DHW Hot Water Recirculation with Indirect Heater

joodokick

Hi I'm using a boiler for space heating and an indirect hot water heater for DHW, are there any issues with using hot water recirculation with this set up? I can't imagine there would be since the source of the heat for the DHW shouldn't matter, right? Thanks for your time and consideration.

heathead

Some Indirect water heater have a special place for the return line.

Larry Weingarten

Hi @joodokick , Although your indirect should be able to keep up easily with any heat loss from a recirc line, I'd do what's possible to keep the recirc function efficient. I prefer "on demand" pumping as it prevents over 90% of the heat loss from a recirc line. I've dealt with recirc lines that triple the water heating bill. 24 hour pumping can cause erosion damage to any copper piping also. I'd also install valves so you can flush the line or tank individually along with a good, quiet spring check valve.

Yours, Larry

joodokick

heathead said:

Some Indirect water heater have a special place for the return line.

Thanks, I have been having trouble finding one, hence the question.

joodokick

Larry Weingarten said:

Hi @joodokick , Although your indirect should be able to keep up easily with any heat loss from a recirc line, I'd do what's possible to keep the recirc function efficient. I prefer "on demand" pumping as it prevents over 90% of the heat loss from a recirc line. I've dealt with recirc lines that triple the water heating bill. 24 hour pumping can cause erosion damage to any copper piping also. I'd also install valves so you can flush the line or tank individually along with a good, quiet spring check valve.

Yours, Larry

Thank you, we were planning to go with a temperature controlled system, insulated pex lines (all within conditioned space) and all the appurtenances you recommend.