Photos of my new solar system

youtheman

Here are some photos of my new solar system, comissioned today. All I need now is some sun !!!!

whitelightrider

Was it expensive for the setup and install?

I have the solar tank already, but nothing else, yet. Was hoping prices would have come down a bit.

youtheman

€3500 for complete system, less grant of €1500 so €2000 in total. Tank cost additional €720 plus some plumbing costs which were part of my bathroom upgrade.

ccsolar

Hi Youtheman
You payed €3500 for the panels + €720 for the tank, total €4220.
Is the tank 300ltr? or 200ltr?

CC

youtheman

It's a 300 litre twin coil stainless steel cylinder (make shown on the photo).

quentingargan

Your system will benefit from a bit more insulation around the other pipework coming from the cylinder. In fact, I suspect you will get some gravity flow of heat from pipes in general because they appear to come out of the cylinder and then head uphill without having a long enough horizontal run to prevent gravity.

Basically if you can feel any heat in any of these pipes, you have an issue that needs to be resolved for the system to work efficiently. But your installer should have over-insulated all pipe fittings where they butt up to the cylinder. You can pick up a length of 1.5" or 2" armaflex and put it over both the existing insulation and nuts, and butt it up against the cylinder.

When all is done, you should really have a cold press rather than a hot one.

I can see why you put the panels where they are, but strictly speaking you may need planning. The exemption only applies if the panels are 50cm from any edge of the roof. I woulnd't expect it to be an issue, but mention it in case others see the shot. Also, panels this close to the ridge should probably have an external lightening protection. You may have already done that.

Good on ya, and good luck with it. Hope it serves you well.

youtheman

Quentin, thank you for your feedback. I really appreciate it.

The pipework you refer to was installed by the plumber who did my bathroom upgrade (not my solar installer) My hot press is very small so I got him to make the pipework as tidy as possible (hence the short runs and loads of 'elbows'). I am experiencing some heat transfer to the cold pipes. After a long shower the 'cold' water is tepid. I don't have a non-return-valve on the cold supply to my mixing valve, I thought that may have been the source of the problem. But I'll follow your recommendation and install some additional lagging.

The panels are not as close to the ridge as you think, I don't have the exact measure but I'll check it out.

Once again, thanks for the comments.

sinnerboy

Quentin -

looking at the OP's cylinder stat - do you think it should be moved to the"upper" 1/3 line of the cylinder . Reason - so that the boiler has less work to do to supply DHW during the heating season ?

quentingargan

sinnerboy wrote: »

Quentin -

looking at the OP's cylinder stat - do you think it should be moved to the"upper" 1/3 line of the cylinder . Reason - so that the boiler has less work to do to supply DHW during the heating season ?

The problem with where that stat is located is actually that the coil is a little lower than I would like it to be. The stat is in the middle of the coil.

By raising the stat, you might occasionally get a stratified cylinder which is still holding 100L or so of water, and therefore call for the boiler. The issue with a lot of stainless cylinders is that the boiler coil is so low, that it heats about 200L of water, leaving only 100L for the panel to do that day if the central heating has come on.

In a situation like that, I would be inclined to only let the zoning for the domestic hot water come on at night between 7 adn 9, before bathtime, and not in the morning. Q

youtheman

Folks, I need to query you on a strange 'phenomenon' with my new Solar system (and I hope Quentin has his ears on, 'cause I reckon he has the answer).

I turned on the cold tap and the water was warm. I checked all the cold pipes in my hot press and they were all warm. I went up into the attic and stuck my hand in the 'cold' water header tank and it was warm (and when I say 'warm' I mean it was warm enough for a bath). So heat is obviously be transferred into the 'cold' pipework.

I reckon it can come from two sources:

1. warm water reverse flowing through the cold side of the thermostatic mixer valve. I note from other posts here in this forum that some people recommend fitting a Non Return Valve (NRV) on the cold supply. Considering that my tank was completely full with warm water, I suspect this as the cause.

2. heat transferring through the wall of the pipe itself. I note Quentin's recommendation about fitting additional lagging (which I have procured, am just waiting for some spare time to fit).

Any thoughts or ideas are welcome ?. All feedback gratefully received.

Poor Uncle Tom

Could it be that the header tank is doubling as a dump?

quentingargan

It is hard to diagnose something like this on the web. While I have heard of the thermostatic valve option, this might leak a bit of heat when cold water is being used, but I can't see how that heat would get back up to the header tank in such quantities.

I assume that this system is open vented (fed by the header tank). I wonder if your cylinder overheated during the day? If it boiled into the header tank while you were out and had calmed down by the time you came back that would do it. Do you know what temperature the top of your cylinder got to that day?

You could also check the temperature probes that send temperature info back to the controller. Dip them alternately in icy water and boiling water and make sure that they are reading true. If they were under-reading for some reason, then your cylinder could boil. I must say that I haven't known them to under-read - usually they either work, or they don't.

Check your controller settings that they aren't letting the cylinder get too close to boiling point. 85 degrees is as high as I would go.

You could wait until your cylinder is good and hot, then tie off the ballcock and run the bath so as to completely drain that header tank then fill it with cold water. Then feel which pipes are getting hot between the cylinder and the header tank.

Come back with any more info you have over the coming days. Q

youtheman

Thanks Quentin. Just to answer your queries:

1. it is an open 'vented' system.
2. the controller was installed with a 'default' setting of 65 degrees C for max cylinder temp (top). I recently changed it to 90, but I've just dropped it to 85 on your recommendation.
3. I've two temp sensors on the tank (top and bottom). I've been monitoring them constantly and I can't see any anomaly.
4. yesterday was only a moderately warm day, so I don't believe I over-heated the tank.
5. the hottest the tank got was last weekend (the lovely weekend) when the whole tank got to 75 degrees, top to bottom.

I'll just have to keep and eye on it and try to identify the source of heat transfer. I reckon it will either be the cold feed to the mixer, or the cold feed to the top of the tank (and the overflow to the header tank).

Do I take it you don't recommend an NRV on the cold feed to the mixer ?. I bought one this morning, but I don't think it will work on an unpressurised system (needs quite a lot of pressure to overcome the spring).

Thanks for the input so far. Will keep you informed on my deliberations.

quentingargan

If you put an NRV on the cold feed to the mixer it may produce unpredictable results. There will be higher pressure on the hot side, and this could cause scalding. I wouldn't do it but I'm no expert in that area. Any block or restriction to flow caused by the NRV may render the mixer ineffective. I also don't see how you could get to heat a 40 gallon tank through that route.

I hope you didn't really mean the cold feed to the top of the tank>? If your cold feed is going into the top of your cylinder, that would cause the problem, but somehow I doubt that things are plumbed the wrong way around between the attic and the cylinder or you would never get hot water. Though I have seen some strange things lately...

youtheman

Oops, you're on the ball. The cold water feed is to the bottom of the tank. It was the outlet from the top of the tank (which is connected to the overflow to the header tank) that I referring to. I suppose I can put a rag or something on the end of this line to confirm if I am gettig actually flow to the overflow, or just heat transfer up the fluid.

youtheman

UPDATE

I'm now almost certain that the heat is coming via reverse flow through the cold water feed to the mixer valve.

Water temp was at 55 degrees C (on top of the tank). Some time shortly after prolonged use of the pump/mixer/thermostatic shower I found the cold pipe to the mixer valve very hot. I turned on the shower for a minute and the pipe got cold. Immediately after shutting it down the cold pipe started to get hot again. So I've shut the isolation valve on the cold feed to the mixer.

Now I know the problem, how the hell do I cure it?.

quentingargan

youtheman wrote: »

UPDATE

I'm now almost certain that the heat is coming via reverse flow through the cold water feed to the mixer valve.

Water temp was at 55 degrees C (on top of the tank). Some time shortly after prolonged use of the pump/mixer/thermostatic shower I found the cold pipe to the mixer valve very hot. I turned on the shower for a minute and the pipe got cold. Immediately after shutting it down the cold pipe started to get hot again. So I've shut the isolation valve on the cold feed to the mixer.

Now I know the problem, how the hell do I cure it?.

I'm trying to look again at your pictures. Is the cold feed for the blending valve coming from the cold feed to the cylinder? It should be, but looking at the picture, it is hard to tell.

If there are different pressures on the two feeds to the valve, it would produce unanticipated consequences. Just a thought, but I think you probably need to call the plumber back...

youtheman

The cold feed to the blending valve is a separate independant feed from the cold header tank in the attic. So the hot and cold feeds to the blending valve are operating at the same pressure.

I had the blending valve set at around 55 degrees so that the temperature to the shower would be lowered in two stages, first by the blending valve and then by the thermostatic mixer. So the cold port of the blending valve is open at temps greater than 55 degrees. Following my recent 'problems' I set the blending valve to its max setting (65 degrees). So if the tank temp is lower than 65, the cold port of the mixing valve is closed and there is no risk of reverse flow.

So that's my 'temporary fix'. Not sure how it will work when the temp goes above 65.

quentingargan

youtheman wrote: »

The cold feed to the blending valve is a separate independant feed from the cold header tank in the attic. So the hot and cold feeds to the blending valve are operating at the same pressure.

I can't think why a separate feed would be brought to that valve from the attic. If it is rising to the attic tank from that valve, you may well get siphoning in that direction. I would cut off that supply and feed it from the cold feed into the bottom of the cylinder and see if that sorts the problem. The cold feed to the valve would be downhill, so no siphon effect.

youtheman

Thanks Quentin. I'll modify the piping as you suggest. The cold feed to the cylinder runs the full length of the 'hot press' so I'll tee into it low down and have a 'rising' feed to the mixing valve.