Replace faucette valve - American Standard Plumbing

Hi and welcome to FixYa, I am Kelly.

What is happening is that your cold water flow is greater in volume (gals per min) than your hot water. So when you open the cold water it is mixing with the hot water inside the faucett or shower plumbing and actually reverse flowing back into the hot water heater plumbing. The reverse flow slows the water flow sensing turbine inside the heater and it is thinking that there is not any water flow. (There isn't actually due to the equalization of water pressure when you open the cold water faucett) Since this is a safety feature of the tankless heater to keep it from overheating, it shuts off.
Somewhere in the hot water plumbing there is a major restriction. It may very well be the internal plumbing of the tankless hot water heater or the flow detector design.

There are 2 ways to correct this. The easy way would be to restrict the available cold water flow. You can do this by installing another shut off valve inline with the cold water plumbing and just not open the valve all the way. You would have to adjust the setting so that the hot and cold water can be on at the same time and the hot water heater stays on. The hard way is to locate the hot water flow restriction and eliminate it.
It is possible.... if you have a flow restrictor in a shower head or a screen in a faucett areator that they are partially clogged. Clean any flow restrictors and screens then see how the hot water heater performs before you start modifying plumbing.

Thanks for choosing FixYa,
Kelly

An F20 code is telling you that the anticpated fill time limit has been exceeded.

This can be caused by
1. Dirty water inlet screens on the water valve. Also possibly the hoses at the wall connection if the unit was installed with additional hose screens.
2. Kinked water supply hoses
3. LOW WATER pressure
4. A weak or open coil of the inlet water valve solenoid.
5. A kinked or restriction of the hose that goes from the water valve to the tub inlet.
6. (VERY RARE) A defective machine control board.
7. Bad faucett washers on the wall connection hose bibb where the rubber faucett washer has deterorated and is blocking or restricting water flow inside the shut off valve on the wall.
8. Debris blocking the diaphram of the water passages inside the inlet water valve (Can not be verified by disassembly due to the construction of the water valve.) You must check flow rate into the tub after verifying all the possibilites above except #6.

These are all real possibilites and each one of them must be checked out. This is not a difficult task and a good many washing machine users should be able to isolate the problem.

If you need machine specific information we will need your make and model number to assist you in the future.

Thanks for choosing FixYa.

Kelly

Open the cover plate up at the faucett and replace the faucetts cartrage and rubbers, sound like somting in that region has parished
Hope that is the problem

This is a common problem with this valve. Try placing the valve in near boiling water then set to cool before trying again. It worked for me until the next time it failed and I got a different system.

That's where a mechanic has a feel for things and just looks for any set screws or threads, a handyman might help with this for you.

Go to home Depot or loew and buy the seat replacement kit for your model of faucett. Your going to have to break out the tools (Philipps Screwdriver and a larger adjustable wrench) The remove the shower knob cover with a knife to access the mounting screw. Remove the screw and then the knob. (STOP!) Go turn off the water for the residence now! Then come back and remove the nut holding the faucett in place. The whole assy will with a little effort will come straigth out at you. Moen isnotorious for having to remove a plate from the bottom of the valve. NOTE the position of that plate and then remove it. Remove all of the seat seals one at a time and replace them with the new ones you purchased. Reinstall the NEW lower plate in the same position you removed the old one. Reinsert the assy back into the valve body. Tighten the retaining nut. Reinstall knob and secure with screw. Replace knob cover. Turn on the water NOW. Enjoy the non-leaking faucett.

You can get a repair kit to replace the insides of most single hanle valves. turn the water off, remove the handle, some have a screw on top or one in the side. Then remove the large nut and the insides will come out.

There can be particulate inthe water valve assy that is keeping the diaphram of the soleniod from shutting off the water supply completely. You can try this and it sometimes works. Trun off and disconnect one hose from the faucett / hose bibb and select warm on your machine. Place the loose hose into a bucket and let the water flow into the bucket until it is about 25 % full. Reconnect the house you just used to back flush the water valve with to the faucett / hose bibb.. Then turn off the water for the other hose and repeat the back flushing into the bucke until it gains another 25 % of content. Turn off your machine reconnect the hose and then turn on the water. Then see if the water filling when not in use continues. This works most of the time. There are exceptions when the particulate is to large to clear that is stuck in the water valve. I am assumjing that this happens even if the unit is unplugged. Give it a try and good luck.

Replace cartridge and insure that the C clip is not missing.

Depends if you have a single handle faucet or double or spray attachment