Help With Electric Tankless Cold Water Sandwich - Plumbing - DIY Home Improvement | DIYChatroom

Go Back   DIY Chatroom Home Improvement Forum > Home Improvement > Plumbing


Thread Tools Search this Thread
Display Modes
Old 01-31-2016, 09:08 PM   #1
Join Date: Apr 2011
Location: Miami, FL
Posts: 307
Rewards Points: 319

Help with electric tankless cold water sandwich

Please help me comprehend an unfrustrate me with a situation termed "cold water sandwich" (CWS).

In our msster bath is a valve from 2011 that either directs water to the regular showerhead or from overhead. We have an electric, tankless water heater of ample capacity.

My wife or daughter will shower using the regular showerhead and be fine. I will come in 2, 5, 10, 12, etc minutes later to shower, and I get hot water right away for about a minute or 2. I then get very cold water for a while until the hot returns.

I've done some research on the CWS, but it still baffles me as i wait for cold water with a head full of shampoo. How can pipes cool down here in Miamj where our temperatures are always hot. I can understand this occurring in Minnesota, Alaska, etc, but in Miami? I wasnt exagerating about the time gap between the showers. The same situation happens if we reverse the order of showering, with me going first.

Why does this happen? Is it preventable? With a recirc pump perhaps?
NABRIL is offline   Reply With Quote
Sponsored Links
Old 01-31-2016, 09:25 PM   #2
Super Moderator
joed's Avatar
Join Date: Mar 2005
Location: Welland, Ontario
Posts: 20,142
Rewards Points: 31,596
Blog Entries: 11

My novice opinion. The tankless heat only turns on when water flows. If the unit has been off for while some cold water has to flow before the heat kicks back, thus you get some cold through the unit.
joed is offline   Reply With Quote
The Following 2 Users Say Thank You to joed For This Useful Post:
jmon (01-31-2016), NABRIL (02-01-2016)
Sponsored Links
Old 01-31-2016, 09:32 PM   #3
Join Date: Nov 2012
Posts: 4,819
Rewards Points: 3,204

Agree with joed. As far as is it preventable; Possibly, with a recirculating pump as you suggested. It makes sense.
jmon is offline   Reply With Quote
The Following User Says Thank You to jmon For This Useful Post:
NABRIL (02-01-2016)
Sponsored Links

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Similar Threads
Thread Thread Starter Forum Replies Last Post
Shopping for New Electric Water Heater Lots of Questions LeakyHawaiiRoof Plumbing 3 11-02-2014 01:18 AM
Trickle of Cold Water Pioneer Bathtub Faucet egawrons Plumbing 0 10-25-2012 11:24 AM
Warm Water out of Cold Water Outlet mb0709 Plumbing 9 08-26-2012 12:59 PM
Kitchen Faucet Cold Water Runs Hot Mthrboard Plumbing 8 08-02-2009 06:59 AM

Top of Page | View New Posts