HVAC PROTech® Forums

ServiceF1rst

Smart Valve Gas Ignition System Overview

• All Smart Valves eliminate the need for a separate device, remotely mounted, that contains the electronics necessary to control the sequencing of the pilot, the main gas burner and flame sensing circuit. All of these functions take place in the valve’s operating head.

• Each of the many varieties of this Smart Valve system use flame rectification for flame proving .

• All of the system’s electrical wiring occurs on the valve’s top using Amp-type electrical connectors to plug in to receptacles on the valve (except on Generation I systems, which have the 4-pin power receptacle located on the valve’s gas outlet face).

• All of the different low voltage systems use Norton’s 24 VAC type silicon nitride igniter. This igniter has a low starting resistance to current flow and it heats to the temperatures needed in +/- 2 seconds. As its temperature rises its resistance increases.

• Smart Valve systems that use line voltage igniters require Norton igniters that need from 7 to 17 seconds for proper warm-up prior to allowing main gas to flow. These igniters are a version of silicon carbide. These have a higher initial resistance to current flow but it reduces as it heats .

• All valves (with exception of Generation 1 valves) have an electrical on-off switch located on the valve’s top . This interrupts current flow to the valve’s pilot and main gas valve. It is also the replacement for the older style units that utilize gas rotary shut off gas cocks .

• These systems are not suitable for equipment retrofit on older appliances. They can only be applied by the appliance manufacturer.

• These systems have a maximum gas capacity of 415 cfh - depending on the valves inlet and outlet sizes. It is important to note the valve’s capacity must be reduced by 5% if a screen-type filter is used in the outlet of the valve .

• Basic versions will provide a communications link to the equipment 's electronic fan timer to start the "Start-On delay and Fan-Off delay" timings. This signal is provided through a 16 VAC signal to the EFT carried by a lead in the 4-pin plug that supplies the 24 VAC power to the valve from the EFT.

These are but a few of the unique system properties that must be understood by your technicians so that they may provide excellent service to your customers that own equipment with Smart Valves "
_________________

Of all the instruments utilized in the HVAC/R trades - I trust analog gauges the least.