# Hot water recirc



## stecar (Mar 18, 2012)

Have customer that wants to install a recirc pump on heater. No recirc line is there now. House is approx 4,000 sq ft. I have spoke to a few guys and they said watts makes a kit. Pump on heater and some sensor on farthest fixture. 
Anyone have any experience with this?


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## OldSchool (Jan 30, 2010)

stecar said:


> Have customer that wants to install a recirc pump on heater. No recirc line is there now. House is approx 4,000 sq ft. I have spoke to a few guys and they said watts makes a kit. Pump on heater and some sensor on farthest fixture.
> Anyone have any experience with this?


You can use an aquastat to control the temp on the return ... This way it will turn off and on .. On it's own 

Or you can put a timer on it ...

Both would be installed close to the tank ..


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## stecar (Mar 18, 2012)

If its close to tank, will it work properly? I would imagine near the tank would be warmer than opp side of the home.


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## rjbphd (Feb 5, 2010)

OldSchool said:


> You can use an aquastat to control the temp on the return ... This way it will turn off and on .. On it's own
> 
> Or you can put a timer on it ...
> 
> Both would be installed close to the tank ..


 How would that work if there's no re circ line??? 
I've stated many times that if you install the recirc line properly, you won't need a pump.


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## OldSchool (Jan 30, 2010)

rjbphd said:


> How would that work if there's no re circ line???
> I've stated many times that if you install the recirc line properly, you won't need a pump.


Of coarse you need a return line silly ...

Just saying the controls and pump can be at the tank


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## BigDave (Mar 24, 2012)

This is the one I like and have had the best results from...

http://www.armstrongpumps.com/present.asp?groupid=0&market_sectionID=01&classID=05&modelID=009

I like the adjustable mixing valve and the timer on the pump.
Make sure you have power near the tank for the pump or make
it the customer's concern.

You get one mixing valve in the box with the pump and you could buy
extra mixing valves ( the pump will run three of them ) if needed.


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## OldSchool (Jan 30, 2010)

rjbphd said:


> How would that work if there's no re circ line???
> I've stated many times that if you install the recirc line properly, you won't need a pump.


It would work with out a pump as long as it didn't go up and down creating a heat trap...

The other alternative is leave the hot tap running... Lol


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## GREENPLUM (Jul 27, 2008)




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## rjbphd (Feb 5, 2010)

Is this one of the one people will complain of too luke warm water from the cold side?..


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## stecar (Mar 18, 2012)

Green is that the watts?


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## BigDave (Mar 24, 2012)

stecar said:


> Green is that the watts?


Grunfos


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## BigDave (Mar 24, 2012)

rjbphd said:


> Is this one of the one people will complain of too luke warm water from the cold side?..


The luke warm water only lasts for a few seconds, it's the price you pay
for the convenience.


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## JK949 (Mar 18, 2009)

rjbphd said:


> Is this one of the one people will complain of too luke warm water from the cold side?..


Yep, you need to explain to interested customers that it's either this or running a new line.

An add on system will flow water back through the cold pipe to the heater so they get to choose what is more important. Also, hard water can clog up the sensor, a vinegar soak can clear things up overnight.

Get your PEX tool ready.


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## UN1TED-WE-PLUMB (Oct 3, 2012)

rjbphd said:


> Is this one of the one people will complain of too luke warm water from the cold side?..


Just let it run for a min... It will get cold 

Customers usually aren't very fond of this.


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## OldSchool (Jan 30, 2010)

What ever you don't use upnor pex on the return it is not approved for return water


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## rjbphd (Feb 5, 2010)

UN1TED-WE-PLUMB said:


> Just let it run for a min... It will get cold
> 
> Customers usually aren't very fond of this.


 That's just the same as running the hot water for a few minutes to get hot...


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## rjbphd (Feb 5, 2010)

OldSchool said:


> What ever you don't use upnor pex on the return it is not approved for return water


 Huh??? Why??? Its not as hot as the hot supply...


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## OldSchool (Jan 30, 2010)

rjbphd said:


> Huh??? Why??? Its not as hot as the hot supply...


Upnor (wirsbo) issued a notice a few years back saying that their pex fails prematurely with continous flow on return lines do to the chlorine content in the water


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## JK949 (Mar 18, 2009)

OldSchool said:


> Upnor (wirsbo) issued a notice a few years back saying that their pex fails prematurely with continous flow on return lines do to the chlorine content in the water


Copper will fail too under the same conditions. Timers with aquastats on circ systems.


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## rjbphd (Feb 5, 2010)

OldSchool said:


> Upnor (wirsbo) issued a notice a few years back saying that their pex fails prematurely with continous flow on return lines do to the chlorine content in the water


 But what about the flow in the cold and hot pipes??? Something fishy here...


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## JK949 (Mar 18, 2009)

Any pipe under constant flow will fail prematurely. We see pinhole on copper recirc lines all the time where the pump is constantly running. Now it is very common to find pumps with timers built in on the shelf, add an aquastat for more protection.


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## rjbphd (Feb 5, 2010)

JK949 said:


> Any pipe under constant flow will fail prematurely. We see pinhole on copper recirc lines all the time where the pump is constantly running. Now it is very common to find pumps with timers built in on the shelf, add an aquastat for more protection.


 Oh bs.. main reason copper fails on return line is the pump is way oversized for the job to being with...


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## OldSchool (Jan 30, 2010)

rjbphd said:


> But what about the flow in the cold and hot pipes??? Something fishy here...


I few years back I went to wirsbo/upnor training and sales 3 day event and that was one thing they brought up ... They will not warranty their pex on a hot water return line ... Reasoning the continous flow of chlorinated water breaks down the pex ...

I just tried to google it ... But I am going to have to dig a bit...


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## OldSchool (Jan 30, 2010)

Hmmm ... Trying to find it ... It seems like they are now allowing it ...
If you know a sales rep for wirsbo/upnor you should ask them ...


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## GREENPLUM (Jul 27, 2008)

rjbphd said:


> Is this one of the one people will complain of too luke warm water from the cold side?..


 
Its the only way to have hot water quickly without installin a return line and pump.


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## victoryplbaz (May 19, 2012)

If they dont or cant run a return line for the pump at the water heater. Then your stuck using one of the units that use the cold water for the return. If you use the grundfos you can use the timer.


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## rjbphd (Feb 5, 2010)

OldSchool said:


> I few years back I went to wirsbo/upnor training and sales 3 day event and that was one thing they brought up ... They will not warranty their pex on a hot water return line ... Reasoning the continous flow of chlorinated water breaks down the pex ...
> 
> I just tried to google it ... But I am going to have to dig a bit...


 Thanks, I will read it for sure.


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## HSI (Jun 3, 2011)

Grunfos system has a timer and gets the job done. If they use the timer correctly to cover the few hours a day that makes sense it works well. If they choose to let it run continually it may cause issues with hot water on the cold side.


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## phishfood (Nov 18, 2012)

I have never installed one, but I have heard of systems that return to the cold line like others mentioned here, but have a motion sensor that turns on the pump when someone walks into the bathroom. 

Anyone have any experience with such a system?


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## antiCon (Jun 15, 2012)

GREENPLUM said:


>


 ive installed one of these (customer supplied).. the down side is when you turn on a cold tap you can get hot water out of it and then since your pulling cold water back into the cold line (where you have Hot water in as well ) you get a "cold water sandwich effect" such as on some of the tankless units with high flow rates ... week or so later the HO had me take it out :no:


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## GREENPLUM (Jul 27, 2008)

phishfood said:


> I have never installed one, but I have heard of systems that return to the cold line like others mentioned here, but have a motion sensor that turns on the pump when someone walks into the bathroom.
> 
> Anyone have any experience with such a system?


Ive seen the motion sensor on the Taco On'Dmand for tankless


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## JK949 (Mar 18, 2009)

rjbphd said:


> Oh bs.. main reason copper fails on return line is the pump is way oversized for the job to being with...


Do what you want, I'm selling filtration systems.:thumbup:


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## rjbphd (Feb 5, 2010)

JK949 said:


> Do what you want, I'm selling filtration systems.:thumbup:


 Did you become a liensced plumber or still apprentice??


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## JK949 (Mar 18, 2009)

rjbphd said:


> Did you become a liensced plumber or still apprentice??


Just checked my profile, never updated it. I got my j-card in 2009, posted a thread about it, and planning to take contractor's test next year.


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## rjbphd (Feb 5, 2010)

JK949 said:


> Just checked my profile, never updated it. I got my j-card in 2009, posted a thread about it, and planning to take contractor's test next year.


 Great! Good luck on the test!


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## JK949 (Mar 18, 2009)

rjbphd said:


> Great! Good luck on the test!


Thank you! I've been unsure for a while, then I had a supervisor pull me aside and tell me that he thought I would be shortchanging myself if I never went for it.


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## love2surf927 (Dec 22, 2011)

OldSchool said:


> I few years back I went to wirsbo/upnor training and sales 3 day event and that was one thing they brought up ... They will not warranty their pex on a hot water return line ... Reasoning the continous flow of chlorinated water breaks down the pex ...
> 
> I just tried to google it ... But I am going to have to dig a bit...


I had a conversation with a fellow contractor today regarding the chlorine on pex recirc lines. If the issue was the chlorine would it not react the same with the piping while it's at rest in the pipe as well. Am I missing something?


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## rjbphd (Feb 5, 2010)

love2surf927 said:


> I had a conversation with a fellow contractor today regarding the chlorine on pex recirc lines. If the issue was the chlorine would it not react the same with the piping while it's at rest in the pipe as well. Am I missing something?


Full of it... why the chlorine would be different on the supply, hot water and return with slightly lowered temps? Its the freaky over velocity of the flow that's hurting the any kind of pipe!


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## love2surf927 (Dec 22, 2011)

rjbphd said:


> Full of it... why the chlorine would be different on the supply, hot water and return with slightly lowered temps? Its the freaky over velocity of the flow that's hurting the any kind of pipe!


Yes this is what makes sense to me as well.


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## mightypipe (Dec 22, 2012)

phishfood said:


> I have never installed one, but I have heard of systems that return to the cold line like others mentioned here, but have a motion sensor that turns on the pump when someone walks into the bathroom.
> 
> Anyone have any experience with such a system?


In my experience, it takes about15 mins to make the loop, so this wouldn't work well. I have customers that have wireless remotes. They turn on pump about 1/2 hr before use.


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## Cal (Jun 17, 2008)

I use the same grundfos system on my eternal water heaters and folks have been very happy . 
Yes they do mention the luke warm water at the cold side . However , once they are convinced to NOT have the pump running all day ,, things are much better ! 

Some things they WILL have to live with . I AM NOT THE INTERNET ! YOU can NOT HAVE EVERYTHING YOU WANT AT THE PUSH OF A BOTTON !!!


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