no hot water flow at shower


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Old 10-10-08, 02:17 PM
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no hot water flow at shower

i could really use some advice on this before i start ripping walls apart. the hot water at my shower is only coming out as a trickle. the cold water is fine. however, the hot water works properly at the sink in the same bathroom, as well as at every other outlet in the house.
i have a moen single lever faucet so i took out the cartridge and replaced it. didn't help. hot water is still not flowing. i took the cartridge back out and ran the water for about 10 seconds to see if i could blow out any sort of blockage. didn't seem to help. is there any way i can try to snake the copper pipe to see if there is indeed a blockage somewhere? any other suggestions to try? i really don't want to start dismantling walls and pipes to rectify this. thanks.
 
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Old 10-10-08, 05:06 PM
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Do yo have galvanized pipes in an old house?

Do you have the Moen Positemp? (the kind where you just turn the lever up to 270 degrees, without having to pull out the knob first?

With the cartridge not in there, is the cold water pressure real forceful? Can it send water clear to the back wall of the tub 5 feet back?

IF the cold pressure is fairly paltry also, perhaps it is affecting the metering pin in the cartridge that balances the temp.

Since it is the hot water not really working, how do you know how little HOT water is coming out, since the cold water will always be flowing with an open cartridge? Have you actually felt(or used thermometer) the cold water and determined it is not any bit more warm than what your cold water feels say at the bathrom sink? Be sure of this so we really know if you do not get hot water there at the mixer.
 
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Old 10-10-08, 05:20 PM
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Originally Posted by ecman51`
Do yo have galvanized pipes in an old house?

Do you have the Moen Positemp? (the kind where you just turn the lever up to 270 degrees, without having to pull out the knob first?

With the cartridge not in there, is the cold water pressure real forceful? Can it send water clear to the back wall of the tub 5 feet back?

IF the cold pressure is fairly paltry also, perhaps it is affecting the metering pin in the cartridge that balances the temp.

Since it is the hot water not really working, how do you know how little HOT water is coming out, since the cold water will always be flowing with an open cartridge? Have you actually felt(or used thermometer) the cold water and determined it is not any bit more warm than what your cold water feels say at the bathrom sink? Be sure of this so we really know if you do not get hot water there at the mixer.
copper pipes, not galvanized.

not the moen positemp. not sure what it's called, but it's where you pull the knob straight out from the wall, and then up to 90 degrees left or right for temp. control.

with the cartridge removed, the cold water did indeed shoot all the way to the back of the tub. very forceful.

i know how little hot water is flowing because it's the same amount with two different cartridges in the faucet. very little water. i actually had a shower with it like that, but had to pretty much max out the lever to the full hot position in order to get the mixed water warm enough to shower by. unfortunately, this resulted in the water pressure being so low that i wasn't able to rinse the shampoo out of my hair.

when the hot water is flowing (which is very little) it is very hot. just not enough flow to make a difference.

does that help?
 
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Old 10-10-08, 06:52 PM
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So just to be sure, when this water shoots across the tub, does the water feel quite warm or barely warm? What I am trying to determine, since you have copper pipes, if say a solder pellet got lodged in the mixer, or if a huge wad of water heater dip tube broke loose, or if say the bottom of your cartridge came off and is still in the base of the mixer. But if the latter was the case, I'm thinking you maybe would not be able to lock back in the new one. Make sure when you look at the bottom of each cartridge that the same stuff is there on each.

If it is the mixer we have to come up with a plan to force water from cold through the hot under pressure. The trouble, is, by using your own water, you also unfortunately energize the cold water. If you had a cold water shut off for the tub, it be simple. Do you by chance?

Otherwise we have to get more creative in being able to flush water through just the hot ports. And water blasting is better than air blasting, as air can compress more around obstructions.

If you had a close neighbor, you could shut off your house water and tie into his house water, and tie the garden hose into your water heater drain and close off the cold water valve on the water heater and open the water heater drain and open the neighbors spigot and his water pressure would go up your water heater (and not come out the cold side as that valve is closed) and then see what comes out the mixer, and to what amount. Or you can tie his garden hose into your hot laundry spigot, and also make sure the cold valve on the water heater is shut off. Then one can also use backflushing techniques.

Another way of being creative is if you knew how to sweat solder and have all the stuff, you could cut the right line say in the basement? and be able to use your own house water to pull this flushing and backflushing business off.

But DO you have a big high volume air compressor?, as that is an option worth trying, perhaps, first, with the water shut off. Then if you shut off the hot water heater's cold valve to prevent back blasting through the water heater and having it come out the cold side - you then also have to open a hot water valve elsewhere in the house somewhere so the air you are blasting with has a place for it and water to get pushed out.
 
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Old 10-10-08, 07:54 PM
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wow, that all sounds pretty crazy. when the water was shooting to the back of the tub, it wasn't warm. you'd only want to shower in something that temp if you'd just met angelina jolie.
both cartridges looked the same.
no water shut off of the tub. sorry.
i took the cartridge back out and tried to poke a coat hanger just inside the hot water pipe. after a little work with that, i started to see a little copper oxidation (had the greenish colour of oxidized copper) coming out. turned on the water to flush it out. got a little trace of oxidation in the tub. this has helped the flow somewhat. getting a little more now. hopefully enough to shower by for now.

as for the suggestions of blowing the water through the hot water heater, i may have a partial solution. it just so happens that right now they're doing water main work on my street and my regular water supply is shut down. all of our water in the house is being supplied through a garden-like hose through our outside tap and backfed into the house. would that provide the water pressure you're referring to? if i was to shut off the cold tap on the water heater, would that have the same effect?

unfortunately, the air conditioning unit was obviously installed afterwards as the point where the hot water line branches off to go upstairs is above a mess of ducting. not easy to get at. obviously the previous owner tried as the joist is charred there too. that would be a last resort i think.

i do have an air compressor. where would i be injecting the air? into the cut pipe? or somewhere else?

i really appreciate your brainstorming on this for me. cheers.
 
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Old 10-11-08, 09:58 AM
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I have another idea. The objective is you need to BACKFLUSH the hot line. Forward flushing is what the shower is already trying to do, and since you have something hung up in the line, this will not help. So we need to backflush.

To do that, we can use your cold water this way:

Turn off your house water.

Put your cartridge back in and turn it to the WARM position.

Shut off the water heater's cold valve above your water heater.

Open up at least one other hot faucet in the house.

Make sure all cold water faucets are off and toilets have not been flushed.

Remove your tub spout and shower head and cap off those two lines.

Now you are ready! When you turn the water on, this is what will happen:

Water will enter the house, and reach the water heater and cannot push out hot water. At the same time, cold water will enter your mixer valve because it is set on warm. The water will not be able to come OUT the spout pipe nor shower pipe because you capped them off. This means it will try to push water thru the hot side of the mixer! With the other hot faucets open in the house, in theory, the water may (let's hope!) try to push backwards through the mixer and DOWN the hot pipe towards other open hot faucets. It will not be able to pass through the water heater because you turned off that valve above it. It has to try, at least, to force the hot water thru your mixer and out some other hot faucet!

When you are doing this, go out by the main house valve and QUICKLY turn the water cyclically on and off, as these pulsations help send a surge of PSI through the pipe in a hammering effect. I do this all the time when clearing rust scale out of pipes.

Disregard my previous posting as I should have thought of this idea last night.

In the meantime, I am going to call up my master plumber friend and see if he ever heard of a spring steel type flexible cable, similar to what doctors use to do angioplasty on heart blood vessels, to see if something is available to bend and send through mixer valve port holes and back into the piping. The only thing I can think of close to my thought process would be garage door cable. I have lots of that laying around and have never tried that. I'll quickly post back what he says if he answers his phone. Besides, I have to call him anyway as he is setting me aside 3 things I need to buy from him.

.........................................................................

I just called him up. He has never himself ran into your problem, and he is over 50 (but younger than me). He said he has gotten stuff out by leaving out the cartridge. But I told him that I too have run into the posters problem and forward flushing does not always work. That you have to backflush. He thought my solder pellet theory was plausible.

You could also adapt my water theories to air copmpressor and back blast. I do not feel like making an entire new lsit on how to do that again, and I think you can figure out what you would have to do based on the things I posted above. But if you need help in this regard, I guess I will try to help. This one post here alone took me an eternity. I could have been out making $20 bucks. :biggrin:
 
 

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