Best shower valve for cold water temp fluctuations?

8 years ago

Hi All,

Wasn't sure if this needed to go in the "Bath" forum or if it best here.

We are building a new house and planning to put in a drain water heat recovery system. If you are interested in what this is, you can find info here, but the bottom line is that it takes your incoming cold water temperature (40F-50F) and turns it into much warmer water (70F-75F).

The change in water temperature is not instantaneous, it takes a few minutes for everything to warm up, and the warmup will gradual. With a normal shower valve, this would require constant adjustment. As the cold water coming into the valve gets warmer and warmer, the mix of hot and cold will have to change to maintain a constant temp. It will take less and less hot water as the cold water gets warmer and warmer.

I am looking at the Delta brand. It looks like the 17 and 17T series have technology to maintain the temperature. However, am I correct in believing that the 17 series only maintains temperature by keeping the pressure of both the hot and cold piping the same. If the cold water pressure drops, the valve will drop the pressure on the hot side so the mixture stays the same. However, if the pressure stays the same, but the temperature of the cold water changes, the 17 series valve will do nothing to change the temperature. Do I understand that correctly?

Sounds like a need a 17T series, which is a thermostatic valve?

Sort by:Oldest

Comments (5)

PRO
Cabot & Rowe
8 years ago
Any thermostatic valve should be a good choice. Grohe is excellent in my book
geoffrey_b
8 years ago
Many locales now require a thermostatic valve.

I have Grohe thermostatic valves in my home, and they work quite well.

Not to be negative but that heat recovery system sounds like a real dud. A government boondoggle. I can't believe you would ever get a payback.

Delta Thermostatic / Pressure balanced - explanation
Related Discussions
Cold, cold temps!
Q
Comments (44)
My rooster was getting frostbite regularly until I started rubbing vaseline on his comb and wattles and bought the heat lamp bulb. It's one of those really big red heat lamp bulbs people put in their bathrooms. It's 250 watts and just goes into a regular (but not plastic) socket. It cost me about $10 and has been well worth it. I only run it at night when it's below -15 and the odd day when it is that cold all day. The vaseline helps a lot too. He struggled fiercly until I started stroking his comb with the vaseline. Then he got really still and just stood quietly though the whole procedure. I think he likes it. I've done it a few times. It's necessary anyway, whether he likes it or not. I laughed the first time, as one of the lead hens came up really close, watching, and asking a quiet question. When she got in his face he gave her a little chirp without moving and she went away. I guess she was worried. It was so cute! I remember that about Thunder Bay. The things that do grow well there get HUGE due to the extra long daylight. The blackflies and mosquitoes are fierce but only for a very short period of time, then nothing. They get so bad in May they drive the moose out onto the highways. I saw my only real life bald eagle up north and up close. I actually had to use the break to keep from running into him with the car. He was flying down the highway in front of us. HUGE and gorgeous bird with a wingspan much larger than our car. I had no idea they were so big! I never have the camera when I need it!
...See More
Help! Best temp heating solution for our temp home
Q
Comments (63)
I think you have some good suggestions above regarding heat. Electrical heaters are very expensive. We had two that used dryer like outlets and they cost tons to use. We also went through many of the cheap electric heaters -- they only last so long before they stop functioning. We live in Southern Ontario, Canada. We have been re-building/expanding our house for close to 4 years. We have lived through all sort of horrible, freezing conditions. We have four kids. I have a long winter coat that gets lots of use inside our home. Having a shower is the worst. Don't forget that poly plastic can make a huge difference for pennies to make a wall more insulated. You can poly over tons, and block off a section of your home with poly as well. A few winters ago, we did rent two propane heaters. They were not that great at spreading heat around the home, and they were expensive too. I do hope you find out your old furnace works. I would certainly get a quote to see what that would cost to fix. The difference in fees to rent another heat source, or pay for electrical energy to heat might be more than the furnace repair. Good luck. I hope your winter is not an extreme one. Carol
...See More
Single handle faucet: "Cold water is overriding the hot water"????
Q
Comments (21)
OK, different story after I actually met with the maintenance guy and performed some tests. Here are the facts: 1. Single-level handle for tub/shower with pressure-balanced valve. 2. Tenant does not experience water temperature fluctuations, but supposedly tenants in unit below complain. 3. No water heater in unit, but circulating hot water in building (big boiler). 4. It takes a long time before water actually turns hot when the hot is turned on, both on bathroom sink and tub/shower. Not sure if that's related. 5. So here are the tests: a. Turn hot water on at tub/shower until it's piping hot; turn off; turn HOT on again --- water comes out very cold. b. More interestingly: Turn tab/shower faucet on hot; turn off; then Turn hot water on bathroom SINK faucet --- this is a two handle faucet, so only use hot water handle; water comes out hot, then slowly turns cold; then hot again. c. Now shut off tub/shower valves, so no water gets into the faucet. Do the same thing with the sink faucet as before, i.. e turn on hot; now water will not turn colder but stay hot. So, my question is now: Did the previous plumber incorrectly install the faucet after he took it apart when he fixed a leak, or is the pressure-balancing valve in the tub/shower faucet busted? Either way, I just called a plumber.
...See More
Best shower valve to replace single handle Moen Posi-Temp?
Q
Comments (32)
Hi, There is a shower repair plate you may want to think about. We called them Stainless steel Smitty plates. a skilled plumber can cut a hole in the shower a little smaller than the Smitty plate. He then cuts out the old valve, solder in the new valve ,mount the smitty plate, install the valve trim over the smitty plate. Done. Good Luck Woodbutcher
...See More
cvw_ky
Original Author
8 years ago
last modified: 8 years ago
So definitely a thermostatic valve and not just a pressure balanced valve?

Geoffrey, I believe most locales require pressure balanced valves, not thermostatic.

I appreciate your opinions on the heat recovery system. It might be true that you might not see much payback if you have natural gas, with lower operating costs and quicker hot water recovery. However, I don't have access to NG, so I have to go all electric, which is more expensive and has a much slower recovery time. I was skeptical at first as well. But I have talked to people that have them and they work. And I have read the independent research papers that show they work. And I have calculated the affects on a water heater if you change the incoming water temperature from 50F to 75F. If my calculations are correct, my payback will be instantaneous, because the money I spend on the DWHR system will be saved by being able to purchase a smaller capacity water heater.
geoffrey_b
8 years ago
The pressure balanced only ensure that the hot and cold are mixed evenly.

The thermostatic actually control the water temp to keep it at near the set point.

You have a misunderstanding: "As the cold water coming into the valve gets warmer and warmer, the mix of hot and cold will have to change to maintain a constant temp. It will take less and less hot water as the cold water gets warmer and warmer."

Read the link you posted: the water going into the water heater is being heated - which is the energy savings. The cold water going to the faucet is not being heated - the cold water temp is not going to increase.

Further reading advises you to have a holding tank for drain water - so you can recover more heat. The site claims the payback is 2.5 to 7 years.
cvw_ky
Original Author
8 years ago
Yes, the water goes to the heater, but it also goes to the faucet as well. See the picture posted on the site (my red circle):

As the site states, "some" systems include a storage tank. However, it also says, "Non-storage systems usually have a copper heat exchanger that replaces a vertical section of a main waste drain. As warm water flows down the waste drain, incoming cold water flows through a spiral copper tube wrapped tightly around the copper section of the waste drain. This preheats the incoming cold water that goes to the water heater or a fixture, such as a shower."

We will be doing the non-storage system, and will be running the preheated water to the water heater AND the showers. Running it to both means that the heater doesn't have to work as hard, AND you don't need as much hot water because the cold water isn't as cold.

Best shower valve for cold water temp fluctuations?

Comments (5)

Cabot & Rowe

geoffrey_b

Related Discussions

cvw_ky
Original Author

geoffrey_b

cvw_ky
Original Author

COMPANY

BUSINESS SERVICES

GET HELP

CONNECT WITH US

Best shower valve for cold water temp fluctuations?

Comments (5)

Cabot & Rowe

geoffrey_b

Related Discussions

cvw_kyOriginal Author

geoffrey_b

cvw_kyOriginal Author

COMPANY

BUSINESS SERVICES

GET HELP

CONNECT WITH US

cvw_ky
Original Author

cvw_ky
Original Author