Shower Has Hot Or Cold Water Only?
Do you have a shower that only runs hot or cold water no matter how you turn the handle? There may be several causes for this issue including a cutoff supply line, a broken handle (spins freely), or a faulty valve cartridge. If you've checked the water supply, made sure the shower handle is working properly, and you've checked or replaced the valve cartridge and your shower is still stuck supplying either hot or cold water only, you may have an issue with your shower's balancing spool.
What Is A Balancing Spool?
Okay, you've narrowed down the water temperature issue to possibly be the balancing spool. But what exactly is a balancing spool and what does it do? Basically, the balancing spool is a device inside the shower valve that should regulate the shower's water temperature when the supply water pressure changes. For example, if someone flushes a toilet when the shower is running, the water temperature is kept constant by the balancing spool.
Not every tub/shower valve will use a balancing spool but manufactures such as Moen, Delta, and American Standard can use them. If in doubt if you have a balancing spool, you can try checking the manufacture's specification for your shower valve. Alternately, you can remove your shower valve handles and faceplates and take a look. In order to check to see if the balancing spool is the issue with your water being stuck either hot or cold, you'll have to remove it for inspection.
Steps To Access Balancing Spool
In order to access the balancing spool, you'll need to remove the shower valve handles and faceplates. The following shows the steps to remove a balancing spool for a Moen shower valve.
Tip: Before you start, cover your floor drain to keep any dropped screws or other removed small parts from being lost!
Moen Shower Valve
The first step for gaining access to the balancing spool is to remove the shower handles. Each manufacture and model could be different but many have a set-screw that is removed to take the handle off.
Remove Shower Valve Handles - Use Allen Wrench For Set Screw
Moen Shower Valve With Handles Removed
Continue the disassembly removings, screws, stop bodies, and any other valve components until the main value body is exposed.
Moen Shower Valve Faceplate Removed
After all the surface components are removed, the main valve body and the balancing spool top can be seen. The balancing spool top is shown below (yellow arrow). At this point you will only be able to see a large circular disc with with what looks like a flathead screwdriver slot. This is only the top of the spool and the rest of the device is embedded in the valve body.
Example Moen Valve Body and Balancing Spool Location
Removing Balancing Spool
Note: If you haven't turned the water supply off yet, do it now.
First, turn the hot and cold water supplies off. The Moen valve body shown here has local shutoffs that are operated with a flathead screwdriver. Turn each one to the off position. Alternately, you can use the main shutoff valve in your house to turn off the shower hot and cold water supplies.
Removing the balancing spool can be challenging especially if its been in place for years. Ideally, you could take a flathead screwdriver and just turn it out counterclockwise to release the screw threads on the spool. But, you will likely find the screwdriver will not have enough purchase and will slip or pop out before the balancing spool loosens.
If simply using a screwdriver is not working, you have a couple options. Many have made a custom removal tool by grinding down a chisel or similar tool so the tip fits tight in the entire width of the balancing spool slot. That way, you'll have a better chance to torque the spool loose before the tool slips out or strips the slot. This can work but you'll need to make a special tool for this one job.
Another option is to use a standard flathead screwdriver and a hammer to tap the spool loose. Care must be taken not to tap too hard which can damage the balancing spool (or valve body). Start with gentle taps alternately between the far ends of the balancing spool screw slot. Tap in the direction that will move the balancing spool top disc counterclockwise. Eventually the spool should loosen to the point where you can use the flathead screwdriver normally to fully unscrew the spool.
Tap One Far Side Of Balancing Spool Slot With Screwdriver Using Hammer To Turn It Counterclockwise
Tap Other Far Side Of Balancing Spool Slot Screwdriver Using Hammer To Turn It Counterclockwise
Once Loose, Finish Removal Of Balancing Spool With Screwdriver
Removing Balancing Spool
Check Balancing Spool
Finally, the balancing spool is removed! But it is bad? Is it causing your hot or cold water to be stuck in one position. There's an easy way to check. Take the balancing spool and shake it in the direction along its long length. You should hear a rattle back-and-forth when you shake the spool. Here's video showing you what a good balancing spool should sound like when shaken.
Sound Of A Good Balancing Spool
If the balancing spool does not rattle when shaken, congratulations, you find the issue with your shower!
Recondition or Replace Balancing Spool
At this point, you have two choices - either recondition your current balancing spool or replace it with a new one.
If you want to attempt reconditioning your balancing spool, simply soak the spool in a solution of half water and half vinegar. Let it soak for at least 10 minutes. After the soak, rinse the spool well with clear, clean water. Now check the spool and give it a shake to see if it's now working. If so, you could replace the spool and be done with the project.
Alternately, replacing the balancing the spool is a good option. A new spool may give you a little longer life but it comes with the cost of purchasing a new one which will set you back somewhere between $40 and $80. Make sure to replace the balance spool with a compatible spool for your shower valve. You can find many replacement options on Amazon or plumbing supply store.
Putting It All Back Together
You took everything apart, so reassembly should be easy. Just reverse the steps you made for disassembly. Start with replacing the balancing spool. Continue on replacing everything as it was. Do a final check and make sure both hot and cold water are now both working. Done!Keep It Working
The balancing spool most likely stopped working because of mineral deposits. You probably can't do much about that. One thing you can do is to turn the shower on occasionally if it is a rarely used shower. So once every week or so if the shower has not been used, turn the water on and switch between hot and cold a few times. This should help to keep mineral deposits from building excessively.