Gas valve with rectifiers

[klubpolo]

Had a service call today on a Carrier roof top M#48TMF012---501HQ. Found unit locked out on failed ignition (gas valve would not open with 24V). Replaced valve and checked operation. OK. The new valve (White Rodgers 36H54) was an excact replacement and came with a wiring diagram that showed rectifiers inside the valve. Does anybody know why there would be rectifiers on gas valve? Also when I removed the common wire from the valve when the Carrier control/ignition board was in the heating mode, the board would lock out on internal fault (8 flashes). This is the valve http://www.partsguy.com/pdf/36H64-463%20INS.pdf

[coolerinfrederick]

probably just a vdc valve

[timebuilder]

Maybe I'm missing something.

Are you saying you are surprised that there are rectifiers in the gas valve?

[syndicated]

Are these rectifiers how slow-open or step-open functions are achieved?

[klubpolo]

Maybe I'm missing something.

Are you saying you are surprised that there are rectifiers in the gas valve?

I tried to ohm out the coil but because of the rectifiers, I guess, it showed open on the multimeter. The valve would click and draw amps but would not let gas through. I never knew gas valves had rectifiers.

[klubpolo]

Are these rectifiers how slow-open or step-open functions are achieved?

Not sure but I'm just curious what's their purpose

[Mike19]

The rectifier is to convert the 24vac to dc current, and the coil inside the gas valve is dc. They call it an "internally rectified coil".

I think some water valves in ice machines are the same way.

[syndicated]

The rectifier is to convert the 24vac to dc current, and the coil inside the gas valve is dc. They call it an "internally rectified coil".

I think some water valves in ice machines are the same way.

I understand the function of a rectifier, I'm just trying to determine its purpose. It seems like for a fast-open valve, there would be no purpose in changing to DC...

[Chuck]

I understand the function of a rectifier, I'm just trying to determine its purpose. It seems like for a fast-open valve, there would be no purpose in changing to DC...

DC is better for solenoids. No chatter or buzz and the solenoid lasts longer.

[Mike19]

DC coil has no inrush when it pulls in. I think they run cooler and draw less current too.

[vahe501]

[QUOTE=klubpolo;14901431]Also when I removed the common wire from the valve when the Carrier control/ignition board was in the heating mode, the board would lock out on internal fault (8 flashes). [/URL][/QUOTE

What is the fault for 8 flashes, should be listed on the cover panel, Do you get 8 Flashes immediately? Or dose the unit try unit fail on ignition consecutive times before the 8 flash lock out?

[valdelocc]

[QUOTE=vahe501;14921141]

Also when I removed the common wire from the valve when the Carrier control/ignition board was in the heating mode, the board would lock out on internal fault (8 flashes). [/URL][/QUOTE

What is the fault for 8 flashes, should be listed on the cover panel, Do you get 8 Flashes immediately? Or dose the unit try unit fail on ignition consecutive times before the 8 flash lock out?

the 8 flashes means "the board kicked the bucket"