Help!!! Gas solenoid

Jay_23

Help!!!! When my gas fired steam boiler fires up ,a loud humming sound comes from the gas solenoid valve. It goes away after a while. Boiler seems to be operating okay. Do I have a problem? Anything to worry about?

Empire_2

Hello Jim:

Besides being nosey, No there is not much to worry about. Just like a contactor that has an actuator arm which is powered by a lo voltage coil, if dirt or dust builds on the armature, the coil in either begins to humm, or buzz. It is quite impractical to take apart and clean, and replacement is the logical solution. Also, could be some kind of obstruction that is not allowing the plunger inside your solenoid not to fully travel open......

My .02

Mike T.

Chris_82

replace ASAP, it will eventually rupture the valve, if the valve was manufactrued after (I forget the date, but) older gas valves with this problem should be imediatly condemmed and shut off, they leak, the newer valves are sealed, but still should be replaced asap, most every gas company has generic valves for this purpose.

Techman

Gas Valves

I agree w/ Mike T.But if Chris say's the gas valve will leak ,then I'd side w/caution.Chris,all valves will leak? Something new to me , but I'm here to learn ,as well!

Empire_2

Dave......

You crack me up.......:-) I'm not only hungry from you last post, but now I can't eat cause I'm laughing so hard..:-)

Mike T.

PS Chris: Info you gave is interesting. I have no knowledge of a rupture in a solenoid type of valve.....They are in cased in a housing, but I will head you comment.:-)

Hi Terry,...Have a HAPPY NEW YEAR...

Mike T.

realolman

Does it operate from a thermocouple?

Jay_23

gas solenoid

Yes operates from a thermocouple.

Techman

Which is it?

Hi Jim, I'm a little confused here. Are you talking about a "solenoid gas valve" or a "main gas valve"?

realolman

nothing more to say

as anyone who reads my posts knows, I am no expert at all. I am here to learn. In light of Chris' post, I am not going to comment further. He seems sure of himself.

Gas man_7

gas valve noise !

Most likely needs replacing , sooner than later ! Did you happen to check the voltage ! Should be 24v ,I've seen noise from valves when this varies. Happy New Year to all !

Jay_23

solenoid gas valve

Yes, It's a White-Rodgers Type 2509 solenoid gas valve 25v Presure rating- 1/2 psi. Instructions say it's used to control the flow of gas to the main burner under command of the room thermostat. I'ts only a few years old and the thermocouple was replaced recently by the local utility co. Don't want to call them if I don't have to. Thanks for your help.

Chris_82

Some of these valves are 24 volt, and the voltage can be low enough to cause this humming, clacking, what happens is: the solenoid, and not all operate with a solenoid, has enough current to pull the valve but when the iron slug changes the inductance of a coil it requires more current which it doesn’t have and it slides back to the start position, and then this cycle starts again, causing the humming. Some of these mill-volt valves use a rocker assembly but the idea is the same. The valve gets 24 volts elsewhere and can be confused with true mill-volt equipment. If it is 24v valves then replace it…if it is 24 v then sometimes the wires to the thermostat should be cleaned of oxidation to see what happens. These combo valves are not common.
If it is a true millivolt system, clean the wires as a first step, if it is a millivolt system you shouldn't worry about the valve leaking because these newer, post 1960? (high-tech) systems were manufactured to a different standard than the older gas valves that have the potential to leak. A true millivolt system uses a small wheel/ generator to power the valve, like a hamster in a cage; they are very common in gas fireplaces, conversion refrigerators, and some other popular appliances that have remote accessory thermostats, unlike gas water heaters which use a bimetallic strip near the heat source, generally if you have an appliance like a gas fireplace that is not connected to an electric plug or 120 v it uses a millivolt generator to open the gas supply, handy for propane devices in the woods or a remote camp. Unfortunately it still will need to be replaced, but generally they last a life time. I have run into problems with some techs, with fireplaces in bedrooms, most codes require a thermostat for a gas appliance in a bedroom, and when mr. not so helpfull can't get 24v at the thermostat and pronounces the fireplace has a blown fuse, well it's difficult to measure the millivolt output with a meter anyways... Sometimes gently tapping the valve will get the wheel spinning again, but I have noticed this to be a temporary solution. And you might try cleaning the pilot orifice at the lit end, sometimes this also helps, but in past conversations if the pilot is lit the manufacturer generally considers this enough flow for the valve to function. I hate to say something like play with the pilot adjusting screw, because most small pilot systems don’t have an testing port to set to something like .oo something, but play with the pilot and see what happens.

Unknown

If it is a 24 Volt

solenoid valve and it is humming, try reversing the wire connections, that has worked for me for the last 46 years, 28 of those working for a gas utility as a service tech. The last 18 as owner operator of Gas Training Institute. If that does not work replace the valve. I suggest if replacing to do a complete gas manifold change to a combination gas control.

Chris_82

I didn't catch this when I first read this...

If it is operating from a "pile" type thermocouple, then change the thermocuople if cleaning the terminals dosen't work. If either of these two don't work then change the valve, not much else to do. The following web site is a brief primer but not inclusive of all the designs out there. http://www.freepoolheat.com/gassystem.html#millivolt

If you were technicly inclined a low millivolt reading less than 250mv can also under certian circumstances cause this, you should read 300 plus mv at the thermocouple terminals, if it is around 250 or less it can run, but it may switch the main valve on and off, enough to cause humming...again the termocoulple as a first step.

If thats not enough...sometimes the pilot being adjusted too high, helps with draft problems and some universal type replacment piles...more heat more millivolts, but if excessive this can cause premature failure of the pile.

next...I'm not clear which 2509 you have, but the 24v needs to run through the pilot cir., the thermostat, and possibly a limit control, if the transformer is weak...too low a current this can also cause the soft-touch selonoid to vibrate. So can some of the new capacitor driven digital thermostats, these are the programmable t stats that do not have a battery! They can alternate between off and on very rapidly, what happens is the set point, the temp you set the tstat to, dosen't have any range, or sometimes called span...litlerally the tstat will turn off and on at one temp rapidly, it will vibrate at what you have set it to. The early replacment round honeywell d86's did this, do you have one of these? And a 2509...depending upon which model you have will leak!

Ken D.

Humming

It doesn't know the words? (Sorry, I couldn't resist). Why take a chance? Replace it.