Draft Range Transmitter Assembly
The Model JC-22XMTR Draft Range Transmitter Assembly is a field mountable boiler draft range transmitter and independent high pressure cut-out switch with a 5 second time relay.
- Overview and Features
- Application
- Specifications
- Documents
The Model JC-22XMTR Draft Range Transmitter Assembly is a field mountable boiler draft range transmitter and independent high pressure cut-out switch with 5 second time delay relay. The transmitter provides a 4-20 mADC signal for draft control and the time delay relay provides an isolated “High Pressure Cut-Out” contact for use in the Flame Safeguard Limit Circuit. The time delay feature helps avoid nuisance burner shutdowns due to momentary draft fluctuations. The transmitter is calibrated as +1"wc = 4 mA to provide fail-safe operation (damper opens).
- -1" W.C. to +1" W.C. Draft Transmitter Range
- +0.15" W.C. to +4.0" W.C. High Pressure Cut-Out Setpoint (field adjustable)
- 5 Second High Pressure Cut-Out Time Delay Relay
- Combination Draft Range Transmitter, Independent High Pressure Cut-Out with 5 second time delay relay in one box and a single draft connection saves installation cost
Furnace draft is typically a low range signal, and contains a great deal of pulsation and vibration. The JC-22XMTR draft transmitter is specially designed for furnace stack draft applications to filter this noise. Ordinary low range transmitters do not include this noise filtering.
The usage of the High Pressure Cutout (HPCO) versus the Low Draft Cutout (LDCO) is determined by the burner and boiler design. LDCO describes when the burner trips on a flue gas pressure rise above a negative cutout setpoint (i.e. -0.05” wc). HPCO describes when the burner trips on a flue gas pressure rise above a positive cutout setpoint (i.e. +0.05” wc). In both cases, the burner trips when the pressure rises. The difference is whether the cutout setpoint is negative or positive.
LDCO Usage
Atmospheric burners and older induced draft burners that rely exclusively on the negative pressure at the boiler outlet to suck the air and flue gas through the boiler. These systems require a negative pressure setpoint and the Model JC-22XMTR-LDCO.
HPCO Usage
Forced draft burners have a burner fan that generates positive pressure to push the air and flue gas through the boiler. These systems require a positive pressure setpoint and the model
JC-22XMTR-HPCO even if the draft control setpoint is negative.
If a boiler has a forced draft burner and also has an induced draft fan that creates a very negative draft, then a negative setpoint low draft cutout might be required. Consult the boiler or burner manufacturer.
Enclosure: NEMA 12, Field Mounted
Transmitter
Range: +1" wc to -1"wc
Output: 4-20 mADC (2-wire)
Accuracy: +/- 0.75% FS
Power Supply: 24 VDC
High Pressure (Low Draft) Cut-Out
Range: +0.15" wc to +4.0" wc, Field Adjustable
Dead Band: 0.09" wc (Average)
Contact: 20 Amps/120 VAC +1" wc to –1" wc Draft Transmitter Range
- +0.15"wc to +4.0"wc High Pressure Cut-Out Setpoint (Field Adjustable)
- 5 Second High Pressure Cut-Out Time Delay Relay
- Combination Draft Range Transmitter, Independent High Pressure Cut-Out with 5 Second Time Delay Relay In One Box
- Single Draft Connection Saves Installation Cost
Draft Range Transmitter Specification
Draft Range Transmitter Operation Manual
Draft Range Transmitter Cutsheet
