT WATER
(TO AUTOMATIC
DISHWASHER, ETC.)
SHUTOFF
VALVE
COLD WATER
INLET
IN
OUT
TANKLESS COIL
LIMIT
CONTROL
CENTER LINE
OF COLD TAP
8 IN. TO
12 IN.
TEMPERING
VALVE
A98269
Fig. 8—Recommended Piping with Tankless Heater Coil
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