Will a 1/2" male thread to 3/4" PEX affect flow to hot water heater?

[Sbas]

Hi guys. I'm building a tiny house on wheels and my plumber used 3/4" PEX to my hot water heater. This 3/4" PEX goes outside my wall where I will hook up a garden hose to.

the water inlet flanges I am looking at are 3/4" hose thread but the back side is 1/2" male thread.

I would need to use a reducer to connect the 1/2" copper thread to 3/4 PEX.

Just to clarify: 3/4" hose -> 1/2" male thread -> 3/4" PEX.

My question is - will this 1/2" male thread greatly affect the water flow in my 3/4" PEX to my water heater? Would a regulator help?

Thanks!

 

[Reach4]

Is the GHT thread receiving water from the water heater, or is the GHT supplying water to the water heater? I suspect in your case, the GHT is the supply.

In any case, I think an adapter that maintains the ID of 1/2 inch copper or bigger would not have a significant pressure drop. It is not the case that the flow resistance is determined by the smallest path, but rather the flow resistance is the sum of the resistance of the various sections of pipe and hose.

 

[Sponsor]

 

[hj]

Why aren't you using one with a 3/4" male thread?

 

[Sbas]

Hey Reach,

So in other words. I would be fine?

And my water supply will be coming from a garden hose that will feed into my house.

And I made a mistake..looks like the thread is brass. This is the product I am looking at: https://www.amazon.com/JR-Products-...F8&qid=1507172461&sr=8-3&keywords=water+inlet

HJ- Because I cannot find any with 3/4" male thread on the inner side! At least for these rv style flanges (I don't want to use just a regular thread without flange because it is going out a very visible area on my exterior wall.

 

[Reach4]

So in other words. I would be fine?

I think so, but I am not a plumber. For perspective, how large is your water heater?

 

[Sbas]

30 gallon electric water heater. 240v

 

[Jadnashua]

A short restriction doesn't have the same effect as a longer, smaller pipe, but yes, it will make a difference. The area of a 1/2" pipe is about half of the area of a 3/4" one, but 3/4" pex is about the equivalent of 1/2" copper. Because the pex's ID is about the size of the fitting, the pex is the restriction.

It would be better to use a 3/4" one, but the difference, while measurable, may not be very noticeable.