I have a recirculation pump attached above the water heater. It is set to turn on for about 6 hours/day intermittantly during peak usage times.

When it is on, the cold water in the kitchen and upstairs bathroom (which is directly above the kitchen) is very hot. It stays hot no matter how long I leave the water on. If I turn the recirculation pump off, this problem goes away. Also, the upstairs bathroom toilet fills with hot water too when the pump is on. Other parts of the house are not affected.

When the recirculation pump is off, the upstairs bathroom shower has no hot water pressure. The cold water has normal water pressure but the hot only has a trickle. With the recirculation pump on, the hot water pressure is normal but of course I get scalding hot water from both the cold and hot.

I have had the setup for 4 years without a problem until a few months ago. No new plumbing work has been done.

Is there a simple fix or should I call the plumber?

What brand and model number recirculation pump you got, Thanks.

John

Hello Erebay,

If the sensor fails will give this problem, Thanks.

John

Thanks for the quick reply!

It's a Grundfos

Type: UP 15-10 B5/TLC


So I may need a new recirc pump?

Do you have a check valve in the cold water line above the recirculation pump?

Thanks for the quick reply!

Its a Grundfos

Type: UP 15-10 B5/TLC


So I may need a new recirc pump?



We tried that same system and didn't like the fact that the comfort valves stay open anytime the system is off or water in the hot water line isn't hot. Getting cold water was a pain because the open valve kept letting water from the hot water pipes bleed into our cold line until the valves finally closed from water hot enough to close it. It sounds to me that your valve has failed. A number of people have had the same problem only they were taking a shower when they suddenly received scolding hot water out the shower head no matter how they adjusted the cold and hot knobs. We decided we didn't want to worry about our kids getting scolded nor did we want to wait for cold water all the time so we returned it and got a Redytemp. We've had it for 5 years now and love it.

No I don't think you will need a new pump, the problem will be with the sensor or the comfort valve failure which is a common problem with the recirculating pumps, see the images below it may be similar to yours pump I don't have a trouble shooting page for this type but I do have it for the Watts pump which works the same you can open that and go to page 5 will tell how to check the valve (Sensor) let us know when you do this test, if you don't have do this type then I will suggest to contact they will tell you how to test this, I wouldn't bit on it but am sure that this is not the pump it is the sensor or the valve, Good luck.

John

Thank you all!

I tested the sensor valve by closing off the cold water supply to the valve and sure enough hot water continually flowed from the cold side.

I am going to buy a sensor valve on Ebay. I couldn't find one at Home Depot.

I will let you know how it goes after the replacement.

Again, thanks to all for the help.

Nice going John ! Wanted to rate your answer but system would not allow me to...

1DIYMOM: Sorry about your negative experiences with Groundfo products. The Groudfo circulation pumps are great pumps, relatively inexpensive and will give you many years of service. They sell all over the world. We have been installing them for many years with great success. The failure of the sensor has really not too much to do with the pump itself.

Thanks Milo for considering to rate me and yes I a gree with you about Grundfos products it works great I have experience with both Grundfos and Watts, 1 years ago I had problems with Watts not the pump but sensor, Replaced the sensor no problem sense.

Regards,
John

Thanks everyone.

I received the sensor valve last week and installed it. Very easy install - less than 5 minutes. The water inside the valve was very dirty and black. Maybe it was clogged?

My problems are fixed with the brand new valve!

Hello Erebay,

Appreciated that you kept us in the loop and am glad that we could help, Thanks.

Regards,
John

Good to hear you were able to fix your problem with John's help !