# Recirq lines



## redbeardplumber (Dec 4, 2012)

I see this ALL the time. Whether it has a pump or if it's gravity fed. How do you get the air out of the recirq line with no valve between tank and sediment faucet. It makes me crazy!


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## rjbphd (Feb 5, 2010)

redbeardplumber said:


> I see this ALL the time. Whether it has a pump or if it's gravity fed. How do you get the air out of the recirq line with no valve between tank and sediment faucet. It makes me crazy!


 If its piped in correctly by a hockey fantic plumber at the far faucet, you won't have that problem.


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## HSI (Jun 3, 2011)

No check valve with a bleed?


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## redbeardplumber (Dec 4, 2012)

Let's assume the pic has no pump. How do you get the air out? This Hockey fan puts a ball valve at bottom of tank then a sediment faucet upstream on recirq. Close valve and then we can get all the air out, otherwise your just pushing tank water out sediment.


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## RealLivePlumber (Jun 22, 2008)

I hear ya. 

Every single one I see doesn't have a way to purge the air. 

I guess the homeowner doesn't notice the delay, and the installer figures that the pump will push the air out:no:

And of course the installer don't care..............


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## rjbphd (Feb 5, 2010)

RealLivePlumber said:


> I hear ya.
> 
> Every single one I see doesn't have a way to purge the air.
> 
> ...


I do care.. pipe it correctly without pump and its will purge itself.. have to be a hydronic heating guy to understand.


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## Michaelcookplum (May 1, 2011)

Where's the swing check?


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## rjbphd (Feb 5, 2010)

Michaelcookplum said:


> Where's the swing check?


Don't need it if its piped correctly.


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## jmc12185 (Aug 27, 2013)

If it's a gravity line you don't need a swing check. If there's a pump than you do need a swing check. If the pump broke than cold water would be coming out the hot side without a check valve

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## rjbphd (Feb 5, 2010)

jmc12185 said:


> If it's a gravity line you don't need a swing check. If there's a pump than you do need a swing check. If the pump broke than cold water would be coming out the hot side without a check valve
> 
> Sent from my iPhone using PlumbingZone


Nope... what differeance done it make?? If the pump failed, then it would becomes a gravity system. 
And if the system works with the failed pump, then you don't need a pump !


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## MTDUNN (Oct 9, 2011)

redbeardplumber said:


> I see this ALL the time. Whether it has a pump or if it's gravity fed. How do you get the air out of the recirq line with no valve between tank and sediment faucet. It makes me crazy!


When you say sediment faucet, do you mean the petcock?


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## jmc12185 (Aug 27, 2013)

rjbphd said:


> Nope... what differeance done it make?? If the pump failed, then it would becomes a gravity system. And if the system works with the failed pump, then you don't need a pump !


 the difference is that you can't use gravity systems in every house. They just won't work in some applications depending on the layout of the house. Systems with a pump can be used anywhere, doesn't matter where the water heater is. In which case, you need a check valve.

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## jmc12185 (Aug 27, 2013)

Installing a pump with a swing check and an aquastat is definitely the better way to go in my opinion.

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## wyrickmech (Mar 16, 2013)

jmc12185 said:


> If it's a gravity line you don't need a swing check. If there's a pump than you do need a swing check. If the pump broke than cold water would be coming out the hot side without a check valve Sent from my iPhone using PlumbingZone


a recirculating loop has to have two check valves one is on the cold water feed to the water heater,the other is at the pump. The first check is there to keep HOT water from migrating back in the cold water. The second check keeps the water from back feeding and spinning the pump backwards. There is not a instance where you would get cold water from the reticulating line it is all on the hot side.


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## redbeardplumber (Dec 4, 2012)

MTDUNN said:


> When you say sediment faucet, do you mean the petcock?


Yes


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## redbeardplumber (Dec 4, 2012)

rjbphd said:


> I do care.. pipe it correctly without pump and its will purge itself.. have to be a hydronic heating guy to understand.


I pipe my homes with gravity recirq lines and I understand how they work. Are you saying the cooler water will push the air out of that line into tank?


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## jmc12185 (Aug 27, 2013)

wyrickmech said:


> a recirculating loop has to have two check valves one is on the cold water feed to the water heater,the other is at the pump. The first check is there to keep HOT water from migrating back in the cold water. The second check keeps the water from back feeding and spinning the pump backwards. There is not a instance where you would get cold water from the reticulating line it is all on the hot side.


 you are 100% wrong.... If there was no check valve and the pump burned out, they will get cold water out of the hot side of the faucet since the cold feeds to the bottom of the water heater and the recirc ties into the hot water line. I've seen it a million times.

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## jmc12185 (Aug 27, 2013)

If there's no check valve and a burned out pump what's going to stop the cold water from the bottom of the tank from pulling up to where the recirc line ties in when the hot water is being used ??

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## jmc12185 (Aug 27, 2013)

And if the pump is on, how the hell is the wAter going to back feed and spin the pump backwards? The pump is actually pulling the wAter from the hot water lines. There is no draw the other direction.

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## MTDUNN (Oct 9, 2011)

redbeardplumber said:


> Yes


 ok then I agree with you. Air trap sucks. But engineered properly within code requires more $$ in the quote


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## wyrickmech (Mar 16, 2013)

jmc12185 said:


> you are 100% wrong.... If there was no check valve and the pump burned out, they will get cold water out of the hot side of the faucet since the cold feeds to the bottom of the water heater and the recirc ties into the hot water line. I've seen it a million times. Sent from my iPhone using PlumbingZone


one I said it requires checks two on a pumped recirculating line the hot would be where the water would flow from because of sizing. The hot is sized for demand the recirculating line is smaller and does not need to move water more than 5 feet per min. So the restriction on the recirculating line would be greater. Water takes the path of least resistance. If it is drawing out of the recirculating line I would say something is sized wrong


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## wyrickmech (Mar 16, 2013)

jmc12185 said:


> And if the pump is on, how the hell is the wAter going to back feed and spin the pump backwards? The pump is actually pulling the wAter from the hot water lines. There is no draw the other direction. Sent from my iPhone using


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## jmc12185 (Aug 27, 2013)

wyrickmech said:


> one I said it requires checks two on a pumped recirculating line the hot would be where the water would flow from because of sizing. The hot is sized for demand the recirculating line is smaller and does not need to move water more than 5 feet per min. So the restriction on the recirculating line would be greater. Water takes the path of least resistance. If it is drawing out of the recirculating line I would say something is sized wrong


 yes, I understand that and agree. The only problem I had with what you said is that the cold water will never mix into the hot side which is untrue.

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## jmc12185 (Aug 27, 2013)

It may not come out freezing cold but you'll never get full hot because it's pulling from both lines at once.

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## wyrickmech (Mar 16, 2013)

jmc12185 said:


> yes, I understand that and agree. The only problem I had with what you said is that the cold water will never mix into the hot side which is untrue. Sent from my iPhone using PlumbingZone


it won't if you put a check vale on it which you need anyway. If it fails you fix. We never used the drain for the recirculating line anyway it was always the inlet to the tank. Always had two checks never had any problems. The recirculating line was no more than half the size of the hot so it would not draw out of it. Also a thermal loop was required about half of the time


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## jmc12185 (Aug 27, 2013)

Yes, that is why I always put check valves. Everyone does things differently and everyone has preferences. The bottom line is that it works properly, that's most important.

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## redbeardplumber (Dec 4, 2012)

Excuse my ignorance. "thermal loop"?


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## rjbphd (Feb 5, 2010)

jmc12185 said:


> And if the pump is on, how the hell is the wAter going to back feed and spin the pump backwards? The pump is actually pulling the wAter from the hot water lines. There is no draw the other direction.
> 
> Sent from my iPhone using PlumbingZone


And when the pump (usually way oversized) is running, the check valve is totally useless.


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## rjbphd (Feb 5, 2010)

redbeardplumber said:


> Excuse my ignorance. "thermal loop"?


 If ya drop the down at least 24" and back up.. the thermal flow will stop in the pipe..


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## redbeardplumber (Dec 4, 2012)

And when would you use a thermal loop? Obviously not with a gravity system. So it prevents the drawing of cooler water back thru recirq...??


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## rjbphd (Feb 5, 2010)

redbeardplumber said:


> And when would you use a thermal loop? Obviously not with a gravity system. So it prevents the drawing of cooler water back thru recirq...??


Right... can be used on cold water line before going to heater.. on some jobs, I have dropped the supply to near the floor and back up to ceiling before dropping into heater.


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## redbeardplumber (Dec 4, 2012)

^^^^ why did you need to do this RJ. New install or a problem.


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## MTDUNN (Oct 9, 2011)

rjbphd said:


> Right... can be used on cold water line before going to heater.. on some jobs, I have dropped the supply to near the floor and back up to ceiling before dropping into heater.


you can also thermal loop both hot and cold on top of the unit


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## redbeardplumber (Dec 4, 2012)

These thermal mostly commercial applications ?


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## rjbphd (Feb 5, 2010)

redbeardplumber said:


> ^^^^ why did you need to do this RJ. New install or a problem.


 When the water heater is too close to water treatment unit(s), you don't want hot water thermal back into them.. check valve will stop the flow but not the thermal temps..


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## redbeardplumber (Dec 4, 2012)

Ahhh. Great point thanks RJ!


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## rjbphd (Feb 5, 2010)

redbeardplumber said:


> Ahhh. Great point thanks RJ!


Ur welcome..now back to hockey..Flames sucks


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