Rehab a heater with 24 volts and stage2 valves

you are dropping voltage, there is either a worn or some load across lines. You go and buy enough doorbell wire and disconnect wires at transformer and run thet wires to unit. I also would check at xfmr the voltage when it calls for valv to open, if drops replace the xfmr.

Most of the humidifiers are run by 24 volts AC. disconnect the power wire to stat on circuit board and check there with meter and connect to low voltage ground for 24 volts, I'm assuming the two wires that power the humidistat are red and white.typically red is used for power. most likely you have power if the red for the stat is connected to the W on the board and the heat works, but the humidifier only works while heat is on.the next thing in line is the humidistat , it's a switch so if there is only two wires going to it take them off the stat and connect together, if furnace is on heat and running and stat wires are connected it will send power to water solenoid, if its not working yet the problem lies in the water solenoid if you have 24 volts at the two wires at solenoid.check while disconnected, do not connect those two wires together or a 3 amp fuse will blow on the furnace board. if you have 24 volts there then the valve may be bad or the valve may be stuck or clogged, loosen water supply line to make sure water is getting to valve. I spent many years working in the HVAC industry.

Need to check the low voltage circuit for 24 volts, the 480 volt to 24 volt transformer may have a circuit protection reset or fuse installed. All the 3 phase electric heaters use a low voltage control circuit for operation of relays (24 volt coils).

The system is 24 volt AC so start by checking the voltage from the transformer to make sure it is approximately 24 volts AC. The current will flow through the humidistat when continuity is made at the control as the humidistat senses that your house needs moisture. Disconnect the wires from the himidistat and set it to a high level, you should hear a click on the way up. With the 24 volt wires disconnected, check for continuity with a volt meter. If you don't have continuity replace it. Current also flows through an inductive sensor switch that hang on a wire from the blower. When the blower wire has current flowing through it, the switch senses that an closes makin the connection. With both wires disconnected from the 24 volts you can test for continuity when the blower is running. Overall, this is a continuous circle of wiring and is not directional like DC so think of the wiring a a big loop. The correct current has to flow through the transformer, through the humidistat, through the blower switch, through the solenoid completing the the circle before the solenoid will activate. Hope this helps.

If you're wiring up 120 volts to the primary then you need to connect H1 and H3 together, then connect H2 and H4 together. Then connect one side of line (120 volts) to H1 and H3 and connect the other side of line (120 volts) to H2 and H4. Then for the 24 volts secondary X1 is one side of your 24 volts and X2 is the other side of your 24 volts.
For 240 volt primary connect H2 and H3 together, Then connect one side of your Primary (240 volts) to H1 and connect the other side of your primary (240 volts to H4. Then your Secondary 24 volts is still X1 and X2.

What kind voltage is the heater operating on, 24 volt or 750 millivolt? If it is 24 volt check the transformer & thermostat for 24 volts along with gas valve, if it is a 750 millivolt system check the 2 wires coming from the pilot burner area for 750 millivolts, if you have a wall mount thermostat, tie the two wires together and see if main burners ignite, if they do replace thermostat. I really need more info to help you more, this unit came with two types of gas valves, a 24 volt & a 750millivolt type check name plate on unit to see which one you have.

if you can use a meter check for 24 volts at the valve when you call for heat. If you have 24 volts and no burners then the valve is bad, if you do not have 24 volts then another safety is locking out the valve

I think you mean a milli-volt system. I went to the cozy heaters website and found the wiring diagram in an owners manual for a similar unit, a W355. I bet the wiring diagram will work for your.

whoo tall order! well, since that unit uses a piezo crystal spark gap that's half the battle. go to the grainger site and find a 24 volt electrically operated solenoid for gas use. anything else won't do. next go to the white rodges web site and find a spark igniter with a flame rod flame detector 24 volt. you'll also need at least a 500va 120/24 volt transformer. a standard honeywell stat will do. I'm thinking the unit uses a millivolt generator to keep the gas valve open. you could substitute a mercury button cell to energize the pilot valve and keep the valve open. give me your email addy and I'll see if I can draw up a diagram for you.