Weil-McLain CGA25SPDN manual 3d Piping low temperature systems, Temperature gauges

GOLD CGa Gas-Fired Water Boiler — Boiler Manual

3d Piping — low temperature systems

Primary/secondary (preferred) Bypass piping method

0RIMARYSECONDARY bypass piping is preferred because the flow rate and temperature drop in the heating circuit(s) is determined only by the heating circuit circulator(s). So adjustment of the bypass valves in the boiler circuit will not cause a change in the heating circuit rate and temperature distribution.

Figures 13 and 14, page 21, show suggested bypass arrangements using PRIMARYSECONDARY bypass piping (preferred) for low temperature systems such as RADIANT HEATINGTSYSTEMS or CONVERTEDEGRAVITY SYSTEMS. For alternatives, see pages 22 through 25.

The bypass valves (items A and B) provide mixing of hot boiler outlet water with cooler system return water

—set to assure a minimum return water temperature (at least 130°F) to the boiler. Set the valves as explained below.

Temperature gauges

'AUGEUA is suggested, but optional on any system.

'AUGEU B is optional on converted gravity systems, but REQUIRED on radiant heating systems — to display

the water temperature being supplied to the radiant tubing.

'AUGEU is REQUIRED on all systems to assure the return water temperature is accurately set for a minimum of 130°F. If this gauge is not available however, adjust the valves such that the boiler-mounted temperature/pres- sure gauge reads at least 150°F when the system return water is cold (approximately 60°F water temperature).

Valve adjustment (Figures 13 and 14 only)

1.Set the valves while the system is cool, setting for the coldest expected water temperature (usually 60°F since the system will often drop to room tempera- ture between cycles).

2.Start with valve A fully closed and B fully open.

 'RADUALLYUOPEN VALVELA while closing valve B until the temperature at gauge  reads 130°F when gauge A reads 60°F.

 .OTE THAT VALVELA regulates the amount of hot wa- ter from the boiler supply which mixes with return WATER 6ALVELB regulates the amount of system water flowing through the boiler secondary loop.

Failure to PREVENT LOWWRETURN WATERTTEMPERATURE to the boiler could cause corrosion of the boiler sections or burners, resulting in severe personal injury, death or substantial property damage.

Radiant heating system piping should include a means of REGULATING THEHBOILER RETURN WATERTTEMPERATURE and the SYSTEM SUPPLYYTEMPERATURE (such as provided by an INJEC

TION PUMPING CONTROL).

"OILER RETURN WATERTTEMPERATUREAWILL BE ADEQUATELY CONTROLLEDEUSINGITHEGMETHODSESHOWNE in this manual provided the SYSTEM SUPPLYYTEMPERATURE is RELATIVELYYCONSTANT

DO NOT apply the methods of this manual if the system is equipped with an OUTDOORD

RESETSCONTROL Instead, PROVIDE CONTROLSLAND PIPING which can REGULATE THE BOILERTRE

TURN WATERTTEMPERATURE at NO LESS THAN —& regardless of system supply temperature.

#ONTACTTYOUR 7EIL-C,AIN REPRESENTATIVECFORASUGGESTEDEPIPING ANDDCONTROLNMETHODS

Failure to PREVENT COLD RETURN WATERTTEMPERATURE to the boiler could cause corrosion damage to the sections or burners, resulting in possible severe personal injury, death or substantial property damage.

20 Part Number 550-101-009/0107