Hot water comes quickly but recirculating pump is off?

[JPTanner24]

Hi,
I had a plumber come and replace my two water heaters. Previous heaters were installed by builder of the home. Fairly straightforward install, did not have to change much.

Once the new heaters were in, my recirculating pump stopped working (taco 006). So plumber came out and replaced the pump (same model).

The pump replacement also was pretty much using the builder's original install, except my plumber added three new things (as can be seen on the left side of the picture below, by the left water heater)

A check valve
A hose bib
An isolation valve (with yellow handle) (to the right of the recirc pump is another isolation valve that you can't see in picture. This was put in by builder)


The strange thing is now:
Even when the new recirculating pump is off (switch to off, unit makes no noise what so ever, not even a slight hum) I still get hot water quickly to all my fixtures. Maybe 5-10 seconds even to the farthest fixture in this two story house. Pretty much no material difference from when the pump is on.

With my old recirc pump, when it was off, I had to wait a long time to get hot water (more than 45-60 seconds).

What's going on? Do I now have some sort of natural circulation going on? If so, why didn't I have it before? Is the check valve doing something? Thanks

Picture of the NEW install:

 

[Jadnashua]

You probably have some natural convective circulation. Without a check valve, unless the pump is on, water will take the path of least resistance, and that may include pulling it from the bottom of the water heater as well as the top. During use, the incoming cold water is directed to the bottom of the tank, and that's where it is typically the coldest. Note, some circulators can be purchased with an internal check valve, and an external one may not be needed.

 

[Sponsor]

 

[rjbphd]

If you are getting hot water at your faucets without the help of the pump, you just wasted money on unneeded pump and check valve,etc..

 

[Gary Swart]

Just last week I had to replace my recirc pump. Yes, I too was getting hot water without the pump, however it took a bit longer and the temperature would not be as hot and would cool off for a few seconds. Much better with the pump.

 

[rjbphd]

If you remove the unnecessary check valve, the water would be hotter and quicker.

 

[WJcandee]

If you are getting hot water at your faucets without the help of the pump, you just wasted money on unneeded pump and check valve,etc..

Well, as said above, it doesn't mean that it is AS fast as with a pump.

If you remove the unnecessary check valve, the water would be hotter and quicker.

Not clear that the check valve is "unnecessary". It may be what has induced the convection.

Both of these were unnecessarily-snarky comments, designed only to make the guy feel bad and you to feel superior. I don't consider either one to be helpful or accurate.

 

[rjbphd]

Feeling superior? Nope, speaking from my experience proves what you don't know.

 

[Terry]

We always install a check valve with a recirc pump. Normally a spring check.

 

[CountryBumkin]

Terry, what brand/model spring check valve are you using. Is it brass?
I am getting ready to do my recirculation system. I have the pump, and a brass "swing" check valve. Should I be using a spring check valve?

 

[rjbphd]

How many check valve or pump you see on gravity hydronic heating system?

 

[Gary Swart]

This attack apparently aimed at me doesn't bother me. I have had my recirculating system in place for about 8 years. I installed it exactly as the Laing installation sheet specified and it worked 100% perfectly running 24/7 (no timer) When the pump finally quit, the water water would start fairly warm, the cool some, then get hot. Convection, I know. I could have lived with this, but I wanted to get back to virtual instant hot water so I bought a new Laing pump and replace the old one. Now it works like it used to and I am pleased. I am not accustomed to disregarding a manufacturers installation instructions and assuming I will know better, but I do try to pay attention to the professionals on this forum that offer their opinions on things. For example, when setting a new toilet, I now know not to follow the wax ring instruction to place the ring on the toilet and then set the toilet onto the flange. No, the ring goes on the flange first then the toilet sets on top of that. But, in most cases the manufacturer knows their product better than I, so I listen to them.

 

[Jadnashua]

If you don't have a check valve, when you draw water, you'll get water from both the top and the bottom of the WH...the exact mix will depend on the lengths of the individual runs and how they are run (number of fittings, how much slope, etc.). When the WH is full of hot water, it doesn't' really matter...when things start to get depleted, it can make a huge difference as the water at the top will still be hot while that at the bottom can be frigid.

 

[WJcandee]

This attack apparently aimed at me doesn't bother me.

I thought he was aiming at the original poster...

 

[hj]

A gravity hydronic system is NOT a recirculation system, so it does NOT need a pump or check valves. A recirulation system DOES NEED a check valve.

 

[rjbphd]

A gravity hydronic system is NOT a recirculation system, so it does NOT need a pump or check valves. A recirulation system DOES NEED a check valve.

Show how much you don't know about the system.. If it not a recirculation system.. then how does it works?