evox45
Member
Yeah, I have the blue one in the photo above.
Hot Water Recirculation
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So, when the pump is off and therefore not circulating water, doesn't it have a relatively good amount of pressure drop across it with the water flowing through the pump housing and turning the unpowered impeller?
Wouldn't the installation of the pump on the hot water outlet side of the water heater be required to run whenever you have a hot water demand instead of just filling the hot water supply line with hot water?
In any case, as the purpose of this particular pump is to warm the hot water line and fill it with hot water just prior to using hot water and then be turned off, wouldn't the best place to install the pump on this recirculating system that has a dedicated return line be taking suction from the return line and pumping into the bottom of the water heater?
You’re welcome. Glad you found the problem.
It took a little over 2 seconds longer to fill a 5 gallon bucket flowing through the pump. Pump was not running for either test.
That’s about 10 gpm.
I think that’s plenty
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Nice test, but that does not replicate the conditions of the installation.View attachment 41911View attachment 41912View attachment 41913View attachment 41914
It took a little over 2 seconds longer to fill a 5 gallon bucket flowing through the pump. Pump was not running for either test.
That’s about 10 gpm.
Your test is using the entire pressure available, what 50 psi? The question is, "What is the pressure drop across a pump that is not running and a flow rate of 1-3 gpm." And "Does that pressure drop cause inconsistent flow issues in the delivery of hot water to fixtures?"
The pump doesn’t restrict flow enough for you to notice.
Refer to my bucket test above.
The pump is made to be used in conjunction with the bypass valve but it’s not mandatory you use the bypass if you have a return line.
I’ve used these pumps both ways and they’ve worked every time.
The pump is designed to screw directly into the hot piping system, even directly to the water heater as described in the instruction manual.
The pump is also built to leave running 24/7 or be placed on intermittent operation. It works either way.
When a pump is running it doesn’t need a check valve on the return. When the pump is off it does need a check valve on the return as you’ve discovered.
If you have anymore questions just ask and I’ll be happy to help.
As the test Twowaxhack used is based on a pressure drop across the pump of 50 psi or so, that test does not show that flow through a pump that is off in a hot water supply line to fixtures will not be a problem. Flowing 10 gpm with 50 psi motive force is one thing, but will 1-3 gpm be able to turn the impeller on a non-powered pump without causing a drop in pressure that will impact the flow of hot water to the fixtures.
And should the pump bearings fail, which does happen, the pressure drop would be even more as the flow will not be able to turn the impeller. With the pump taking suction from the return line, a failed pump will have NO impact on delivery of hit water to the fixtures.
Something like the following.
And should the pump bearings fail, which does happen, the pressure drop would be even more as the flow will not be able to turn the impeller. With the pump taking suction from the return line, a failed pump will have NO impact on delivery of hit water to the fixtures.
Something like the following.
The pump is built by the manufacturer to be installed on the outlet of the water heater and to run 24/7 or intermittent.
Enough said.
Enough said.
evox45
Member
this is great thanks. I was wondering if there was any flow restrictions but it doesn't look to be anything noticeable. Thanks for dropping a lot of knowledge on me. Appreciate all the time you took.View attachment 41911View attachment 41912View attachment 41913View attachment 41914
It took a little over 2 seconds longer to fill a 5 gallon bucket flowing through the pump. Pump was not running for either test.
That’s about 10 gpm.
Ludington
Well-Known Member
I wonder what that does to the dynamics of the water heater, with a constant mixing of the tank.
And if the pump isn't running 24/7 how does it get turned on... by a timer of some sort?
And if the pump isn't running 24/7 how does it get turned on... by a timer of some sort?
If the circ pump runs then it causes the water to lose heat as it circulates and it’ll make the water heater burner/element run more to recover.
You can use timers, aquastats, motion detectors or manually turn the pump on. Some pumps come on when flow is detected.
I ran more tests. 2 gallons a minute at 50psi with the pump and without. With that flow rate there was virtually no difference in time to fill the bucket or pressure drop that I could measure.
I also jammed the impeller with a piece of wire coat hanger. No change at 2gpm flow rate.
I also jammed the impeller with a piece of wire coat hanger. No change at 2gpm flow rate.
evox45
Member
I used a smart plug on mine and it can be activated by voice as well. It's scheduled to run in the morning every 30 mins for 3 mins for around 2 hours. Now that I've got my check valve issue fixed it's working really well. Before this it took me almost a minute to get hot water upstairs so I assume I'm saving some money on water.
evox45
Member
This is really good to know. At first I thought there was a flow issue and the volume of cold water was a lot greater than that of the hot.
You were 100% correct because you had a check valve that wasn’t closing.
Cold Water was coming down the dip tube of the water heater and flowing backwards through the return. You will get some hot/warm water but not much under those circumstances.
Your test is still not legitimate. You are using the entire 50 psi available across the stopped pump. You need to add pipe, a manifold, more pipe, and a shower head after the stopped pump and see the impact to the flow at the shower head. Each of those items need to have pressure as a motive force for the water to flow.
You’re incorrect.
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I checked flow at 80 psi,65 psi, 50 psi and 40 psi. During flow and static.
The flow rates at lower pressure were basically the same.
I had a hose valve creating back pressure on the pump and a pressure gauge.
I jammed the impeller.
Basically no measurable change.
All that PLUS the manufacturer allowing it to be installed in the flow while the pump is running and when it’s not running…….tells me that I have a person who is attempting to make a convoluted wreck of a thread for nothing.
The OP has been helped and we found a check valve that wasn’t closing. Problem solved.
Adding restrictions such as piping, manifolds is useless. Everyone’s house is different and we’re just checking the loss through the pump not an entire plumbing system.
Plus everyone who has this pump says their flow has not been affected.
The flow rates at lower pressure were basically the same.
I had a hose valve creating back pressure on the pump and a pressure gauge.
I jammed the impeller.
Basically no measurable change.
All that PLUS the manufacturer allowing it to be installed in the flow while the pump is running and when it’s not running…….tells me that I have a person who is attempting to make a convoluted wreck of a thread for nothing.
The OP has been helped and we found a check valve that wasn’t closing. Problem solved.
Adding restrictions such as piping, manifolds is useless. Everyone’s house is different and we’re just checking the loss through the pump not an entire plumbing system.
Plus everyone who has this pump says their flow has not been affected.
I think I’m going to find something better to to with my time.
evox45
Member
Yep, I haven't heard any complaints from the wife so I'm assuming we're all good now,I've got hot water everywhere and temps are stable.I checked flow at 80 psi,65 psi, 50 psi and 40 psi. During flow and static.
The flow rates at lower pressure were basically the same.
I had a hose valve creating back pressure on the pump and a pressure gauge.
I jammed the impeller.
Basically no measurable change.
All that PLUS the manufacturer allowing it to be installed in the flow while the pump is running and when it’s not running…….tells me that I have a person who is attempting to make a convoluted wreck of a thread for nothing.
The OP has been helped and we found a check valve that wasn’t closing. Problem solved.
Adding restrictions such as piping, manifolds is useless. Everyone’s house is different and we’re just checking the loss through the pump not an entire plumbing system.
Plus everyone who has this pump says their flow has not been affected.
