Connecting existing Pex A to Pex B to add circulating pump.

[moresun]

Hello,

I'm adding a circulating pump to a dedicated loop line that is Pex A. I don't have the expansion tool so would like to use steel rings since I have the tool for that. My question, since Pex B fittings are smaller in diameter, will the flow restriction be noticeable? Thank you.

 

[John Gayewski]

The flow restriction will only be in your recirc line how would you notice that?

If your using a hot button or some other control there could be a noticeable delay in the hot water arriving but it might be a secondo or two. As long as your using 3/4"pipe you should be fine.

 

[Sponsor]

 

[moresun]

Thank you for the reply.

I'm adding a check valve to the on the cold water inlet and will be using the Pex A to Pex B which is my concern.

 

[John Gayewski]

Thank you for the reply.

I'm adding a check valve to the on the cold water inlet and will be using the Pex A to Pex B which is my concern.

Is this a tankless heater?

 

[moresun]

No. 50G Tank

 

[John Gayewski]

Then you'd be better off configuring it with the pump on the return line pumping back to the heater (into a tee on the drain) with a check valve between the heater and the pump.

 

[moresun]

Then you'd be better off configuring it with the pump on the return line pumping back to the heater (into a tee on the drain) with a check valve between the heater and the pump.

Why is the drain better than the inlet?

 

[John Gayewski]

Your not sharing use. Each pipe has its own purpose. Plus you don't have to use your tiny fittings on your supply piping.

 

[moresun]

Your not sharing use. Each pipe has its own purpose. Plus you don't have to use your tiny fittings on your supply piping.

Haha. tiny fittings indeed. It makes sense but curious, does the manufacturer approves such a method? Voids warranty?

 

[Tuttles Revenge]

Haha. tiny fittings indeed. It makes sense but curious, does the manufacturer approves such a method? Voids warranty?

we always install the return to the supply piping. I don't like having it down in the drain, especially mounting the pump down near the drain, its a bunch of piping that has to be removed to replace the tank.... but whatever method works. It may actually help with keeping sediment more dispersed.

The only manufacture I found with a recirculating diagram was Bradford White and they simply show it piped to the return, but don't mention Not being able to replace the drain valve. Drain valves are threaded and intended to be replacable, so I can't see it being a warranty issue.

 

[Jeff H Young]

when you pipe a recirc system the only portion thats conceidered a return line is that section after the last fixture, so if you (picked up a fixture on the way back to water heater) that isnt a return line but a supply line untill it leaves that last tee. Im not sure how much a single barb or 2 , would slow down the circulation obviously the size of the main supply and return makes a differance as bigger pipe requires moving a larger amount of water as well , Ive seen 1/2 and 3/4 work well on medium size homes in copper

 

[John Gayewski]

Haha. tiny fittings indeed. It makes sense but curious, does the manufacturer approves such a method? Voids warranty?

The manufacturer doesn't care. The I ejection method is better for tankless heaters. Tanks get it in the drain. The pump can go where is convenient. A swing check should be horizontal though.

 

[moresun]

when you pipe a recirc system the only portion thats conceidered a return line is that section after the last fixture, so if you (picked up a fixture on the way back to water heater) that isnt a return line but a supply line untill it leaves that last tee. Im not sure how much a single barb or 2 , would slow down the circulation obviously the size of the main supply and return makes a differance as bigger pipe requires moving a larger amount of water as well , Ive seen 1/2 and 3/4 work well on medium size homes in copper

the return line is a 3/4.

 

[moresun]

The manufacturer doesn't care. The I ejection method is better for tankless heaters. Tanks get it in the drain. The pump can go where is convenient. A swing check should be horizontal though.

Check me please.

 

[John Gayewski]

View attachment 91953
Check me please.

From the water heater (on the bottom) it should go nip, valve, then tee. That let's you fill the return line with water and purge the air from the drain.

 

[John Gayewski]

Also use a ball valve boiler drain. That should screw directly into your tee.

 

[moresun]

From the water heater (on the bottom) it should go nip, valve, then tee. That let's you fill the return line with water and purge the air from the drain.

The check valve? Nip, check valve, tee, boiler drain?

 

[John Gayewski]

The check valve? Nip, check valve, tee, boiler drain?

No just a ball valve. You have a valve drawn after the check valve. That valve should be between the tank and the tee. You'll thank me later when you go to try to remove the air from the return line.

 

[moresun]

Got it. The pump has an internal check valve, should i still install the spring loaded check valve or is that an over kill/cause issues? Also, is this the boiler drain HERE?

 

[John Gayewski]

Got it. The pump has an internal check valve, should i still install the spring loaded check valve or is that an over kill/cause issues? Also, is this the boiler drain HERE?

That is not a ball valve style boiler drain. That's a multiturn valve. Quarter turn=Ball valve.

Preferably your pump would not have an internal check valve but since it does you should probably just use that. In my experience you should be prepared and on the lookout for that internal check valve to fail and need changed out.