Question about Water Heaters

1 Answer

Excess Hit Water Bill from Solar/electric Hot Water System

Recirculation pump runs 24hrs a day to 4 levels. Does this pump allow the free flow of hot water when turned off? Ours appears not to as we then only get Luke warm water. The recirculation appears to constantly cool the hot water and we therefore need 240volts all the time. our quarterly Hot Water usage is 4000 kw - 2 people careful with usage. No swimming pool. Can you help?

Posted by on


1 Answer

  • Level 3:

    An expert who has achieved level 3 by getting 1000 points


    An expert that got 20 achievements.


    An expert that got 10 achievements.


    An expert that got 5 achievements.

  • Water Heaters Master
  • 5,245 Answers

Cost calculations for recirculation system vary widely.
These systems cost more, and they cause higher operation cost of water heater.

1) When pump is OFF, then hot water is no longer leaving the tank.
Most recirculation systems have choice of timer for setting specific times of operation, or thermostatic operation that activates pump when sensor detects temperature less than 90 degrees

2) Condition of plumbing is suspect here because you are not receiving fully 90 degree hot water from the recirculation system.?.

Bad single-handle faucet cartridge, or bad recirculation check valve, are causes of crossover. Clean recirculation check valve with white vinegar. Replace worn faucet cartridge.
Test for crossover.

3) There are other suspects, such as water leak.
Drips, broken pipe, bad TP valve.
Turn off all taps and put ear against pipe to listen for running water.

4) High costs: Lifting single-handle faucet in middle will immediately cause cold water to enter tank. Even if no hot arrives at tap, because the cartridge is drawing both hot and cold in equal amounts when handle is lifted in middle.
Today it is more efficient to install dual-handle faucets so tank is not receiving constant dose of cold water when single-handle faucet is not used correctly or tediously.

Posted on Oct 30, 2012


6 Suggested Answers

  • 2 Answers

SOURCE: I have freestanding Series 8 dishwasher. Lately during the filling cycle water hammer is occurring. How can this be resolved

A 6ya expert can help you resolve that issue over the phone in a minute or two.
Best thing about this new service is that you are never placed on hold and get to talk to real repairmen in the US.
The service is completely free and covers almost anything you can think of (from cars to computers, handyman, and even drones).
click here to download the app (for users in the US for now) and get all the help you need.
Good luck!

Posted on Jan 02, 2017

  • 7 Answers

SOURCE: boiler overheating

the problem there a relay stuck or thermostat bring on the pump & you can lower your high limit aquastat!! also the flow valves can bypass hot hot water risers time to put in a seperate water heater domestic coil are not energy efficient !!!! aquastat high limit set @ 180f deg low limit set @ 140f deg!!!
good luck!!! tim

Posted on Oct 18, 2008

  • 6674 Answers

SOURCE: extreme hot water then to consistent luke warm

Possible thermostat problem. Are you experienced enough in that area to do some testing. Have a multimeter? If not experienced, don't try it, too dangerous. Call in a service person.

Posted on Mar 07, 2010

  • 14 Answers

SOURCE: Problem with valves in Grundfos hot water recirculation system.

Yes, you need to replace it.

Posted on Sep 30, 2010

  • 2510 Answers


The WH 40 is a double throw switch, meaning that it will switch two contacts simultaneously. If you are switching the pool pumps with this WH 40 they will all switch at the same time without the desired delay. (You do not mention how the pumps are switched).
To connect the timer for the elements, a live and a neutral are needed to run the clock.
A live is connected to the two switched 'in' terminals and two wires must then be run to each of the coils on each of the two relays.. A separate live must go to each pole of each relay, the switched live then goes through the thermostats and to the elements.
A neutral must also go straight to the neutral side of each relay coil and to each element, unless you are using double pole relays, in which case you can switch both the neutral and the live wires going to the relays (this is the preferred circuit). Then each switched live will go to a thermostat and the switched neutral will go the other terminal of the heater element. The elements you are using are very heavy and your relays will have to be able to handle around 120 amps at 110 volts or about 60 amps at 220 volts. At 220 volts your 40 amp contactors will only handle 8.8 kw with no safety margin.
If you want a safety feature to time the pumps and elements separately, you will either need two timers or perhaps a pressure switch or flow switch to isolate the heaters when the pump pressure or flow falls.
Come back to me if this layout does not agree with what you have in mind or I have not made any point clear enough.

Posted on Apr 01, 2011

SOURCE: I have a gas Rheem

Sounds like you have cold water entering the hot pipe, or crossover.

(A) Put bucket under water heater overflow pipe, and stand back from scalding water. Gently open and close the TP relief valve on water heater. Check temperature of water to see if heater genuinely has hot water.
It could be the water heater has sediment build-up and is no longer able to heat the water, or the gas thermostat is bad.

(B) If water heater has hot water, and hot is not getting to faucet, then you have a crossover problem somewhere.
1) This problem can be located at crossover point of a recirculation system, if re-circ check valve has failed.

2) Failure of a single handle faucet cartridge can cause crossover.
Read how to test for crossover:

3) Other causes for crossover are a failed check valve elsewhere in the plumbing system, for example on the pool equipment. Also a failed mixing valve which is usually installed on top of the water heater so that some areas of the house like laundry room receive very hot water, while the kids bathroom receives lower temperature water.

Upvote the help.
And take advantage of fixya expert assistance live.
For a price, expert works with you while you work on water heater or any do-it-yourself project.
Fixya is always less expensive than a service call.

Posted on May 16, 2011

Add Your Answer

Uploading: 0%


Complete. Click "Add" to insert your video. Add



Related Questions:

1 Answer

Solar hot water not hot

Solar hot water giving you cold showers? Eight tips to warm you up.
Eight tips to get the most from solar hot water
We argue that policy needs to look beyond installation and that installation practices need improving, but what can you do to get an effective installation?
First, seek out independent advice from sources such as local sustainability events and organisations. They can help you understand what suits your circumstances and what characterises an effective installation.
A good organisation is theAlternative Technology Association. They provide free advice to members, sell a solar hot water guide, and organise open house events where you can see and discuss domestic sustainability technologies.
Second, consider whether solar hot water is the best option. It may be that a hot water heat pump or an instant gas system is a suitable choice, depending on where you live, how much cloud cover you have, or what sort of building you are in.
Third, make sure all your hot water pipes are insulated, especially the pipes that go to and from the tank and solar panels. You typically need insulation to be 15 mm thick. Without proper insulation you could lose half the energy you are trying to collect.
Fourth, get a booster switch installed in a convenient place inside, so you can easily turn the booster off if there is plenty of sun, or on if it's cloudy or you need more hot water.
Fifth, if you go solar, install a system that has a sufficiently large tank matched with a sufficiently large solar array for your needs. Water is very good at storing heat. A large tank could help you store solar energy for those rainy days.
Sixth, you may need to change electricity tariffs if your booster is electric, to ensure the sun gets a chance to heat the water before the electricity does.
Seventh, you may need to change your peak hot water use habits so that the tank water is at its coldest after morning use, after which the sun can then heat it during the day. The booster can "top up" overnight, ready for morning showers.
Eighth, before you install solar hot water, examine and discuss household expectations around hot water use. Will they need to change? Are members of your household prepared to make that change?
This may be the most profound change you can make, but also perhaps the most challenging.

Oct 30, 2016 | Water Water Heaters

1 Answer

Cold water side will not get cold

we are loss to understand this question
with hot water systems the water in is at normal temperature ( day /night ) and it is heated either by solar to electric/ gas to make the water hot
the hot water system will not make water colder only hotter.

Apr 09, 2015 | Water Water Heaters

1 Answer

I have a Navien NR 240A tankless which has been in use for about a year. My only complaint is that when the internal recirculation pump turns on I can hear a waterflow or pump noise throughout the house...

Hi Bruce
No its not normal it shud b isolated by lagging the noise travels through the timber lagging between pipes will help also how old is the pump shud only b a hum if pump ok any more and u need to replace , also u mite like to check speed of pump mite b on max turn down so long ur flow is ok or ur system mite get to hot

Sep 17, 2013 | Water Heaters

1 Answer

I have an 80 gallon Rheem Hot water heater #81V80D A. In the last 5 days it stopped heating water after 6PM. I have hot water all day, but none at night. What do you suggest?

1) I bet the water heater has hot water, but hot does not arrive at tap because of bad faucet cartridge or bad recirculation system check valve

2) When cold water arrives at tap, go check if water heater has hot water. Then do the crossover test. Then add comment and say what you discover

3) Electric water heaters can be repaired by homeowner using generic off-the-shelf parts from local hardware store.

Feb 18, 2013 | Rheem Water Heaters

1 Answer

Cold water runs good; hot water diminished flow then shuts off completely.

Question posted under autocirc recirculating system.
Unknown if system has been taken apart and cleaned with white vinegar, or if faucets are single-handled.
Open following links to help isolate possible problems.

Oct 08, 2011 | Laing Thermotech Autocirc Undersink...

1 Answer

I have a laing cirulating pump thats is worhing but now making noise so i took it apart see nothing but it was hot when running so is there any thing i can do to fix before it burns out

Open following link for Re-circulation information and resources:

If the unit is getting hot, it may have already slowed and is now spiraling to it end.
Try bleeding air out of water lines, and clean autocirc with CLR calcium lime and rust remover.
Recirculation systems have a built in check valve so cold water side of faucet will work correctly. If this check valve is stuck open or closed, it can affect a lot of things in the plumbing system.
For example, stuck check valve can cause tankless water heater not to operate. It can also cause autocirc pump to overheat.
Lines, or elbows clogged with sediment can also cause same problems with recirculation system. If your system has direct return line to water heater that connects into the water heater drain port, then clog in line can cause overheated pump. Check water flow, check water lines, and clean out autocirc.

Upvote the help.
And take advantage of fixya expert assistance live.
For a price, expert works with you while you work on autocirc or any do-it-yourself project.
Fixya is always less expensive than a service call.

Oct 22, 2010 | Laing Thermotech Autocirc Undersink...

2 Answers

Problem is i have a gravity fed system and yesterday connected a cold water line for an evaporative cooler to the cold water line coming of it. now there isnt any hot water

water will always find its own level and take the path of least resistance. if your hot water tank inlet is higher than the swamp cooler this may be your problem. you can try a line resrtiction at the cooler or a twelve volt rv pump with a battery and solar charger and an on off switch.know someone with this set up and it seems to work well.

Nov 28, 2009 | Water Heaters

Not finding what you are looking for?
Water Heaters Logo

Related Topics:

91 people viewed this question

Ask a Question

Usually answered in minutes!

Top Water Heaters Experts

Brad Brown

Level 3 Expert

16987 Answers

Paul Carew

Level 3 Expert

3238 Answers

Gil Shultz

Level 3 Expert

3382 Answers

Are you a Water Heater Expert? Answer questions, earn points and help others

Answer questions

Manuals & User Guides