[Loulicious]

Hello everyone, new guy here. First time forum poster long time forum reader.

I have an issue with my cold water over powering my hot water. This is the case at all faucets and tubs in my home. I can turn the hot water on all the way, which has decent pressure and very hot water. But as soon as I barley turn the cold water on the temp drops very quickly. And if I turn the cold on more than half way I have nothing but cold water. As if the hot is not even on. I have an 8 year old electric dual element hot water tank; which is maintained regularly. This has been an issue since we purchased the home a year before installing this tank. I have also replced two of the faucets since replacing the water tank and have the same results. So as not to create an issue of not posting enough info, here is a list of what I have. Please ask for any other info that you may need to help assist with the issue.

30 gallon electric dual element water tank (no circulation pump)
Installed directly under kitchen/bathroom with 5 to 8 feet of pipe to all fixtures
1/2 inch PVC plumbing throughout entire home
(next project is to increase to 3/4 inch for main supply run thoughout home; decreasing to 1/2 inch for supply lines to fixtures)
1/2 hp shallow well jet pump (cut in/out 40/60psi)
Water filter for entire home(changed monthly)

I appreciate any info you all can provide for me. Let me know if any other info is required.

 

[TheEplumber]

Tell us about your sink faucets and tub/shower faucets. You may have a bad cartridge

 

[joecaption]

Sure hope it's CPVC not PVC.
Changing the incoming and outgoing main run for that water heater to 3/4" will about double the available flow

 

[Loulicious]

TheEplumber: Tub faucet is a moen single knob faucet. (came with the house). Bathroom sink is a moen single knob faucet (2 years old). Kitchen moen with seperate hot and cold knobs( less than 1 year old). And sorry, but I don't know what a cartridge is.

joecaption: Yes all the plumbing is CPVC.

 

[TheEplumber]

If the problem existed before the heater change out, I suggest you contact Moen for a replacement shower cartridge.
I believe you're passing cold water through the valve. This is a known characteristic of Moen.
They should honor their lifetime warranty

 

[Loulicious]

I will get in touch with moen and see what they can do for me. But as I stated above; the issue affects all faucets in the house, not just the shower. The two sink faucets had the problem before and after I replaced them.

 

[Loulicious]

joecaption mentioned that increasing the pipe diameter to 3/4 inch to and from the tank could double the flow. Which makes sense to me. Larger pipe, larger volume of water that can pass through the pipe with less restriction. But if everything is 1/2 inch now; and I increase everything to 3/4, won't the system be exactly how it is now, just with a higher flow of water, both hot and cold? Or should I only increase the pipe diameter from the well pump to the tank, then keep the cold water at half inch to all the faucets. And only drop the hot water to 1/2 at the individual supply line under the sinks and at the tub. Creating a higher flow of hot water while keeping the cold water restricted to not over power the hot.

 

[AllanJ]

Try this.

Turn on only the hot full blast at one sink or fixture. Now turn on the cold water moderately at a different fixture. Does the hot water stream get much weaker?

There may still be some constriction in the hot water line. Are some of the hot water pipes old notably steel or galvanized steel? They can develop arteriosclerosis over the decades. Does your water heater have heat traps in the connection nipples up top? The latter sometimes get sluggish and restrict the water flow. No ill effect is caused by substituting ordinary nipples for heat traps.

 

[Loulicious]

AllanJ: I tried what you suggested. And I didn't see any significant decrease in hot water pressure or temperature. All of my plumbing is CPVC, so no corroded pipes. As far as the heat trap thing goes I am not sure if I have them or not. I googled "heat trap" and found a picture of what i think i remember seeing on the tank. I haven't seen that part of the tank since install(8 years ago). And unfortunately when the tank was installed; unions were not used in the installation. So i will not know for sure until i do my plumbing retrofit. But being the connection to the tank is CPVC to the stainless nipple on the tank it shouldn't be clogged due to corrosion. Although I won't know until it take it apart.

 

[Bondo]

Ayuh,.... Maybe it's just me, but it sounds more like a technique, rather than a plumbin' problem,...

I've always turned the Hot on to get decent flow, let it hot, 'n then add just enough cold to adjust the temp,.....

I can shower for days that way,....

If I turn on the Hot, full blast, 'n Cold full blast, it gets cold, 'n I run outa hotwater in no time, gettin' Really cold,....

 

[ben's plumbing]

after reading all the comments here...I have to assume it sounds like a cross over problem... because the one test you did..the hot water did not decrease as you opened the cold.....a side note....I would not install a 30 gal electric water heater for standard home....it is just not big enough..imo..

 

[AllanJ]

Another thing to try:
Turn off the washing machine faucet set.
Turn off all other fixtures using the individual faucets, not at the end of a sprayer hose.
Crossover can occur at these locations if the faucets are not closed.

(The washing machine faucet set should be turned off when you are done using the machine. Flooding due to burst hoses ranks way up there in terms of insurance claims.)

 

[SHEPLMBR]

definitely a crossover problem. Start with your single handle cartridges