Reply
 
Thread Tools Display Modes
 
Old 09-18-2018, 09:50 PM   #1
Skoolie
 
bigskypc50's Avatar
 
Join Date: Dec 2016
Location: Anaconda,MT
Posts: 191
Year: 1995
Coachwork: Amtran
Chassis: International
Engine: DT466 Turbo
Rated Cap: 70
Two tankless water heaters?

Greetings everyone I have very cold ground water and very low pressure where I live. I have not had good luck with tankless water heaters in the past, so I am wondering if I bought two of the Excel tankless ventless water heaters and fed the output of the first unit into the second one if I could get good nice hot water out of that at the max 1.6GPM flow they are rated for?
bigskypc50 is offline   Reply With Quote
Old 09-18-2018, 09:55 PM   #2
Bus Geek
 
Tango's Avatar
 
Join Date: Mar 2011
Location: Houston, Texas
Posts: 7,993
Year: 1946
Coachwork: Chevrolet/Wayne
Chassis: 1- 1/2 ton
Engine: Cummins 4BT
Rated Cap: 15
You might check with "Ol' Trunt" (aka; Jack). As I recall, he discovered that you can over pressure the system if you are not careful and blow stuff up with too much heat/steam pressure. But...(also as I "recall") I think he figured out a fix.
Tango is offline   Reply With Quote
Old 09-18-2018, 10:07 PM   #3
Bus Crazy
 
milkmania's Avatar
 
Join Date: May 2015
Location: Oklahoma aka "God's blind spot"
Posts: 2,307
Year: 1989
Coachwork: 1853FC International/Navistar
Chassis: 35' Retired Air Force Ambulance
Engine: DT466, MT643
Rated Cap: 6 souls and a driver
Quote:
Originally Posted by bigskypc50 View Post
Greetings everyone I have very cold ground water and very low pressure where I live. I have not had good luck with tankless water heaters in the past, so I am wondering if I bought two of the Excel tankless ventless water heaters and fed the output of the first unit into the second one if I could get good nice hot water out of that at the max 1.6GPM flow they are rated for?
personally, I've got great pressure... But, being the inquisitive one, I've experimented with my eccotemp L5.

I've got a portable hottub, and had a harbor freight transfer pump 12volt laying around... I plumbed to pick up water from the tub, feed through the heater, and back out to the tub... worked awesome! now, I did not run it back through a shower head to see if I'd like the pressure... but, what I saw on the outlet hose was similar to my regular water supply pressure.

Bryan at Eccotemp showed me how to adjust the propane burner and water pressure inlet to a range outside of factory specs, with 2 adjustment screws... so, that along with a standard garden hose ball valve... I can hit 192 degree outlet temps!

I know it doesn't answer your original question... but it might give you an idea what your heater is capable of.
personally, I think hitting the second heater with hot water isn't going to help you much. there might even be a high limit switch incorporated in your heater.

HF pump $39.99... wait for a sale!
https://www.harborfreight.com/12-vol...ump-63324.html

garden hose ball valve
https://www.amazon.com/Gilmour-Conne.../dp/B0006U66B6

also created a PEX manifold with Shark Bite ball valves and fittings to go to the shower and clothes washer... has worked great for over 2 years
Shark Bite fittings are awesome, because they're reusable!
__________________
I once complained I had no shoes....
Until I met a man with no feet
milkmania is offline   Reply With Quote
Old 09-19-2018, 12:01 AM   #4
Bus Crazy
 
ol trunt's Avatar
 
Join Date: Apr 2012
Location: So Cal
Posts: 2,169
Year: 1935
Coachwork: Superior
Chassis: Chevy
Engine: 317 ci/tid / Isuzu
Forget the second water heater. Remember, the Ecotemp heats ambient temp water by a set amount (can't remember the specifics). Therefore the hotter the water going in the hotter the water coming out. I put a recirculating circuit on my ecotemp to assure me of hot water nearly instantly. The problem was that as input ambient rose in temp so did output--until my hot water lines grew soft and finally gave up!?! I solved my problem by installing a thermocouple on the outlet that shut down the ecotemp at the temp I wanted. That works great. You migh consider a dedicated hot water tank coupled with a thermostat and a recirculating valve. I use a dedicated water pump one for hot and one for cold. This arrangement provides me with flawlessly regulated hot water temps and has done so for a couple of years.
Jack
ol trunt is offline   Reply With Quote
Old 09-19-2018, 12:46 AM   #5
Almost There
 
Join Date: Feb 2018
Location: Fort Collins, CO
Posts: 71
Bigsky,


Be careful of overheating the water. Even if the bulk of it doesn't boil (reach 212 F), there's a phenomenon called critical heat flux - basically a really thin layer of water next to the hot outer wall of the pipe (that's being heated by propane) can boil locally, creating a vapor gap, which then insulates the water in the center of the pipe. The temperatures inside the pipe can jump up super rapidly, ultimately causing the pipe to fail from excessive temperature of excessive steam pressure.


Short version: rapid overheating = pipe bomb. Not recommended.
__________________
Professionally converting vehicles and making custom furniture with a combined 14 years of mechanical/electrical engineering experience.

https://www.thunderstruck-studios.com/
ThunderstruckStudios is offline   Reply With Quote
Old 09-20-2018, 10:24 AM   #6
Bus Crazy
 
Njsurf73's Avatar
 
Join Date: Jan 2017
Location: Massachusetts
Posts: 1,467
Year: 2002
Coachwork: Bluebird
Chassis: Bluebird
Engine: 5.9 Cummins 24v
Rated Cap: 72 pax
What about a small (20 gallon) holding tank with a water pump. Would solve the low pressure issue and should allow the water to at least come up to ambient temperature and you don't have the worry of overpressure.
Quote:
Originally Posted by bigskypc50 View Post
Greetings everyone I have very cold ground water and very low pressure where I live. I have not had good luck with tankless water heaters in the past, so I am wondering if I bought two of the Excel tankless ventless water heaters and fed the output of the first unit into the second one if I could get good nice hot water out of that at the max 1.6GPM flow they are rated for?
Njsurf73 is online now   Reply With Quote
Old 09-20-2018, 12:44 PM   #7
Bus Nut
 
Rivetboy's Avatar
 
Join Date: Jul 2017
Location: Huntington beach
Posts: 448
Year: 1991
Coachwork: Bluebird
Chassis: T/C 2000 28 foot Handy Bus
Engine: Cummins 5.9 Mechanical
Rated Cap: 2
Quote:
Originally Posted by ol trunt View Post
Forget the second water heater. Remember, the Ecotemp heats ambient temp water by a set amount (can't remember the specifics). Therefore the hotter the water going in the hotter the water coming out. I put a recirculating circuit on my ecotemp to assure me of hot water nearly instantly. The problem was that as input ambient rose in temp so did output--until my hot water lines grew soft and finally gave up!?! I solved my problem by installing a thermocouple on the outlet that shut down the ecotemp at the temp I wanted. That works great. You migh consider a dedicated hot water tank coupled with a thermostat and a recirculating valve. I use a dedicated water pump one for hot and one for cold. This arrangement provides me with flawlessly regulated hot water temps and has done so for a couple of years.
Jack
Good Morning Jack,

So my undestanding is you have an auxillary water tank with a pump connected to the output side of the water heater . The water heater and the pump to recirculate hot water through the tank are on a thermostat.
Do I need more coffee?
Is the recirculating valve supposed to read "pump"

Joe
Rivetboy is offline   Reply With Quote
Old 09-24-2018, 12:42 PM   #8
Skoolie
 
bigskypc50's Avatar
 
Join Date: Dec 2016
Location: Anaconda,MT
Posts: 191
Year: 1995
Coachwork: Amtran
Chassis: International
Engine: DT466 Turbo
Rated Cap: 70
Wrote the manufacturer. They said it should not be a problem with that setup.

Hello Eric,

Yes you can connect them in series to achieve a higher delta in temp increase for 1.6gpm.

You can tinker with the gas knob and the water flow knob for the desired performance

You can buy them at this link:

http://excelonlinestore.com/excel-16...p-ventfree-lpg

Excelamerica , LLC
Fernan Ech Usher
6010 NW 99 Ave
Unit 107
Doral, FL 33178
USA

gasflex is a registered trademark USPTO
bigskypc50 is offline   Reply With Quote
Old 09-24-2018, 03:28 PM   #9
Bus Crazy
 
ol trunt's Avatar
 
Join Date: Apr 2012
Location: So Cal
Posts: 2,169
Year: 1935
Coachwork: Superior
Chassis: Chevy
Engine: 317 ci/tid / Isuzu
More coffee----

2 pumps, 1 hot, 1 cold both from same tank.

water heater output goes to both the faucets and to a solenoid valve which diverts hot water back to main tank. Water can flow through either or both. As long as there is water flow and pressure, the heater will stay lit rather than constantly cycling. This assures hot water "instantly".

These heaters maintain a temp differential based on the ambient temp of the inlet water. As the main tank drew down, its ambient temp went up due to the recirculation of hot water --all the way up to 150 degrees F. That was hot enough to melt the joints on my PVC water pipes and make a mess. With a thermocouple switch on the heater output side I am able to control the upper temp limit within a couple of degrees without nearly as much heater cycling.

If you are stuck with very cold inlet water, a 2 tank system (1 hot, 1 cold) would hasten getting your inert water temp to within the desired heater temp differential. Ha! Clear as mud.
Jack
ol trunt is offline   Reply With Quote
Old 09-24-2018, 09:22 PM   #10
Bus Crazy
 
Join Date: Aug 2014
Location: SW New Hampshire
Posts: 1,198
Quote:
Originally Posted by ol trunt View Post
These heaters maintain a temp differential based on the ambient temp of the inlet water. As the main tank drew down, its ambient temp went up due to the recirculation of hot water --all the way up to 150 degrees F. That was hot enough to melt the joints on my PVC water pipes and make a mess. With a thermocouple switch on the heater output side I am able to control the upper temp limit within a couple of degrees without nearly as much heater cycling.Jack
Do I misunderstand your setup, or are you at risk of having 100 degree water coming out of the cold faucet? Not conducive to a good shower if both faucets are the hot faucet.
dan-fox is offline   Reply With Quote
Reply

Thread Tools
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


» Featured Campgrounds

Reviews provided by

Powered by vBadvanced CMPS v3.2.3

All times are GMT -5. The time now is 07:00 PM.


Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2018, vBulletin Solutions, Inc.