Introduction: GeneralAire Furnace Humidifier Valve Repair
My drip fed GeneralAire furnace humidifier was leaking slowly.
The water feed could come in from either side.
I have three of these valves, all leaking, two of my own and another from a friend who had replaced his, so I had a chance to experiment. A new float valve assembly with valve seat costs around $25.00. I was going to buy a new one, but have time on my hands during this Corona Virus lock down.
4-40 NC tap, pliers, iPad Camera with macro lens, (the chips in the nozzle are hard to see without magnification)
Taig Mini Lathe, Tooth picks, fibreglass 'rod' (to keep track of brass nozzle and keep out epoxy), Sandpaper, medium and fine (to smooth surface of worn valve seat)
Material: Brass tube threaded one end (scavenged from something a long time ago)
Epoxy J-B Weld
Step 1: Cut Brass Tube
Cut the threaded end of the brass tube with lathe. A good tube cutter, dremel tool or fine hack saw would also work. With the lathe I was able to get a clean cut and an approximation of the original bevel.
Step 2: Thread Hole
Using 4-40 NC tap thread hole in valve nozzle to accept new brass nozzle
Step 3: Turn in New Nozzle
Step 4: Epoxy
Mix up JB Weld epoxy and spread around new nozzle. Appearance doesn't matter here, as long as epoxy doesn't go over tip of nozzle.
Allow epoxy to dry overnight.
Step 5: Repair Valve Seat
Make sure the valve seat is dry before starting this part. Sand the dent in the valve seat down till you have a flat surface to ensure a good fit. ( I tried gluing a piece of inner tube onto the valve seat but this made the seat too thick).
Use rubber gloves, the seat will leave a lot of black residue.
Step 6: Reassemble
Put the pieces back where they belong.
There is a small plastic shroud over the valve to direct the flow of water down.
I left out the float, arm, and valve seat to show the nozzle. If you made it this far, you'll know where the pieces belong.
Finally, no more slow leaks.
Question 3 years ago
What is the float made of? Is it solid or hollow? (I'm looking for a material to use in a custom float valve that will be under pressure, so hollow ones won't work.) Thanks
Answer 3 years ago
It is solid. I suspect a more dense version of polyurethane insulation foam. depending on the pressure and supports, I might use styrofoam or whatever the more dense closed cell foam used for some packing is. On another note, the repair lasted for 3 weeks, at which point the old black rubber valve seal became cracked enough at the contact point to allow for a slow leak. The wrinkles and cracks show under microscope. I think the brass nipple is still doing its job, but I haven't taken it apart yet to check.
Reply 3 years ago
OK, got it. Thanks. FYI, I'm not familiar with that brand or type of humidifier. I have this one, which has been rock solid for going on 10 years. No float valve, just a solenoid to turn water on/off. You do have to replace the pads though.