Spec # 15#-STM – 5/14/1999

MISC. SPEC ADDS FOR 15# STEAM BOILERS

Stack Outlet

Each boiler will be furnished with a " diameter motorized stack outlet damper. The damper will open on a call for heat and close on the off cycle. Unit will be furnished with a damper open proving switch interlocked to the burner circuit. In addition, unit will be furnished with a 3" diameter stack thermometer.

Draft Control System

Boiler package to include a Cleveland "9500" series self contained solid state draft controller with a 4" diameter compound draft gauge, a low draft proving switch with ignition delay relay, and a 3" diameter stack thermometer. System will include a " diameter stack damper, heat resistant bearings, sampling tube and all necessary hardware to form a complete draft control system, mounted, wired and tested at the boiler factory.

Modulating/Boiler Lead-Lag

Contractor shall furnish and install a Heat-Timer MOD-4 sequencing control panel. Panel will be designed to sequence and modulate the firing sequence of up to four boilers. Operation will be designed for fixed or automatic rotation of boilers, including a manual-off-automatic selector switch for each boiler. The panel will be designed to be enabled/disabled by a building management system or an outdoor air temperature sensor. Panel will be complete with all necessary relays and a 0-30# system pressure transducer. This is a wall mounted panel requiring mounting and wiring by the installing contractor.

(On-Off and Low-High-Low)/Boiler Lead-Lag

One L.E.S. Inc. Model Sc-DP sequencing control panel designed to sequence 2-5 steam boilers with start delay timers, push button programmer, an adjustable deadband and digital readout display. Package will include a 0-30# steam header pressure transducer. This is a wall mounted panel requiring mounting and wiring by the installing contractor.

Modulating Feedwater Train

Each boiler will be furnished with an electric type modulating feedwater control system, with a McDonnell & Miller 193-7B combination feedwater controller and primary low water cutoff. (In lieu of standard M & M 157 controller) A motorized stainless steel feedwater valve with a spring-return proportional actuator. The valve will include a manual-automatic selector switch and a manual potentiometer. The potentiometer will serve as a hand control in the manual position and as a hand control in the manual position and also as a high end trim potentiometer in the automatic position. The modulating control system will receive 110 volt 1 phase power supply from the burner control cabinet. The system shall be mounted on the boiler to include a 3 valve by-pass with a globe valve and a feedwater stop-check valve. The complete system shall be mounted, piped, wired, and tested at the boiler factory.

On/Off Feedwater Train

An on/off, zero differential solenoid with inlet Y strainer, (strainer portion of valve to be furnished with a ball valve piped to the side of boiler for flushing the strainer) a 18" high air chamber located at inlet of solenoid, two isolating shutoff valves with a union for servicing the strainer, by-pass valve, solenoid and swing type check valve. All mounted, piped, wired and tested at the boiler factory.

Analog Type/Conductivity Controller

One Pulsatrol Model ABC-101 boiler conductivity T.D.S. controller. A NEMA Type 4X enclosure. Control panel will include a dial type set point and calibration adjustment. Panel will have LED's to indicate "blowdown cycle," "alarm" "power on" and a relay test switch. Unit will include a model VP-100 surface blowdown package consisting of a ½" orifice union, 316SS orifice cup, electrode and a ½" solenoid valve for an automatic timed sample and blowdown operation. Complete package to be mounted, wired, piped and tested at the boiler factory.

Alpha-Numeric/Conductivity Controller

One Pulsatrol Model MBC-210 boiler conductivity T.D.S. controller using advanced microprocessor technology. A NEMA Type 4X enclosure with alpha-numeric display of T.D.S. level for the boiler. Control panel will include a clearly labeled keyboard, fully isolated inputs with high resolution and adjustable sensitivity. Unit will include a model VP-100 surface blowdown package consisting of a ½" orifice union, 316SS orifice cup, electrode and a ½" solenoid valve for an automatic timed sample and blowdown operation. Complete package to be mounted, wired, piped and tested at the boiler factory.