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Moen shower faucet provides no cold water, only hot

hot-girl-cold-broken-shower

A common issue with older Moen shower faucets is only cold, or only hot water coming out of the faucet or shower head.  This often happens with showers that are not used very often, or where the water supply is particularly hard or has high levels of contaminants.  If you search the web for help, the most often suggest is to replace the main cartridge (part number Moen 1225 or 1200).  However, this is most likely not the source of the issue.

If you remove the shower faucet knob, and remove the cover behind it, you should see something like the image below.  This is a Moentrol 3570 valve, there are other similar model numbers.

moenvalve

Within the valve is what is called a balancing spool.  This balancing spool valve contains a piston which moves back and forth maintaining a given temperature even if the pressure on the cold side is reduced, for example someone flushes a toilet when the shower is in use.  It prevents a sudden blast of hot water which can lead to burns.  When you suddenly experience only the cold or hot water flowing regardless of where you set the flow handle, this valve is almost always the culprit.

The piston which is inside the balancing spool will get stuck in one position or the other.  When this happens, it essentially shuts off flow to either the hot or cold side.  Poor water quality and age will eventually cause the piston to get stuck in its bore.   The balancing spool (part number Moen 1423) can be seen clearly in the photo below.

moentrol valve

The first step in repairing the balancing spool valve is to remove it.  You will need to use a VERY large screw driver to unscrew the valve (number 2 above).  Make sure you shut off your water first!  You can also use a straight-edge piece of metal clamped in vice grips if you do not have a large enough screw driver.  Spray the outside of the screw with Liquid Wrench or other penetrating oil in advance of your attempt, it can be difficult to loosen.  If you are lucky, the valve will come out with the screw.  But, most likely the top of the spool will separate, like in the photo below.

IMG_5753

If this happens, you will need to retrieve the stuck piece.  The way that I accomplished this was to soak it in Liquid Wrench for an hour before my attempt.  I inserted a screw driver down into the piston and tried to lever it out, tapping with a hammer at the same time.  I then bent a piece of metal rod into a hook shape and fished it inside and caught it against one of the holes in the body of the spool.  Using a pair of vice grips I pulled until it came loose.  This may take some work, so be patient.

Once removed you have two options, replace with a new one, which is not cheap, retail price is between $55-95.00.  Or, you can usually successfully clean the spool.  To do this, remove the round piece of metal at the back of the valve (seen above).  Just slip a small screw driver into the gap and twist it out.  Then tap the piston out of the bore.  I used a socket to support the back of the spool, and used a hammer and screw driver to tap it out.

Next, you want to use fine sandpaper to clean off the piston journals, and the inside of the bore of the valve.  Get aggressive, you want the bore and journals to be polished clean.  Work the piston back and forth in the bore until there is absolutely no sticking or binding.  Then apply plumbers grease and reassemble.  Turn the water back on and test the faucet, you should now have hot and cold water, and just saved yourself a couple hundred dollar repair bill.

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8 thoughts on “Moen shower faucet provides no cold water, only hot

  1. Antonio G

    After reading many other suggestions that recommended change the cartridge, I found out this very illustrative recommendations that made more sense to me. I followed the steps recommended here and the problem is now solved.

  2. Robert

    Wonderful strategy of how to fix a Moen single handle faucet that no longer works correctly – giving only cold or hot water. I had two showers that both suffered this problem after 6 months of non use – they only gave hot water, no cold water. I offer the following tips. Beneath the cap is a large O-ring, so using a powerful petroleum based lubricant (WD-40, Liquid Wrench, etc.) is not needed and counter productive, as it may ruin the O-ring over time. Instead, use a hammer and a large flat head screwdriver to repeatedly tap around the periphery of the cap. Then, use the flat blade like a chisel, place it into the slot of the cap, and begin striking gently at an angle at the slot of the cap, in a counterclockwise direction, as if you were trying to unscrew it with the screw driver. It will move ever so slightly. Keep tapping and when you have moved it about 1/12 turn, you will find that you can easily unscrew the cap the rest of the way by placing the screwdriver into the slot and turning the cap counterclockwise to unscrew it. In both instances for me, the cap and the balancing spool came out together in one piece. I did have to grip the cap with a Vise-grip plier to pull it the rest of the way out of its housing. Once out, if it is in one piece, then don’t take off the top cap. Instead, insert a small flat blade screwdriver into the gap betwen the bottom cap and the body of the balancing spool and gently work the blade around, prying ever to slightly, to slowly pop off the bottom cap without deforming it. With the bottom cap off, you can now use a jewelers flat blade screwdriver to gently prod the piston out through the bottom of the spool housing by gently prying it down from the outside by using the holes drilled into the piston. At some point, you will give up prying it down using the holes on the outside of the piston, and then begin pulling it down by pulling against the holes inside the piston. I used the jewelers flat blade screwdriver for this. Once the piston is about 1/4 the way out of the bottom of the balancing spool, you can grasp it by hand and pull it out. Both my pistons were in excellent shape, and would move freely within the piston bore since there was no corrosion. I used a good silicone (non petroleum based) lubricant to lubricate the piston, and then reinserted it into its bore. Be careful here. I did not measure it with a micrometer to see, but the piston looks totally symmetrical end for end, so be careful to maintain the original orientation and don’t accidentally flip it end for end, because you won’t be able to tell one end of the piston from the other. Once the piston was lubricated and reinstalled into the bore of the balancing spool, I placed the bottom cap back in position and gently tapped it with a hammer to reseat it. Then I applied more silicone lubricant to the threads of the cap and the O-ring beneath them, pushed the spool back into place in the shower valve, and then tightened the cap to where it bottomed out on the brass housing — but did not over torque the cap. No need to, as it relies upon the O-ring for its seal and not torque applied to the threads.

  3. Luke J Doubler

    Hey- Thanks for the post. Was exactly what I needed. Very good instructions and pictures. Was better info than calling the factory. Thanks from Luke Doubler in Minnesota.

  4. Woody

    This just saved me money and a ton of time. Directions were easy to follow and worked as expected. Thanks!

  5. VW

    Excellent advice and technique in the prior suggestions. The photos are very helpful. Apparently it’s fairly common for the brass cap to disconnect from the metal sleeve if the sleeve is stuck while you unscrew the cap, likely from calcium buildup. This is a design flaw Moen should fix but hasn’t in decades. The “break” happened on two valves I had to repair back-to-back.

    There are two types of pistons in the 1423 balancing spool. The older is stainless steel; the newer is plastic. There’s a slight difference in diameter with the SS spool being a little larger, which can impact the ease of removal. Unfortunately both were very difficult to remove. The difference is important because the plastic piston can easily be damaged if you use pliers to grab it.

    Removing the brass screw was difficult but not impossible. Lubricate the threads first and allow time to penetrate. Using a heavy-duty 1 inch chisel as a screw driver, with a crescent wrench for leverage, worked well. The piston in both cases protruded enough that I could grab and pull out with some effort. The plastic piston broke in the process.

    Removing the SS spools was almost impossible and took hours. Overall I spent about 6 hours trying to remove 2 spools in 2 separate valves. There’s not enough lip of the SS cylinder exposed after the brass screw is removed to grab with needle nose. I tried hooks, wires, screwdrivers without success. I finally used a 1/2″ internal pipe wrench (~$11 for a set of 3 @ HD) to help remove the spool. The internal pipe wrench would grab the inside sides of the SS cylinder and finally broke the lime deposits and allowed the cylinder to rotate. With enough rotating and pulling while turning to keep the wrench tight, the cylinder came out enough to grab with needle nose. More pulling and a small vice grip could finally lock onto the lip. There are 3 O rings on the outside of the spool. It’s the resistance of 3, then 2, then 1 that you have to overcome to remove the spool, so it gets easier as each comes out.

    By this point I just wanted the ordeal over. I squirted in Lime-Away, reamed out with a wire brush (used for copper pipe soldering), lubed the O rings with silicon grease, slapped in new 1423s ($65 Amazon), tested and closed up. If I has started with the internal pipe wrench, maybe replacing a stuck cylinder would have taken only an hour. Overall it was a very frustrating experience and annoying because Moen could easily make spool removal a simple process by strengthening the brass/SS connection to ensure it remains one piece during unscrewing.

    Some mentioned cleaning and reusing the old spool. I suppose you can. However, if the spool broke into two parts as mine both did, the SS cylinder part will be very difficult to remove again after re-insertion. After the effort I put into this and hopefully avoiding a future problem, new spools were the way to go.

  6. Tom M

    Procedure and discussion were VERY helpful. The brass cap broke off my SS unit on extraction. I made 3/4 wide steel “screw driver” from flat stock to remove cap…. worked well. Made custom extraction tool from rod stock and nail using drill press, bench grinder, hydraulic press, and Dremel tool (fortunately had all this stuff!)
    Aug 2017

  7. Jeff

    I had no cold water flow at all; I replaced the spool and now have about 30% flow on the cold side versus 100% on the hot side. Anybody else run into this or have a suggestion? Already changed the cartridge before I found this article.

  8. Gray Lin

    A million thanks for the detail and pictures, to Luke as well. I moved into a house which had been vacant for some time, and this proved to be the issue. I suspect my cartridge was not as fused up as others described above, but here’s what worked for me:
    I did not use a lubricant to unscrew the brass cap, I started by tapping it patiently with a large screwdriver and hammer. The chisel and vice grip technique got it moving.
    Once extracted — it came out as one piece — I used a set of small extraction tools with various hooks and angles to remove the inner spool, working from the openings on the side.
    Following the above advice, I cleaned with a small wire brush and applied silicon lubricant before replacing. Its working fine now…

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