Hi there

We have built a roofspace low pressure wetback/ solar capable HWC system. As i understand the wetback 1/2 inch pipe needs to be all copper, a plumber doing some other work on the house mentioned all other feeds to and from the tank should have 1.5 m of copper pipe before it switches to butaline. Could someone please confirm the distance and which feeds are required to be all/part copper?

I also wondered if anyone new wether a temperature control system would be required for compliance and how much a basic how water automated temperature mixer system will cost to install??

Many thanks forany advice or assistance

Linkback: https://www.plumbers.nz/solar-heating-and-heat-pumps/9/low-pressure-weback-solar-question/605/

Hi there , thanks for your reply. Your right I dont completely understand this.
Basically i bought a custom made tank and have mounted it on a slope hoizontally in my ceiling space.
It is a low pressure system and has inlets and outlets for both solar and wetback. Its located about 3m from and above my fireplace.

I'm assuming i will need some sort of device to moderate the temperature of my hot water as potentially the water in my tank could boil!!

The custom made tank was designed fro wetback so the fitting size should be 25mm i will check. Would the coldwater inlet pipe need to be copper for the 1.5m at the tank end or is it just the wetback ,solar and outlet that need to be copper?

Thank you very much for your help.

Just adding onto Thunderheads quote, was the tank designed to be installed Horizontally?, I agree this doesn't sound right. No there isn't a requirement to install copper on the inlet but its good practice. Control for wetback? hmm No... (unless you are using a pump) If your wetback is working via therosiphon then it cant be controlled. That's why wetbacks are sized correctly depending on the size of the HWC. So exactly that does not happen. Make sure its open vented and no tempering valve is blocking the passage, refer to NZ standard AS/NZS 3500.4:2003 for correct installation methods. The design and installation can change depending on if you are heating directly or via a heat exchanger.

Just a thought in regards to your 15mm connections. Are you sure that's not the defuser for the solar  ?

Hope this helps

hi, i`m reluctent to chip in here but if i was you i would contract a reputable plumbing and heating company to carry out the work that way they would take full responsibility and you would have a gaurantee, reading your posts you could well finish up with a BOMB, i think that you are also refering to a tempering valve to control the water temp at the faucets and showers which would be mandatory,have you applied for a council permit you will probably need one. Just remember if you do anything yourself that go`s wrong your insurance co will not cover it and the P.G.D.board may procecute you. Just friendly advice,good luck. 

Cheers for the heads up....yes i have council permission and Yes i definitely will have The HWC connection, Wetback and solar installed by a plumber.

My father is an engineer and is helping me with stuff,  our builder  built the load bearing beams for the cylinder. The guy who organised the HWC and solar equipment  helped with the design for connections on the custom cylinder and placement . So i am quite confident we are heading along the right path.
I have not bought the wood burner yet and i'm aware i will need to size the wetback output accordingly
We have relocated a house in the Kiapara district and  I have double and triple checked with the council that they are only wanting to inspect and  need certification for the new HWC connection,new fire, wetback + fitting the new shower mixer (we are moving the shower). All the rest of my plumbing is apparently being treated as existing.   The reality is it's very old and tired and i want to replace lot's of it, we have done lot's of basic butalyne hot and cold water plumbing under our previous house but never run pipes from the roofspace down.  Is it Feasable to do this ourselves??

Any tips for running pipes inside walls??

Many Thanks

help and advice can only go so far mate before we have to charge you for our knowledge...i understand you wanting to do things on the cheep not paying the correctly qualified people to do the job correctly...but for a system that will be in place for the next 15years or so the expense you pay now...you will recoup in the future by having a correctly installed system with the correct warrintys and insurance in place...what you fail to see is that hot water storage systems can be deadly if not installed correctly...are you prapared to risk you and your familys health and safety for a coupple of grand?


watch these clips showing examples of what can and will happen in a worst case example

http://www.youtube.com/watch?v=ekEHfihiNz4

http://www.youtube.com/watch?v=pu3FwgIHsQA

http://www.youtube.com/watch?v=Xi_p23dce8U&feature=related

Im not trying to scare you just trying to say...no offense intended but please get a plumber to install this doubble system for your own safety.

In my experience not all trades people are as knowledgeable or professional as they make out. I am here trying to get the best advice to ensure who ever  i do employ does things the best way possible. It sure seems like your trying to scare me....why?

but there cool vids anyways...but truley mate im only conserned for your own safety not out to scare ya just worried.