Boilers With Tankless Heater Coil; Installation-System Piping - Carrier BW4 Installation, Start-Up, And Operating Instructions Manual

Oil-fired cast iron hot water boilers sizes 74,000 through 239,000 series a

Table of Contents

Boilers may be factory packaged with a tankless heater coil.

The use of this coil eliminates the need for a hot water storage tank. Instantaneous heating of water in coil provides a flow of hot water for domestic

use if proper burner and water supply line controls are used.

IMPORTANT: Do not use a tankless coil if water is excessively hard with lime or other deposits which will accumulate inside coil.

PROCEDURE 1—MOUNTING AQUASTAT CONTROL

The control configuration on this boiler has been set up so that the Honeywell L8124C Combination Hi/Low Limit Aquastat Relay mounts on the

tankless coil. This maximizes tankless coil performance by making burner respond more quickly to a call for domestic hot water.

The boiler is completely wired according to schematic wiring diagram. (See Fig. 13.) The installer must mount the L8124C Aquastat on control

well in 3/4-in. tapping on tankless coil. (See Fig. 6.)

PROCEDURE 2—TANKLESS COIL PIPING

Piping is as shown in Fig. 7. A tempering valve (mixing valve) is recommended.

⁄

IN. NPT

⁄

IN. NPT

CONTROL WELL

Fig. 6—Tankless Heater Coil

1. Place boiler in selected location as close to flue as possible. (See Fig. 3.) Boiler is shipped assembled. Only the factory-supplied relief valve

need be installed.

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 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. 8, 9, and 10.)

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. (See Fig. 10.)