about to get solar BUT

bamboozle

got a list of the following optional 'extras' from the supplier, can anyone advise which are necessary/advisable?

400L Triple Coil stainless steel cylinder (instead of a 300L copper tank, price difference of 800)
Solar Roof bolts
DN 16 Stainless steel Pipe 15m
Fittings for ss pipe
22mm - 3/4" DN16 to panel
Immersion heater for cylinder

thanks

homer911

bamboozle wrote: »

got a list of the following optional 'extras' from the supplier, can anyone advise which are necessary/advisable?

400L Triple Coil stainless steel cylinder (instead of a 300L copper tank, price difference of 800)
Solar Roof bolts
DN 16 Stainless steel Pipe 15m
Fittings for ss pipe
22mm - 3/4" DN16 to panel
Immersion heater for cylinder

thanks

My personal thoughts...
I dont think the stainless steel cylinder is worth it - I presume the copper cylinder is factory insulated. Some people say the stainless steel holds the heat better and lasts longer, but you are also adding 1/3 to your storage capacity so should really be increasing your panel size

The immersion heater was recommended by my installer to ensure that the temp got to 60C for 30 minutes a day to prevent Legionnaires Disease

The Stainless Steel pipe is a bit like shower hose and is very flexible and therefore easier to fit. You cant use the plastic pipes and copper requires joints etc which could leak in a pressurised system. Its important to have the best insultation on the pipe to prevent loss between the panel and the tank (and back)

Mellor

bamboozle wrote: »

got a list of the following optional 'extras' from the supplier, can anyone advise which are necessary/advisable?

400L Triple Coil stainless steel cylinder (instead of a 300L copper tank, price difference of 800)
Solar Roof bolts
DN 16 Stainless steel Pipe 15m
Fittings for ss pipe
22mm - 3/4" DN16 to panel
Immersion heater for cylinder

thanks

The only one that looks optional to me is the steel cylinder.

The rest might be extras to the price you were quoted, but not really optional. You need them, but feel free to shop around

heinbloed

Changing the copper cylinder for a stainless steel cylinder makes sense since these stainless steel cylinders come usually with a 10 year guarantee. (Ask for that !)And if you use stainless steel pipes then the copper will be attacked by the "better" metall, make sure you use stainless steel or glass in the collectors as well. Otherwise you would have to use a rust inhibitor or an anode.Keep the system simple.The standard insulation I see here with 40-60mm of PU foam on copper cylinders is far to little. Professionals use 100mm for internal installations.For external installations this would have to be increased further.Keep in mind that the surface/content ratio is better with a larger cylinder. So in principle the smaller the cylinder the thicker the insulation has to be.To avoid losses and to bring you over a shady day as well.If you use efficient evacuated tube colectors then the losses don't matter that much since tube collectors will produce usable heat on darker days as well. But you still might have to face the problem of hot summernights if your cylinder is of the meager type (thin insulation).

bamboozle

thanks for all your replies, Heinblood regarding insulation i was not told what insulation would be on the cylinder all i was told in the quote was 300Lt copper cylinder – dual coil solar'
so should i ask for the insulation on the cylinder to be min 100 mm of PU foam? is this a requst they can agree to easily? as i thought most came nowadays already with insulation on them?

thanks!

heinbloed

You should under all circumstances insist on a detailed offer, stating all materials, quantity, quality and test certificates. Solar collectors have test certificates (estif, solar keymark), check in the estif data base how your collector is scoring compared to others, use the excell data sheet for this purpose. This you'll find in the estif web page.If your installer cares about quality he has that ready available. For solar tanks a testing certificate is under preparation, so ask for a quality assurance of the manufacturer in writing. As far as I know there is already a testing and certification scheme for solar packages(where tank, collector and control station come together). Check the estif home page for exact details of this: http://estif.org/ The insulation thickness of the tank as well as the U-value must be stated, otherwise you risk that you're paying for trash.So has to be the content(volume), the material choice (what type of stainless steel), the pressure resistance and the heatexchanger's efficiency, their food proof quality and what maintenance is required.If your installers can't help with these informations (in writing!) then obviously they don't care what is installed by them.Shop somewhere else.

heinbloed

The demands that solar systems have to meet are regulated in EN12976-1, the adherence to these demands have to be tested according to EN 12976-2.If a tank is manufactured/installed according to client's demands it should comply to ENV 12977-3 .Ask your installer for this.P.S. Yes, you should insist on a 100mm insulation of the tank.

homer911

Just a comment on the thickness of the insulation - super efficient insulation will result in your hot press becoming a cold press! If you or your partner like to air clothes in their, this could be a problem for you.

sydthebeat

homer911 wrote: »

Just a comment on the thickness of the insulation - super efficient insulation will result in your hot press becoming a cold press! If you or your partner like to air clothes in their, this could be a problem for you.

the days of having a 'hot press' to air clothes heated from a cylinder are over. If the hot press is to be used to air clothes it needs its own radiator...

Gtec

Hi,

I have a copper cylinder (210 ltrs) with 40 mm of foam insulation. It is the one aspect of my instalation I am very annoyed I skimped on. There are 2 reasons for this, firstly, the insulation is naff, I have a very HOT press in the summer (whatever that is;-() and the water temperature drops rapidly in the tank at night (I know this because I have a datalogger attached to the system and have graphed the temperatures), the sendon issue is that my copper cylinder is only rated for gravity fed systems, I am considering re-doing my bathrooms and kitchen over the next few years, and would like to go to a presurised water system, which would mean changing the tank.

Also I spend nearly €400 on copper pipe and brass fittings for my system, I should have gone with the stainless steel pipe in retrospect as it would have been cheaper and easier to install.

If you want to see the graphs of the sytem performance on my system PM me and I'll send you the web link (can't post it as it is on a commercial site)

heinbloed

Hi Gtec!It might be worth it to try getting a better tank installed by the original installer. Solarsystems have to meet certain min. criteria. If you have received a subsidy from the state or a state's body for your solar system then your tank's insulation should be more then 40mm.Check that out with the SEI.And put some pressure on the installer, not on the tank (smiley).

homer911

homer911 wrote: »

Just a comment on the thickness of the insulation - super efficient insulation will result in your hot press becoming a cold press! If you or your partner like to air clothes in their, this could be a problem for you.

Yes, we've found that to be partually true, the "hot press" is at about 25-8C in the winter. We have a 300Litre thermal store, most of the heat comes from the connecting pipework, one or small sections not fully insulated plus the UFH manifolds.

The heat is redistibuted via the MHRV as well.

nmacc

It's worth considering a stainless cylinder if you might ever change to a pressurised system, as (most) copper cylinders cannot be pressurised. However I must take issue with one thing Heinbloed wrote, reluctant as I am to contradict him.

"if you use stainless steel pipes then the copper will be attacked by the "better" metal, make sure you use stainless steel or glass in the collectors as well. Otherwise you would have to use a rust inhibitor or an anode"

Copper is higher up the EMF series than both Iron and Chromium, hence the stainless steel will be eaten away by electrolytic corrosion, not the copper. For this reason it is advisable to fit an anode to a mixed-metal system. I've seen anodes pitted in stainless cylinders after only a couple of weeks of operation.

However that doesn't mean that your stainless will perforate easily, as there was a copper shortage in the 1970's which resulted in quite a bit of stainless pipe being used at that time, even though it's a pig to work and blunts pipe cutters in no time. I've stripped out several of these systems and, having checked them carefully, found no evidence of erosion of the steel or the copper despite 30+ years of service. Include an anode (some immersions already have them) and you should be fine unless you've got particularly aggressive water.

Musha

bamboozle wrote: »

got a list of the following optional 'extras' from the supplier, can anyone advise which are necessary/advisable?

400L Triple Coil stainless steel cylinder (instead of a 300L copper tank, price difference of 800)
Solar Roof bolts
DN 16 Stainless steel Pipe 15m
Fittings for ss pipe
22mm - 3/4" DN16 to panel
Immersion heater for cylinder

thanks

Hi Bamboozle,

Just read your post and am confused as too what you are getting for your money,
Solar roof bolts should be used as best practice as they have a rubber seal to prevent leaks through the roof,
What piping are they going to use if not s/s flexi pipe?
Immersion should also be fit as standard to boost the water to over 60 degrees once a day.

when we were installing Solar we used all of these as standard not optional extras
Would recommend solar DHW system to anyone but I would be concerned with optional extra charges for components that are best practice.

saibhne

Hi Bamboozle, it's unclear as to whether the supplier is also the installer of the system. A supplier of solar equipment may quote for options to the person installing the system to give them choices when determining the details of the installation. They will need to make decisions on the likes of:

cylinder type - could be copper or stainless steel, Single/Dual/Triple coil, differing volumes.

roof mounting options - depending on the roof type this can vary - solar bolts are not always the best option as mentioned earlier as certain roofs such as corrugated steel or natural slate can suit a strap or bracket method better. They can also be more expensive.

Pipework - Flexible stainless steel pipe is a time saving item favoured by many installers but when time is taken out of the equation it can be more costly than using copper pipe with manually attached insulation. Whether to use this would depend on who was installing it and how they value their time. The fittings are related to whether stainless steel pipe is used, if not then they would be superflous so they are indeed optional.

Immersion: Many cylinders come supplied without electric immersions. A 400L triple coil stainless steel cylinder sounds like it may be a custom built item so is likely not to have one included as standard - the supplier is giving this as an option as well but they are easily available from hardware outlets and maybe at a better price. The requirement for legionaires protection is to boost the water of the entire cylinder to 60 degrees once a week not once a day. This can also be achieved by other heating methods such as using your central heating so an immersion is not completely necessary, it would also need to be located at the bottom of the cylinder if it is being installed for this purpose, 99% of immersions would not be installed in this position so are incapable of protecting completely against legionnaires.

bamboozle

Just to confirm the supplier is not the installer of the system!

saibhne

Hi Bamboozle,
If the supplier is not the installer I would run the item list by the installer to confirm which items he will require, then go back to the supplier with your final materials list.

Carlow52

saibhne wrote: »

Hi Bamboozle, it's unclear as to whether the supplier is also the installer of the system. A supplier of solar equipment may quote for options to the person installing the system to give them choices when determining the details of the installation. They will need to make decisions on the likes of:

cylinder type - could be copper or stainless steel, Single/Dual/Triple coil, differing volumes.

roof mounting options - depending on the roof type this can vary - solar bolts are not always the best option as mentioned earlier as certain roofs such as corrugated steel or natural slate can suit a strap or bracket method better. They can also be more expensive.

Pipework - Flexible stainless steel pipe is a time saving item favoured by many installers but when time is taken out of the equation it can be more costly than using copper pipe with manually attached insulation. Whether to use this would depend on who was installing it and how they value their time. The fittings are related to whether stainless steel pipe is used, if not then they would be superflous so they are indeed optional.

Immersion: Many cylinders come supplied without electric immersions. A 400L triple coil stainless steel cylinder sounds like it may be a custom built item so is likely not to have one included as standard - the supplier is giving this as an option as well but they are easily available from hardware outlets and maybe at a better price. The requirement for legionaires protection is to boost the water of the entire cylinder to 60 degrees once a week not once a day. This can also be achieved by other heating methods such as using your central heating so an immersion is not completely necessary, it would also need to be located at the bottom of the cylinder if it is being installed for this purpose, 99% of immersions would not be installed in this position so are incapable of protecting completely against legionnaires.

It would be of value to the forum if the requirement in bold could be tied back to an official source.

In relation to the underlined observation I cant say I agree with this: most dual/triple coil systems have the 'backup' or auxiliary heating system [eg gas/oil] connected into the top coil, so as the solar/Heat pump etc 'preheat the water' and the top coil source brings it the rest of the way.

Your proposal would require the top up to be the bottom coil and so u heat the whole tank.

saibhne

Carlow52 wrote: »

It would be of value to the forum if the requirement in bold could be tied back to an official source.

In relation to the underlined observation I cant say I agree with this: most dual/triple coil systems have the 'backup' or auxiliary heating system [eg gas/oil] connected into the top coil, so as the solar/Heat pump etc 'preheat the water' and the top coil source brings it the rest of the way.

Your proposal would require the top up to be the bottom coil and so u heat the whole tank.

Hi there,

When writing above I was going on the information I received on a training course to become a solar installer, since your post I have looked high and low for a definiitive stance on this and can find none - the timing on how often to heat to 60 degrees varies from publication to publication with The most comprehensive source being the CIBSE guide to solar installations which descibed in the vague terms "heat regularly".

The only foolproof way to eliminate legionella it seems is to ensure that all water that comes from your cylinder has being heated to 60 degrees for a few minutes before leaving the cylinder. This means you need to keep the water at the top of your cylinder at 60 degrees constantly. An immersion on a thermostat set to keep the top of the cylinder at 60 would do the job as would bringing on a gas/oil boiler to do the same.

In practice however it is my experience that only lip service is paid to this issue and 99% of solar systems are installed without legionella protection.

As for the use of a boiler coil to bring the whole cylinder up to temperature this can be achieved with the use of a destratification pump plumbed to the top and bottom of the cylinder. When the central heating is on turn on the pump for 20 minutes and move the water from the top of the cylinder to the bottom.

Gtec

if the requirement in bold could be tied back to an official source

I have not read the standards documents on the issue, but the commsioning report for SEI grants on Solar instalations say in section 4.h:
Auxiliary heating set-up to allow raising water temperature above 60 deg. C
regularly to avoid legionella risks

There is also a large body of evidence that the risk of legionella is substantially reduced if copper pipe work is used for water rather than plastic pipe. In fact when i was doing some research on this matter after installing my solar system I found reference to the use of heat in the reduction of legionella risk and if I remeber correctly the requirement was a 30 minute flush through of water at 70 degrees, and all outlets had to be flushed through. That's some variation from the top 18 inches of a cylinder at about 60 degrees once a day! I can't find the reference at the moment.

Gtec

Mellor

nmacc wrote: »

It's worth considering a stainless cylinder if you might ever change to a pressurised system, as (most) copper cylinders cannot be pressurised. However I must take issue with one thing Heinbloed wrote, reluctant as I am to contradict him.

"if you use stainless steel pipes then the copper will be attacked by the "better" metal, make sure you use stainless steel or glass in the collectors as well. Otherwise you would have to use a rust inhibitor or an anode"

Copper is higher up the EMF series than both Iron and Chromium, hence the stainless steel will be eaten away by electrolytic corrosion, not the copper. For this reason it is advisable to fit an anode to a mixed-metal system. I've seen anodes pitted in stainless cylinders after only a couple of weeks of operation.

However that doesn't mean that your stainless will perforate easily, as there was a copper shortage in the 1970's which resulted in quite a bit of stainless pipe being used at that time, even though it's a pig to work and blunts pipe cutters in no time. I've stripped out several of these systems and, having checked them carefully, found no evidence of erosion of the steel or the copper despite 30+ years of service. Include an anode (some immersions already have them) and you should be fine unless you've got particularly aggressive water.

Sorry, but you are completely wrong there.
Firstly its nothing to do with EMF (did you mean electro chemical). Its galvanic reaction, and the galvanic series.
Secondly, copper is above iron, but not chromium, which is marginally above copper. But where copper and iron are means nothing.
Just because they are above or below a metal, there is no relation between them and an alloy of the two. This applies to most properties of alloys.

Stainless stell comes in various forms, each being a different alloy and as such different properties. Stainless steel is in general further up the series than both iron, chromium and copper. Not all of the variants are, in the depends on which it is, steel 430 or 310 for example.

Problems would arise from the wrong thank being used,

copper12

70 to 80 °C (158 to 176 °F): Disinfection range
At 66 °C (151 °F): Legionellae die within 2 minutes
At 60 °C (140 °F): Legionellae die within 32 minutes
At 55 °C (131 °F): Legionellae die within 5 to 6 hours
Above 50 °C (122 °F): They can survive but do not multiply
35 to 46 °C (95 to 115 °F): Ideal growth range
20 to 50 °C (68 to 122 °F): Legionellae growth range
Below 20 °C (68 °F): Legionellae can survive but are dormant
Lets take a step back here lads; your all right; and your all wrong; to a certain extent
If we were to go by the official documents; half the country should be dead
I am not taking legionaries decease lightly; but lets not get carried away
An emersion on timed to operate; lets say once at 70 degrees; can eliminate the treat; cheep and efficient
It is with the solar installations; that slowly heat hot water tanks; that there could potentially be a problem’ an emersion’ would help to eliminate’ any fears for the customer

Carlow52

saibhne wrote: »

Hi there,

When writing above I was going on the information I received on a training course to become a solar installer, since your post I have looked high and low for a definiitive stance on this and can find none - the timing on how often to heat to 60 degrees varies from publication to publication with The most comprehensive source being the CIBSE guide to solar installations which descibed in the vague terms "heat regularly".

The only foolproof way to eliminate legionella it seems is to ensure that all water that comes from your cylinder has being heated to 60 degrees for a few minutes before leaving the cylinder. This means you need to keep the water at the top of your cylinder at 60 degrees constantly. An immersion on a thermostat set to keep the top of the cylinder at 60 would do the job as would bringing on a gas/oil boiler to do the same.

In practice however it is my experience that only lip service is paid to this issue and 99% of solar systems are installed without legionella protection.

As for the use of a boiler coil to bring the whole cylinder up to temperature this can be achieved with the use of a destratification pump plumbed to the top and bottom of the cylinder. When the central heating is on turn on the pump for 20 minutes and move the water from the top of the cylinder to the bottom.

Thanks for reply and the candor thereof.

Just on the de-stratification pump, IMO, not the way to go as the whole idea is to use this fact of nature to your advantage.
see http://www.jenni.ch/index.html?html/English/english.htm

where the tanks are used to collect the summer heat and release during winter: these are 'big boys' can be three storey.

In passing when u did the course did they show aux heat source in bottom coil?

saibhne

Carlow52 wrote: »

In passing when u did the course did they show aux heat source in bottom coil?

No always on the top, bottom coil reserved for solar.

bamboozle

bamboozle wrote: »

got a list of the following optional 'extras' from the supplier, can anyone advise which are necessary/advisable?

400L Triple Coil stainless steel cylinder (instead of a 300L copper tank, price difference of 800)
Solar Roof bolts
DN 16 Stainless steel Pipe 15m
Fittings for ss pipe
22mm - 3/4" DN16 to panel
Immersion heater for cylinder

thanks

Just an update, only got round to ordering solar panels this week, the company involved offered me a further 700 discount, bringing total cost to 2,500 ex vat and this inculdes all materials, roof bolts, immersion heater etc!
very happy indeed with the price!

Sparky78

bamboozle wrote: »

Just an update, only got round to ordering solar panels this week, the company involved offered me a further 700 discount, bringing total cost to 2,500 ex vat and this inculdes all materials, roof bolts, immersion heater etc!
very happy indeed with the price!

Hi Bamboozle,

Am considering solar at the moment. What exactly did you get for that price?
Can you PM me the name.

Thanks

Mark

5h4mr0(k

Sparky78 wrote: »

Hi Bamboozle,

Am considering solar at the moment. What exactly did you get for that price?
Can you PM me the name.

Thanks

Mark

Ditto.

MickLimk

If you want to PM me the details of what you are getting for that price, I can have a look over it to make sure there's nothing missing that you might get hit for later when it comes to install time.

Cheers.

bamboozle

what the 2.5k ex Vat included was;
2*20 Tube Panels
Solar Bolts
22 x 22 mm compression fitting to join panels
259Lt copper cylinder – dual coil solar
Flowcon A Pump Station inc BS3 Controller
Exp. Vess. Con. Kit
Exp vess. 18lt, 130deg, 10bar
High Temp Auto Air Vent
Anti freeze 10lt concentrate
Immersion heater for cylinder
VA 32 Motorised Divert Valve
High Temp Mix Valve
Lightning Arrestor
Solar Roof bolts
DN 16 Stainless steel Pipe 15
Fittings for ss pipe
22mm - 3/4" DN16 to panel

MickLimk

Fairly comprehensive but your installer may still need to supply some materials to complete. Nothing major mind you but all add up! If it were me installing, I'd discuss the following with you:

Flashing of some kind to bring the pipework from the panel into the attic. I've seen a couple of jobs where holes were drilled directly in the slates/tiles, pipes brought through and sealed with mastic, far from a proper job in my opinion. I'd prefer to see pipes brought in properly even if it costs a bit extra.

It looks like you are planning on a heat dump for the summer? Guessing this by the fact that you've purchased a 3-way valve. Don't know exactly what you're planning to use as a heat dump but you will need to factor in some pipework and some HT insulation for said pipework as well as the dump itself (towel rail?).

Again, I'm guessing but is the 3rd last item in your list 15 metres of 2-in-2 insulated DN16 stainless pipe? I'd say it is judging by your total price but if not, then you will need more HT pipe insulation.

You list fittings for the s/steel pipe but when you install a heat dump, there's every chance you may need a few extra. These would include a slightly odd 3/4" BSP 318 (or a made up equivalent) as well as some 3/4" BSP 311's if the diverter valve has female threads instead of suitable DN16 fittings. You will also need another 318 type fitting for the auto air vent. More than likely this will be a couple of fittings together to make up a T-piece that will allow you connect 2x stainless pipes with a 3/8" isolating valve.

Seeing as you're installing a mixing valve (always recommended), my preference is to always run a separate new cold feed from the tank to the cold side of this mixing valve. This helps counteract the reduction in hot water pressure that may result from the installation of a TMV. As a result, you'd need to allow for a run of 3/4" copper and a 350 tank connector.

Other than that, there may be a few other fittings needed when it comes to replace your existing cylinder with the new one. It's rare to be lucky enough that the connections for the existing cylinder will line up with the new one, so there's usually a bit of rework of the existing pipework involved.

Lastly, ensure your your SEI grant form is submitted before you purchase anything. One of the conditions of the grant being approved is that you must have approval before purchasing any components or commencing any work. Best of luck with your install!

bamboozle

Mick, thanks very much for taking the time to provide that thorough response! i'll have plenty of questions to ask the plumber when i see him next!