I have a gas water heater with a circulation pump (for far areas of my house). Lately, when turning on the cold water in my master bath -- which is about 110 feet from the water heater, hence the circulation pump -- the water is hot until it has a chance to run through. This takes about 3-4 minutes and is a tremendous waste of water.

At first, this problem just appeared in the areas farthest away from the heater, but lately, it has been showing up in the kitchen, which is about 30 feet from the heater.

Before I call the plumber who installed the system, does anyone have any suggestions? I see from previous postings that such a problem may be caused by a "check valve", whatever that is.

Thank you in advance.

If the Sensor Valves fails or installed wrong you will have hot water on the cold side for a few seconds or a few minutes.

To trouble shoot the sensors:
1. Close the cold water angle valve below the sink.
2. Open the cold water faucet.
3. Water should slowly flow from the faucet until hot water reaches the valve.
The flow should gradually decrease until no water is coming from the faucet.
4. If the water flow doesn't stop it means that the Sensors are failed and needs to be replaced.

If the Sensor Valves fails or installed wrong you will have hot water on the cold side for a few seconds or a few minutes.

To trouble shoot the sensors:
1. Close the cold water angle valve below the sink.
2. Open the cold water faucet.
3. Water should slowly flow from the faucet until hot water reaches the valve.
The flow should gradually decrease until no water is coming from the faucet.
4. If the water flow doesn’t stop it means that the Sensors are failed and needs to be replaced.

Thanks! I tried tried your troubleshooting instructions. The sensors have failed. I'll call the installation team who put it in three years ago.

Again, thanks for your "right-on" directions!

What brand is your Recirulating Pump (system)? Thanks.

John

Circulating pump is a Grundfos. The hot water heater is a Bradford White Defender system. There is also a Therm-X-Span safety tank attached.

Is the sensor replacement something I can do, or will it need a plumber?

JPG

Hello JPG

Yes you can if you can find it where it is installed normally they are installed under the far most sink and the are very easy to replace them, see the picture below, God Luck.

John

Yes, sensor may be defective...

But also, remember, it is the way this Instant-Hot water system operate. There always will be some warm water notable in cold water side at your sink. The warm water is being pushed by the pump into cold water side at your sink until adequately hot water arrives. Then it shuts off. When water cools down to 96 degrees F - it starts pushing hot water into cold, again... This means, you will always have warm water in cold water pipe.

Hello Milo Happy 4th of July to you and All,

I agree with you but not for long time as JPG stated and also he did the test and he confirmed that the Sensor is defective, Thanks.

Regards,
John

Hello JPG

Yes you can if you can find it where it is installed normally they are installed under the far most sink and the are very easy to replace them, see the picture below, God Luck.

John

John, thanks. Yes, mine are under the sink. Where do I go to find them? Does Home Depot or Lowe's, or do I need to go to a plumbing supply?

Thanks,

John

Yes, sensor may be defective...

But also, remember, it is the way this Instant-Hot water system operate. There always will be some warm water notable in cold water side at your sink. The warm water is being pushed by the pump into cold water side at your sink until adequately hot water arrives. Then it shuts off. When water cools down to 96 degrees F - it starts pushing hot water into cold, again... This means, you will always have warm water in cold water pipe.

Thanks, Milo, for the admonition. The cold water stays hot for sometimes up to 5 minutes. I can run it through a bit more quickly if I turn on the bathtub or shower cold faucet and let it run; but as stated earlier, that's a big waste of water.

I'm going to try to replace the sensors and see if that fixes the problem.

John

Hi John,

I think Home Depot or Lowe's may have it, you take the model number with you and they be able to help you, I am attaching the pump and the instruction link how to install the sensor, Thanks.

John

http://www.freshwatersystems.com/specifications/L-UP-TL-043.pdf

Hi John,

I think Home Depot or Lowe's may have it, you take the model number with you and they be able to help you, I am attaching the pump and the instruction link how to install the sensor, Thanks.

John

http://www.freshwatersystems.com/specifications/L-UP-TL-043.pdf

John,

Your diagnosis was absolutely correct. I learned that the sensor valves are only available from a Grundfos distributor, so I called my original plumber who did the installation. He confirmed your diagnosis, and mentioned that in recent weeks he's had three such sensor valves go south, which he thought to be strange. Anyway, he's ordered me a new one.

Thanks so much for your help in this matter.

John G.

Hi John,

Thanks for the update, please let us know when you get it it fixed.

Regards,
John

Hi John,

Thanks for the update, please let us know when you get it it fixed.

Regards,
John

John,

Just an update to the hot water in the cold water faucet problem here in Oregon: Ordered the sensor valve from the plumbing contractor who installed the system; he delivered it, and I installed it. Everything works perfectly now.

Thanks for your help.

John

Hello John,

Thanks for the update, and it is my pleasure that we could help.

Best regards,
John