Flow/pressure problems-Multi tank passive

Users who are viewing this thread

natec904

New Member
Messages
9
Reaction score
0
Points
0
Hi all, firstly I am a master electrician not a plumber. Electrical theory I am good with but have absolutely no training or technical knowledge of plumbing systems.
I designed and built a three tank solar collector which I installed in series with my existing electric heater. My theory is that when solar falls short electrical would act as back-up.

I cut the 3/4" cold supply to the electric and sent it to the solar. The solar I piped in 1/2" cpvc and returned the hot side to the electric cold supply inlet.

I installed two isolation valves and a bypass valve so I could isolate the solar in the event of problems and go to bypass and essentially be back where I was with the exception of a reduction from 3/4" pvc to 1/2" cpvc at the electric cold supply inlet.

I piped the solar in 1/2" to slow the flow so as to collect more heat and so expected some flow reduction but upon my first shower I was in for a real depressing surprise. There was barely enough (pressure/flow? ) to climb from the spout to the shower head.

In bypass there is a noticable drop in (pressure/flow?) but is livable.

I isolated both supply and return pipes to / from the solar, good flow in both.
There is good flow through the solar.

So my initial questions are:
A) Do 90's (slow/restrict) (flow/pressure) ?
B) What is the effect of line length?

Any other constructive criticism would be greatly appreciated.

PS: I am in Florida and the collector tanks are (2) 40 gal. well pump tanks and (1) 40 gal electric heater tank stripped out of the cover and insulation.
 

Leejosepho

DIY scratch-pad engineer
Messages
2,483
Reaction score
0
Points
36
Location
200 miles south of Little Rock
Website
www.nonameyet.org
So my initial questions are:
A) Do 90's (slow/restrict) (flow/pressure) ?
B) What is the effect of line length?

PS: I am in Florida and the collector tanks are (2) 40 gal. well pump tanks and (1) 40 gal electric heater tank stripped out of the cover and insulation.

Yes, 90s and long lines can increase flow-reducing friction. You might have been better off with multi-tubed heat exchangers with manifolds on their ends so you could have reduced flow within those individual lines while still having normal-sized lines running to and from the exchanger.

I once did what you have to get hot water on our houseboat in the Keys. I wrapped a 30-gallon tank from the bottom (inlet) to the top (feed) with 3/8" copper tubing as it supply line, then painted the assembly black and mounted it on the roof under plexiglass. We only had a small demand pump in the overall system, but we got plenty of hot water at the shower. One factor you might have is the matter of pushing water all the way up to your tanks and then against the weight of the water in them, and that is why I supplied my own tank from the top.
 

NHmaster

Master Plumber
Messages
3,176
Reaction score
5
Points
0
Location
S. Maine
Too many elbows will cause a restriction but the biggest problem is with using cpvc. solar temps can and do get way way above what cpvc is rated for, and that is true for pex as well. All feed and return piping should be in copper. All solar components need to be rated for 300 degrees.
 

Master Plumber Mark

Sensitivity trainer and plumber of mens souls
Messages
5,533
Reaction score
354
Points
83
Location
indianapolis indiana - land of the free, home of
Website
www.weilhammerplumbing.com
solar panels.....

if you piped the water directly to the solar panels,
then back down to the water heater...

most panels that I remember actually reduced
down to an array of 3/8 copper tubeing going
from the bottom to the top of the panes from a one inch manifold.....


so I would venture to say that the restriction is going
to be in the panels cause they were probably not
designed for this kind of high flow application......


if that is the way its is installed,
when you want to take a shower you will have to bypass the panels

your wife is gonna love that
 
Last edited:

protech

Master plumber
Messages
53
Reaction score
0
Points
6
Location
Central Fl
Website
www.protechplumbing.biz
If you could post a picture, I could assist you better.

What would happen to the voltage(like pressure) in an electrical circuit if you undersized the wire(pipe) for the amount of amperage(flow) you are trying to run? Voltage drop(flow pressure drop) and wire damage(pipe cavatation).

Do you understand?
 

protech

Master plumber
Messages
53
Reaction score
0
Points
6
Location
Central Fl
Website
www.protechplumbing.biz
That's not true for the type of collectors he's using nhmaster. High volume ungalzed collectors will not stagnate above 170F. You would be correct if he used glazed flat plate or evacuated tube collectors though.

Too many elbows will cause a restriction but the biggest problem is with using cpvc. solar temps can and do get way way above what cpvc is rated for, and that is true for pex as well. All feed and return piping should be in copper. All solar components need to be rated for 300 degrees.
 
Top
Hey, wait a minute.

This is awkward, but...

It looks like you're using an ad blocker. We get it, but (1) terrylove.com can't live without ads, and (2) ad blockers can cause issues with videos and comments. If you'd like to support the site, please allow ads.

If any particular ad is your REASON for blocking ads, please let us know. We might be able to do something about it. Thanks.
I've Disabled AdBlock    No Thanks