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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
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Hi nimble,
Your plumber is correct. This is to protect your plastic pipe should the water ever exceed acceptable temperatures. Usually the 1.5 meters of copper go from the outlet of the HWC to tempering valve and after the tempering the water should be at 55deg anyway.
Also to note is that you need a special tempering valve designed for those temperatures, wetback being an uncontrolled heatsource.
I noticed you said your wetback is 1/2 inch. Wetback should be min. 25mm pipe to allow for thermosiphon activity to take place.
I'm not sure I understand your question about automated temperature, can you please elaborate on this?
Plumber
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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.
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im not sure i read you right here?...Basically i bought a custom made tank and have mounted it on a slope hoizontally in my ceiling space.
I would have thought that you must mount the tank vertical with the outlet/vent being the highest point so if the water does boil the steam can make its way up and out the open vent?...mounting the tank hoizontally on a slope would not put the vent in the uppermost position allowing steam to collect in the tank?...i just thought the vent line must be the highest point in the tank to allow steam to escape stopping any air locks and the such...
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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
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Thank you all so much....obviously i am a little out of my depth here and a little worried >:(............... hopefully i haven taken the correct advice!!!! I plan to have the system connected by a plumber but unfortunately the budget is tight so I have tried to save money by mounting the tank myself
Yes the tank is custom made for a horizontal installation and is installed at about 25 deg slope with the outlet at the highest point where the stand pipe goes out onto the roof.
The HWC is 270L ...how do i calculate the correct ouput size of the wetback???????
By controlling the temperature i mean the water coming from my taps will potentially be very hot, i assumed this temperature would need to be moderated for safety.
I was also advised by someone to run 3/4 inch pipe all the way from the outlet junction directly across to the shower curving it slowly and avoiding any 90 deg bends to maximise pressure. Would this approach be compliant?????
Thanks to you all again
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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.
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I Agree with Robbo 100% on this one. To many ??? Would strongly recommend getting someone that is qualified and has done this before to look at it.
In regards to the temperature Robbo is right you require a tempering valve, as stated in my post before it needs to be one designed for this purpose to cope with the high temperature so not a standard tempering valve.
Let us know how you get on.
Plumber
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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
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BTW the cylinder is an open circuit system i with no coils.
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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=ekEHfihiNz4)
http://www.youtube.com/watch?v=pu3FwgIHsQA (http://www.youtube.com/watch?v=pu3FwgIHsQA)
http://www.youtube.com/watch?v=Xi_p23dce8U&feature=related (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.
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Huh i have to have it installed by a qualified person to get compliance?? I just explained that above??
As far as i know as long as i have the compulsary bits installed by a professional and get compliance from my council i will b insurable why would i not get insurance??
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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?
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not at all sir im not trying to scare you at all just ramming home the need for profesionals to do your work!...and there is a million and one ways to skin the same cat so what we sugguest to you may not be the way another plumber would do the job as there are many unforseen circumstanes at play here and only when the plumber comes to actually see the job can they give you dinifinative answers to your questions....And if your unhappy and believe that the work done by the plumber does not adhere to standards then you have the notirous PGDB at your disposal...And also the choice is in your hands so getting a few quotes isnt going to hurt then you can obvisouley choose the one who seems most suited to the job because there are some very experienced tradesmen out there...easy as pie mate and for your wood burrner you should do some home work and just ring some of the manfactures of these wet back systems and they should be able to put you right i guess.
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but there cool vids anyways...but truley mate im only conserned for your own safety not out to scare ya just worried.
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All fair enough points mate , video's definitely make you see why a plumber is required for this kind of install!!!
It looks like this was my mistake.... i thought part of this site was was for the public to get plumbing advice? To be honest it's kind of confusing
i partake in other forums some public some private. Are you saying that these forums are for the sole use of plumbers or not?
If the public are allowed here, they must only be here but to seek advice, gather information and become wiser :)
Anyways all this aside i should at least share what i have learnt in fact I'm worried now my tank is wrong. I have drawn my custom made tank and attached it can someone confirm it is a suitable configuration for a low pressure open vented system.
The reasons i chose the low pressure open vented system are:
Im on tank water without mains pressure
Much cheaper than closed loop systems
wetback and solar work together well to provide heating and hot water
very cheap to run if you have supply of wood
reliable
You all have highlighted the potential dangers of a poorly designed system and importance
of a professional balanced installation. I would be interested to hear any other downsides to this type of installation.
I would also be interested in your opinions on which type of solar/wetback system you think is:
Best overall
Most cost effective
Safest
Obviously the downside will be water pressure. Does raising actually increase your pressure much?
Thanks for your Help and Concern
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Hi nimble
You are definitely right. Plumbers Forum is designed for Tradesmen to interact and share knowledge but also a place for the public to turn to for advice. No one is trying to prevent you from becoming wiser (I beleive the cold war is over), there is only a concern about the nature of the job. And honestly I can understand Thunderheads criticism due to this fact.
Your hot water cylinder. Who designed it and who built it? Because you state it was custom made, a HWC must comply to G12 and engineers specifications also 2712 Standard code in NZ. The element and thermostat must be at a height specified by the code to suit application, Tank must have a biosafe etc.. These are only a few things you need to be aware of. Im sure you know these things already but there are only a hand full of tank manufacturers in NZ that custom make these tanks to the standard.
No there are no disadvantages with low pressure. In fact you save water, your tank lives longer and being open vented no issues with valves and maintenance. Correctly installed its also safer then mains. Combination Wetback / Solar makes it cheap to run. I personally have one and I love it.
There is more concern in the state the Cylinder is installed, being horizontal (or @ 20 deg) your layers of heat (stratification) are much closer to each other then they would be being vertical hence less efficient, other nuisances such as hot/cold water patches could occur when showering, so even more important make sure you have a diffuser on your returns.
All your Solar / Wetback and cold come in through one end, I assume the thermostat is also on that side, that's where there is a downside of having everything open , when your showering you will introduce cold water into the tank and your probe / thermostat could get a wrong reading and end up switching on your element even though there is enough hot water in the tank available.
another thing you need to be aware of is filtration. Being on tank water means a lot of debris will get pumped into the tank. This will damage your wetback (usually steel heat exchanger) and your solar panels. Also looking at the angle of your HWC most of it will end up slugging in the bottom corner of the tank, not really good.
My personal favourite is a Mains Pressure tank for Domestic supply, two coils, one for Solar and another designed for wetback. Wetback connected as low pressure. Glycol on both indirect wetback and Solar installations. It's more efficient and I protect my panels and wetback long term. The water will also taste better :P Merto Wetbacks is what I recommend my clients.
Hope this helps. Once your finished please let us know how efficient the system is. I'm very keen to find out.
Regards Plumber
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Thanks Plumber, proper discussion and good advice!!!!!!!!!!
Who designed it and who built it?
Paid $1200 to a local importer of solar panels. He designed it and had it manufactured in the south Island.
Our low ceiling height would only allow for much smaller vertical tank. I really wanted at least 200L i thought it makes sense
that with a large insulated tank I can store more energy for cloudy days in the summer or warmer days in the winter.
All your Solar / Wetback and cold come in through one end, I assume the thermostat is also on that side
I think this is marked on the Diagram as pocket probe?? port located at the end with most the feeds.
Is it possible o have a longer probe thermometer...would this make a difference?
thermostat could get a wrong reading and end up switching on your element
The diagram doesn't show actual angle my tank. It's much more than 20 deg i will measure tomorrow.
I'm hoping controlling the power supply with a timer will give me some control over when the element can operate.Is this a practical approach?
another thing you need to be aware of is filtration
I have looked a a few things that will hopefully help.
Tipper on end of spouting to catch sediment.
Wire along the pitch of my roof to annoy birds.
I'm unsure on this piece of advice????? Limestone in the bottom of my main tank to neutralise acid rain and extend the life of my tank??
Ultimately would I want some kind of micro particle filter? These are expensive!!! Is there any more simple or cheaper alternatives??? Some kind inline filter that can be cleaned changed manually? How much do filter systems cost?
Also looking at the angle of your HWC most of it will end up slugging in the bottom corner of the tank, not really good.
This does concern me but i guess this can happen to a vertical system too over a long period of time. It's my understanding that this system is relatively safe as it is vented under low pressure in a relatively strong cylinder.
As i have explained i will be having this installed by a professional....... i also like the metro wetbacks they seem very good value. I only have 1.7 Hectares (not 2) so i beleive unless my wood burner has an oven too i will be limited to by the enviromental laws as to which fireplace i am allowed Is there any way around this it seems unfair since the fireplace will be multi purpose and i am planting a sustainable wood source.
I am planning to plant and already cutting down Eucalytus. I beleive properly dried this is a nice source of fuel.
your opinions much appreciated
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Not a problem nimble,
Paid $1200 to a local importer of solar panels. He designed it and had it manufactured in the south Island.
Our low ceiling height would only allow for much smaller vertical tank. I really wanted at least 200L i thought it makes sense
that with a large insulated tank I can store more energy for cloudy days in the summer or warmer days in the winter.
Ok, im guessing it was SH in the south Island. I hope so anyway they are reliable. The bigger the better, your right.
I think this is marked on the Diagram as pocket probe?? port located at the end with most the feeds.
Is it possible o have a longer probe thermometer...would this make a difference?
The pocket probe is not the thermostat. The probe controls the solar heating system and the solar heating controler then controls the element. Every HWC is also manufactored with an additional thermostat and Bio Safe.
The diagram doesn't show actual angle my tank. It's much more than 20 deg i will measure tomorrow.
I'm hoping controlling the power supply with a timer will give me some control over when the element can operate. Is this a practical approach?
Not the Ideal solution but that will work to an extent.
I have looked a a few things that will hopefully help. Tipper on end of spouting to catch sediment. Wire along the pitch of my roof to annoy birds.
I'm unsure on this piece of advice?? Limestone in the bottom of my main tank to neutralise acid rain and extend the life of my tank??
Ultimately would I want some kind of micro particle filter? These are expensive!!! Is there any more simple or cheaper alternatives??? Some kind inline filter that can be cleaned changed manually? How much do filter systems cost?
Have a look at your foot valve in the tank that should have a strainer with at least 50 microns. All the above mentioned will help but you will still need a 10 - 20 micron strainer on your pump outlet. Cant think of the manufacturer at the moment but there is an outfit in Albany Auckland that does them in a cartridge form. They are not expansive and work well on pumps. Best ask your local merchant. If I can remember the name I will post it here. cost somewhere between $150 - $250 by memory, its been a while.
This does concern me but i guess this can happen to a vertical system too over a long period of time. It's my understanding that this system is relatively safe as it is vented under low pressure in a relatively strong cylinder.
As i have explained i will be having this installed by a professional....... i also like the metro wetbacks they seem very good value. I only have 1.7 Hectares (not 2) so i beleive unless my wood burner has an oven too i will be limited to by the environmental laws as to which fireplace i am allowed Is there any way around this it seems unfair since the fireplace will be multi purpose and i am planting a sustainable wood source.
I am planning to plant and already cutting down Eucalytus. I beleive properly dried this is a nice source of fuel.
Once your water is filtered properly there should be less concern, I would still flush it out once a year or so depending on water quality. Yes "environmental laws" we love them don't we? I think I will leave it at that.
Will try to post the name soon.
Plumber
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Cheers Plumber. I feel more confident now i am on my way down the right path and know enough myself to make sure i find a good plumber.
I spose it's good news that the pocket probe isn't the thermostat and the tank was probably made by a reputable company. Then hopefully the Thermostat is in more a sensible position considering the tank was produced to be a horizontal tank.
Is the $200 cartridge a consumable item?? If so how often will it need replacing??
Also when you say diffusers will be important ...Do these diffuse the hotwater going back into the tank more evenly so they dont stir it up too much. Why is this important?
When you say flush out the system, Is this done chemically or by just draining down the system. Is there need for some kind of valve or tap to drain the system down or is just turning on all your hot taps the quickest way?
Cheers plumber.....Is it ok if i post some links to some sources of information and documents i have found useful along the way?
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Hey Plumber
I got a reply from who i bought the cylinder from. It was manufactured by Superheat and the thermostat is located as per the diagram. Does this make a difference??
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hi nimble,
Superheat are brilliant, marine grade Stainless and they put the diffuser on the return for you. That's great! Thermostat also in the right place cant complain.
Yes your right, if you stir up your layers of heat you will have a less efficient system and also get cold patches while showering.
The cartridges are washable, Monday when I'm back at the office ill look up the details for you and post them here.
By flushing out I mean simply clean out your wetback and panels by completely draining the water out of the system twice. You will be surprised how filthy water can get. When installing the system try not to create any water traps, that's logical on the wetback ;D. Also don't forget a drainpoint on the wet back return, many forget that.
Would be great if you could post any details, cheers
Plumber
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Found those details:
Hydroflow DistributorsHydroflow Distributors
221 Bush Road Auckland 0632 - (09) 415 5585
Open Weekdays 8am-5pm
The product I used a few years back is IF25RD comes with different microns as a cartridge.
Hope this helps
Plumber
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Thanks very much mate. You have been such a huge help.
Today panned out as expected, met with plumber to get a quote for the install.
He's trying to tell me diffusers are just a gimmick and i wont need them...so frustrating.
This is exactly why i came here cause as i pointed out to members of your board that it's hard to get good advice.
Just contacting a registered plumber doesn't always mean you get the best advice. Thanks to the forum i'm now an
informed customer that is still going to pay a plumber for his work...win/win
Thanks again
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Always our pleasure nimble and all the best.. :D