Grundfos Recirculator Pump

[phillipcj]

My house was built in 2004 with a UP-10 B5 Grundfos recirculator pump - it had the timer and aquastat and placed at the return hot water line right before the hot water heater. It ran very quiet. Our house is 3000 sq ft and hot water came pretty quick to all rooms - well under a minute, if not in seconds. Recently our instant hot water at all faucets stopped - it took a few minutes to get hot water going. I looked at our UP-10 B5 Grundfos and it seemed to be making a little bit more noise and was warm. I called the plumber and they told me that the pump was the problem and it would cost $750 to replace. I decided to do it myself and bought the WATTS premier at Home Depot. I installed it and still no instant hot water (actually, only at the kitchen sink which I believe is the closest faucet to the water heater). I placed it in the original spot and also on top of the water heater - did not help any. I figured the WATTS was the wrong kind of pump since it was made to have the sensor valve and I have the hot water return line.

So I decided to buy a little bigger Grundfos pump: UP15-18B5/LC. I just installed it and my hot water situation has not changed. When I had the WATTS installed on the hot water return line right before the water heater, the copper pipes (1/2") before and after the pump were cool. But, with the new UP15-18B5/LC, it's warm before and after, so I'm assuming hot water is being pushed through my hot water lines throughout the house, but still no difference. Here are my questions:

1) Pro Flow water heater safety tank -- I think I read somewhere this is supposed to warm to the touch on the top and cool on the bottom. Mine is cool all the way around. Could this cause problems with my instant hot water?

2) This new Grundfos pump makes more noise too. I bleed the line with the large screw and some air came out. I also ran all the faucets until they stopped sputtering air. Is is typical for the pump to make more noise? The original one was very quiet but I'm thinking this one might different because of the model #.

3) This pump is running very warm too. I'm buying the aquastat for it but not the timer. I don't see a need for both.

Are there other things I should check? I was thinking maybe air lock or something to do with the lines under each sink - each sink has a t connector for the hot and cold lines to connect to (the bathroom sinks). Can these cause problems after awhile?

Any thoughts would be helpful.

Thank you!

Phillip

3)

 

[doitall]

Silly question, but why didn't you replace like for like.

 

[phillipcj]

With the original Grundfos, I had one faucet that had a little more delay on the hot water than other faucets so I figured I would go up one size. I also figured the builder bought the cheaper of the two since they did that on a lot of other items. Also, when the plumber came out to my house to look at my pump he told me my hot water heater was actually almost 10 years old even though my house was build in 2004. So, some items were either refurbished or cheapo items.

 

[tamz]

Sounds more like an air problem to me.
Spend some money on a plumber instead of throwing parts in. Cheaper in the long run and you will have a comeback.

 

[phillipcj]

I ran all the faucets until no air sputtered out so I thought I had that covered. Is there another way to get rid of air. I will call a plumber and have them diagnose it.