Weil-McLain CGA25SPDN manual BOILER-bypass piping method, Valve adjustment

GOLD CGa Gas-Fired Water Boiler — Boiler Manual

3d Piping — low temperature systems (continued)

BOILER-bypass piping method

This piping method (&IGURE  or , page 23) is called a BOILERBYPASS because part of the circulator flow is bypassed around the boiler (through valve A). This method reduces the flow rate throughout the boiler, in order to raise the average water temperature in the boiler ENOUGH TO PREVENTVmUEUGASACONDENSATIONS"OILERBYPASS

PIPING IS EFFECTIVECFOROSOME BOILERSL ˆINCLUDINGUTHEH#'A

—provided the flow rates are adjusted according to the instructions following.

&IGURESU and  are alternative piping suggestions for CONVERTEDEGRAVITY (large water content or steam systems) or RADIANTIHEATINGTSYSTEM — for use when primary/secondary piping can’t be applied. (&IGURE , page 25, is another alternative, using system bypass in place of boiler-bypass piping. &IGURE  however, is not suitable for radiant heating applications because it does not protect the radiant system from possible high water temperature.)

"OILERBYPASSPIPING KEEPSESYSTEM mOWORATE AS HIGH AS possible and temperature drop as low as possible, help- ing to equalize the building heat distribution.

Temperature gauges

'AUGEU A is optional if the bypass valves will be ad- justed using cold (or room temperature) return water

to the boiler. (When setting the valves without gauge A installed — using cold or room temperature water

—assume the return water temperature to be 60°F. Set the valves so gauge  reads at least 120°F.

'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 reliable adjustment of the bypass valves. The boiler-mounted temperature/pressure gauge can be used if a separate temperature gauge is not installed.

Valve adjustment

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

 'RADUALLYU OPEN VALVEL A while closing valve B until the temperature at gauge  reads 60 °F higher than gauge A. A minimum 60°F temperature rise through the boiler assures a low enough flow rate and high enough average temperature to prevent condensation even with low system return water temperature.

 6ALVELA regulates the system flow rate, while valve B regulates the boiler flow rate.

4.The boiler-mounted temperature/pressure gauge may be used in place of a separate gauge .

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.

22 Part Number 550-101-009/0107