Plumbing in a solar hot water system , please help .

[duggie]

G'day swaggers , I could use some help with some plumbing I need to do .


I have bought and fitted a rooftop Evacuated Glass Tube Solar Hot Water Kit and I am now about to plumb this system into my house plumbing .

I would love to be able to plumb the rooftop system ( RTSS ) into my existing 200ltr Electric Hot Water system and use the  Electric Hot Water system ( EHWS ) as the supply to the house .

I have a few ideas of how this may work but I am not sure if either will work without causing problems .

One way I think that may work is if I leave the cold in B1 and the hot out A1 as it stands at the EHWS and plumb a line from the second inlet B2 of the EHWS to the outlet C2 of the RTSS

And run another line form the second outlet A2 of the EHWS to the inlet C1 of the RTSS .


This would allow the full system to be topped up with cold water and mixing with the hot water from the RTSS when hot water is been used for showers and the like .

I am going to plumb in a solar powered pump  into the line going from  A2 of the EHWS to the inlet C1 of the RTSS , this would allow the hot water to circulate during the daylight hours and keep the EHWS full of hot water .


I have another idea but it requires more plumbing and several non return valves and presser reducers .

I have no problem with doing this , but is there a simple way or better way to do this , I would be grateful of your help . ?

[Fizzie]

We did this years ago & never looked back

Did your unit come with a 4 way valve / conversion valve, to have both hot & cold water connected to it

Got to go out in a minute so no time to take photo's but I'll talk to you again this arvo.

[duggie]

We did this years ago & never looked back

Did your unit come with a 4 way valve / conversion valve, to have both hot & cold water connected to it

Got to go out in a minute so no time to take photo's but I'll talk to you again this arvo.

What is this 4 way valve you speak of ?

Any and all help is/will be greatly appreciated .

I only want to do this once , and I want to get it right the first time .

[rags]

Read this book
http://www.energyrating.gov.au/sites/new.energyrating/files/documents/Solar-and-heatpump-HWS-plumber-training-handbook.pdf

[duggie]

Read this book
http://www.energyrating.gov.au/sites/new.energyrating/files/documents/Solar-and-heatpump-HWS-plumber-training-handbook.pdf

Thanks Rags ,

Looks like I need to :

run B2 to C1  - Cooler water from EHWS to the inlet on the RTSS

run A2 to C2   - Hot water  from RTSS to top of storage EHWS


Makes sense as the household will be pulling the hot water and the roof top solar system will be been topped up with the tempered water at the bottom of the hot water system ( power will be turned off unless needed )

[Fizzie]

What is this 4 way valve you speak of ?

T'is one of these, or something similar

[Fizzie]

Our set-up - evacuated tubes on roof (funny that! ), feeding a normal ~350l electric hot water tank.

Cold water runs through 4-way valve, circulating pump pushes it up to roof to be heated, then back down, through 4-way valve into base of tank, then is drawn from top of tank into house.

Bit Heath Robinson'ish (hey, any CT owner should be able to relate to that! ), but the various taps allow any section to be isolated - I can turn off the water each side of the pump & remove / replace that if necessary, completely disconnect either the roof tubes or the tank & still have hot water. Tank is still connected to 240v, but switched off in fuse box. If we have heavy cloud / rain (someone must remember that, mustn't they ), then by about the 3rd day, water has usually dropped to about 45`, so it's simply switch it on in fuse box & it boosts back up to 55 - could go higher but I'm a cheap are who doesn't want to spend the $ . We usually finish up boosting ~3 times a year!

System is set to allow max 90` on roof, so pump switches on & circulates water when it reaches that.

[Fizzie]

& it works!

T1 is approx temp on the roof - heat sensor just strapped on the pipe, not actually in the water!

T2 is external temp at base of tank

T3 is strapped to pipe leaving the tank to enter house

Any questions please ask & I'll try to help

[Fizzie]

Extra one showing the water flow.

Red dashed line is so the water can be diverted straight into the house, not via the tank.

[duggie]

Thanks Fizzie,

I will have a good look at the setup that you have posted up and see if I can make it work .

Reading through the attached booklet that Rags posted I have drawn up a plumbing plan that should/may work . But before I get into the plumbing I will ( as stated ) have a good look at your system .

[duggie]

G'day Fizzie ,

I think I have mapped out your plumbing system correctly .

Questions :

The hot water feed into the 4 way valve . Does this feed hot water into the HWS or does it get circulated through the RTSS ?

Cold water runs through 4-way valve, circulating pump pushes it up to roof to be heated, then back down, through 4-way valve into base of tank, then is drawn from top of tank into house.

The Cold Water is only feeding to the RTSS or does it also feed the EHWS ?

[Fizzie]

G'day Fizzie ,

I think I have mapped out your plumbing system correctly .

Questions :

The hot water feed into the 4 way valve . Does this feed hot water into the HWS or does it get circulated through the RTSS ?

Into the tank

The Cold Water is only feeding to the RTSS or does it also feed the EHWS ?

Mainly the roof, but will also go to the tank

Here's their plumbing diagram & also the instructions. I've got a drawing of my set-up but can't work out how to attach it?

[duggie]

You know I am constantly amazed with this wonderful forum , .

I post up this solar hot water post with some hope that I may get some assistance from a forum member or members .

I received information that has steered me in the direction that I needed to go , but I hit a snag .

Fizzie posted up about a 4 way valve , I went to all of the plumbing suppliers , photo in hand , and not one of the local mobs could supply .

I have since spent several hours trying to google up this 4 way valve that is need to plumb in my system , but no luck . I saw thousands of valves , but not what I need .

Bugger it , I decided to send a PM to Fizzie and ask again for some help in finding this valve .

Within minutes I received a reply from Fizzie ( Graeme ) with who supplied him with his solar kit and the link to the exact 4 way valve needed .

Thanks Fizzie ( Graeme ) for your time and effort , owe you a few beers . 

[Fizzie]

owe you a few beers . 

Happy to help mate

Now are you delivering, or do you expect me to come pick 'em up

& don't suggest SwagMail - I think there's a more than fair chance that they'd evaporate on the way

 

[duggie]

Happy to help mate

Now are you delivering, or do you expect me to come pick 'em up

& don't suggest SwagMail - I think there's a more than fair chance that they'd evaporate on the way

 

We are bound to run into each other a some time .

[Fizzie]

So how'd you go, Duggie

[duggie]

So how'd you go, Duggie

Yep , onto it .

I tried contacting the mob that supplied your system , they have been closed down .

But during my inquiries I was put onto another supplier and on their web site is how to make this 3 or 4 way cross over fitting , so I have bought all the crap I need to carry on with the fitment but it is bloody wet up here and I ain't going up on the roof when it is wet .


I will post up some photos when I have finished the install .

[Fizzie]

Sorry about the bum steer - wish people would close down their websites when they shut up shop

Good to hear it's all sorted though