Technical Service: Steam Valve Rebuild

WARNING: The video depicts a service job intended for a trained service technician. Do not attempt this on a hot machine. Failure to turn off machine may result in severe injury! Unplug your machine before removing any body panels. Failure to cut power to the machine may result in high voltage shock or other severe injury! Any users performing this service should exercise extreme caution. If you have any questions regarding this service, please contact your distributor, a service professional, or Synesso, Inc.

Today we will be looking at a steam valve rebuild and why you would rebuild a steam valve. There are three reasons to rebuild a steam valve. One would be if water or steam is dripping from the tip of the steam wand. The second would be if water or steam were coming from around the ball here at the top of the steam wand retaining nut. And the third would be if water or steam were coming from behind the handle where the handle presses the stem into the valve.

Caution: Working on a steam valve should only be done with the machine unplugged, the steam gauge with no pressure at zero, and the machine cooled off so that you do not get burnt while you are doing this procedure.

To do the rebuild of the steam valve, you need:

  1. Food-grade lubricant (we recommend Super Lube)
  2. Steam valve rebuild kit (Synesso part no. 1.7320)
  3. A very small, slotted screwdriver
  4. A pair of pliers
  5. 5/8” crescent wrench
  6. Regular slotted screwdriver

The rebuild kit contains the O-rings, steam seal holder and gasket, and small bits that go inside. If you need to install the rubber gasket (the seal inside the steam valve) in the holder, there is a little bit of a trick to it. Press it in with your fingers and notice it does not sit flush because it has air trapped behind it. If you take a very small screwdriver and slide it in between the rubber and the valve body and press down, then you can get it in there nice and flat.

The first thing that we need to do is remove the sheet metal: the top housing, side panel, lower front panel and drain tray. Locate the steam valve isolation ball valve and turn the handle 90 degrees to the tube to turn the steam off. This isolates anything past the valve. The next step is to remove the steam wand with a 5/8” crescent wrench, revealing a spring on top of the valve that provides the tension against the steam wand ball to keep the wand from moving freely.

We will now disassemble the steam valve; first disconnect the steam tube from the steam valve and loosen the fitting on the other side of the tube. The back of the steam valve unscrews next (be careful not to lose the spring inside!), then the stem/pusher (with two O-rings on it) can be pulled out the opposite way. To retrieve the internal steam seal holder and gasket, push a very small screwdriver through the steam valve towards the interior of the machine. At this point, you can reach into the steam valve and feel the surface of the seal to make sure that there are no pits or gouges in the face of the seal. It should feel nice and smooth when you drag your fingernail around the end of that seal. There is nothing more to do on the steam valve itself, other than inspect for any kind of grit or debris that needs to be removed.

Now we can remove the original Teflon gasket from the steam valve nut (this sometimes takes a little bit of force to get it to come apart) and replace the new Teflon gasket back on to the steam valve nut. To reinstall, place the new steam seal holder and gasket back inside the valve (orientated so the gasket points away from the machine). Next, insert the spring carefully between the cup of the seal holder and the steam valve nut and spin the back of the valve together. We want to smash the Teflon gasket in there flat, so make sure the steam valve nut is nice and tight with the valve body. The steam valve tube now goes back on the valve body; hold the nut on the steam valve and tighten the tube at the top, then hold the nut on the steam valve isolation ball valve and tighten the tube at the bottom.

The next step on the steam valve pusher/stem is removing the old O-rings and replacing with the new ones. Use a small amount of food-safe grease to lubricate the O-rings, then very gently re-install the pusher being careful not to chip up the O-rings and then double check that the pusher presses in and out nice and smooth. If it hangs up, or if the spring is binding, you may have to take it back apart to get the spring in the cup of the seal correctly.

To put the steam wand back on, replace the Teflon gasket under the steam wand nut. The gasket has a smooth side and a sharp side, so ensure the gasket is installed with the smooth side facing up towards the wand. The spring goes back in the top of the steam valve first, then we will add a little bit of lubrication on the steam wand nut threads before reinstalling the steam wand on top of the spring. (There’s some downward force required to get the threads to start.) The Teflon gasket needs to be crushed similarly to the valve body gasket, so we need to get it tight. Hang onto the valve to gain leverage and twist the wand in so that you are getting a good smash on the Teflon gasket.

TIP: When installed correctly, the steam wand ball should turn nice and easy, and the wand should stay in position.

When reinstalling the side panel put a small amount of lubrication on the end of the valve pusher/stem and put the side panel back on. Tighten a single side panel nut at first and make sure the steam handle/hub has a little bit of play with smooth travel across the steam valve before reinstalling the remaining side panel nuts. The rest of the body panels go back on in the order they came off.

That is rebuilding your steam valve!

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