Selectra electronic gas flame modulation systems: M/MR valves (3.4 kPa inlet), amplifiers, sensors, controllers
Country: Germany · Model: Selectra M/MR
The Selectra electronic gas flame modulation system smoothly changes gas flow with an M or MR valve at an inlet pressure of 1/2 psi (3.4 kPa), and the Series 14 and 44 kits are made for installations up to 30 million BTU/h, about 8.8 MW. It holds temperature without electric motors or mechanically driven throttle dampers, mainly in make-up air units and air heating.
- Valves
- M411, M511, M611, M420(H), M520(H), M620(H), M451, M551, M651 (modulators); MR410, MR510, MR610 (modulator-regulator)
- Valve inlet
- CSA: 1/2 psi (3.4 kPa); a regulator is required before the valve
- Connection
- 3/8"–3" NPT or ISO 7-1
- Temperature
- operation −40…+50 °C; storage −45…+85 °C
Technical specifications
| Valves | M411, M511, M611, M420(H), M520(H), M620(H), M451, M551, M651 (modulators); MR410, MR510, MR610 (modulator-regulator) |
|---|---|
| Valve inlet | CSA: 1/2 psi (3.4 kPa); a regulator is required before the valve |
| Connection | 3/8"–3" NPT or ISO 7-1 |
| Temperature | operation −40…+50 °C; storage −45…+85 °C |
| Series 14/44 | direct heating, make-up air units, up to 30 000 000 BTU/h (≈8.8 MW), setpoint 55–90 °F |
| Series 20/21 | indirect heating, up to four units |
| Other | MX40/MX4010 (with E42/E52/E62 valves, turndown ≈5:1), MP2/MP2+, DFM, signal converters SC11, SC25S, SC30, SC40 |
| Certification | CSA Z21.18/CSA 6.3; UL Recognized (M511, M611) |
Specifications are taken from the manufacturer’s technical documentation. Updated .
Description
The system was developed in 1959 and includes a modulating valve, an amplifier, a temperature sensor and selector, and additional devices. The amplifier sends an output voltage to the valve, which changes the gas supply to the burner continuously and without delay. The modulators M411, M511, M611, M420, M520, M620 (an H version exists), M451, M551 and M651 work with atmospheric and infrared burners and direct heating burners, while the MR410, MR510 and MR610 modulate and regulate pressure at the same time. The body is aluminium, and the connection is from 3/8 to 3 inches with NPT or ISO 7-1 thread. The valve is installed after the pressure regulator, vertically on a horizontal pipe section and downstream of all other devices. In Series 14 and 44 the supply air sensor is mounted in the mixing tube, the standard setpoint is 55–90 °F, any combustible gas is suitable, and dual selectors exist for air curtains. Series 20 and 21 are made for indirect heating in commercial and light industrial air heating with atmospheric burners and control one or several, up to four, furnaces.
How to choose
The valve is chosen by pipe diameter and function, since the MR, unlike the M, also regulates pressure. If the inlet is 5 psi, the MR212 modulator-regulator is needed, described in the EXA series item. The control kit is chosen by the heating layout, Series 14/44 for direct and Series 20/21 for indirect heating. For supply air temperature control there are the MX40 and MX4010 controllers with E42, E52, E62 valves and a two-stage exhaust fan (turndown about 5:1), as well as the MP2/MP2+ controllers and the DFM system.
Request a price and lead time
Selectra electronic gas flame modulation systems: M/MR valves (3.4 kPa inlet), amplifiers, sensors, controllers. We reply within one business day.
Or email office@usk.ua or call +38 (044) 339-50-20.
FAQ
Why is a pressure regulator needed before an M or MR valve?
Per CSA the valve inlet is rated for only 1/2 psi (3.4 kPa), so the mains pressure is first reduced by a regulator.
How is flame modulation connected to an external control system?
For this the range includes the signal converters SC11, SC25S, SC30 and SC40.
What certificates do the M/MR valves have?
The valves are certified to CSA Z21.18/CSA 6.3, and the M511 and M611 also hold UL Recognized status.
At what temperature can the M/MR modulating valves be operated?
The operating range is from −40 to +50 °C, and the valves may be stored at −45…+85 °C.
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