Pipe sizing

Brad White_52

3/4 inch would be plenty if not oversized if it is a 'not so big house'. 3/4" is in my experience more germaine to a commercial building.

The only function of the recirculation line is to drag hot water near your most remote fixtures so that you do not have to purge the line of cold water each time. (You probably know this of course.) Only a trickle is needed, less than half a GPM, the principle being to move enough water to keep ahead of the pipe heat losses. So insulate the lines thoroughly.

As a general rule and not that you asked, I mount the circulator or at least the thermostat near the remote fixtures, not back at the heater. That way you are only responding to the fixture needs not heating the return line all the time it is on.

To your cross-connection question, Weezbo is right, check valves may be a need. Another thought is, what if the system were set up originally using the CW line as the return line? If such is the case, your engineer's fix may be designed to rectify that, by giving a return path of its own.

JoeC

Pipe sizing the recirc

I'm at a total mental loss in regards to sizing piping systems, where a recirc line system is installed. I'm forgetting alot with age. My engineer has specified a 3/4" recirc line, the last three fixtures are 1/2" supplies equipped with mixing valves. I'm battling a cold into hot cross connection now, on all three fixtures. If I close down on the recirc line, it's not so bad. Any Help Here?

Alan(OnVacationInOregon)Forbes

Come again?

Are we talking heating or DHW?

JoeC

Domestic hot water Alan

I pray that I'll still get some response. Sorry to bother you, some of us still have to wear a hat or two. Any input?

Weezbo

sounds like a check or three would Heal the ordeal

just a thought.

JoeC

thanks for all your input. I spent time last night looking into some thermostatic mixing valves that have internal checks. And I've loaded up a box of gauges and fittings to install today to try and determine where and why I'm getting such a pressure differential at the remote fixtures.More to come.....

Techman

pipe size-recirc line

Hi guys. Just a question on using the cold water line as the recirc line .Would the customer experience a problem with the cold water tap being too hot, from the temp of the recirc water? Thank you.

Brad White_52

Yes.