Linking two tankless heaters double minimum flow?

johnaxJune 5, 2011

The major tankless water heater manufacturers advertise that you can connect two identical units in parallel to double available capacity. Does that cause the minimum flow necessary to start (and sustain) the heater(s) to double (i.e. half the water always goes through each heater) or does the system keep a valve in the "slave" heater closed until it's needed, so at first all the flow is through the "master"?

Thank you for reporting this comment. Undo
zl700

If you purchase compatible units and use thier communication cord or package, they will link together and operate in sync with sequential firing. Yes one will close the inlet valve so that minimum flow to activate one heater is not affected.

    Bookmark   June 6, 2011 at 9:15AM
Thank you for reporting this comment. Undo
lazypup

Generally in a residential application where you would have enough demand to require two separate tankless you would most likely also have some rather long runs of pipe from the source to the demand. Rather than try to place two units in tandem at one locaton I would be more inclined to divide the loads into two zones and place separate units to handle each zone. That would decrease radiational losses from long pipe runs, help provide a more balanced supply to the demands and would definitely eliminate the need for expensive complex lead/lag control systems.

    Bookmark   June 7, 2011 at 3:13AM
Sign Up to comment
More Discussions
Marble shower panels valve replacement :( !!!
We have a couple of bathrooms with a single handle...
Vamsi Kodavanty
Hot water backflowing into cold supply
OK, I'm rephrasing my question, as what I'd asked before...
pjb999
Terminox ISM for iron/manganese removal
Hi, I have had a water softener with other assorted...
merlin2552
Improving water pressure to outside spigot
I would like to improve the pressure and flow rate...
greasetrap
Salt-free water conditioning
Hi all, Considering installing a water softener in...
tucker_troy
Sponsored Products
Monroe Two-Light Brushed Nickel Island Pendant
$180.00 | Bellacor
Elita 3 Seat Convertible Sofa-Beige - 18-ELI-N5135-03-0
$509.95 | Hayneedle
Sarah 5-piece Comforter Set
Overstock.com
Westinghouse Rock Music Bellezza 14 in. Ceiling Medallion 7775000
$28.67 | Home Depot
33" Polished Marble 70/30 Offset Double-Bowl Farmhouse Sink - Cream Egyptian
Signature Hardware
Zuo Espresso Leatherette Weave Set of 2 29" High Bar Stools
Euro Style Lighting
© 2015 Houzz Inc. Houzz® The new way to design your home™