Problems with solar heating

Bindweed

We refurbished an old house 4 years ago and installed Solar Panels. We have a huge hot water tank, 300 litres I think and we located it in the attic, because it was too big for any room in the house. The first problem with it was that some part that wasn't blanked off properly blew on a hot day and we got water leaking down through the house. The plumber came and sealed this and explained it was something he should have thought of, his mistake, apologies and sorted now. That was fine. The next issue was that the heat travelled back to the main cold water storage tank located in a higher attic. It got to the point that in hot weather you couldn't take a shower because there was no cold water !! This was put down to a problem with a non-return valve and again this was supposedly sorted. Then early this summer, we turned off our gas heating and had no hot water. Plumber said it was airlocks in the system and came and got the Glycol circulating again. This had happened last year as well. It worked for a little bit and then stopped again. This time he said the Pump Station needed replacement, and he only did this today. He said that this summer was too hot and caused problems with solar panels. This defies logic, as they are used in much hotter countries than here, but when we challenged this we got nowhere. Any ideas??

Any installation should be fit for purpose yours unfortunatly isn't.

I would ring the manufactures of the solar system and ask them for recommendations of a good installer for a independent report to identify any installation errors if any;).

Once you know what flavour of silliness your dealing with then you can determine the appropriate action/response.

ptogher14

OP I'm not a plumber but sounds like he plumbed the blow off back to your water tank. A cylinder will have a blow off so in the event of too much pressure building up lets it off. In your case this should be plumbed to a drain.

ptogher14

ptogher14 wrote: »

OP I'm not a plumber but sounds like he plumbed the blow off back to your water tank. A cylinder will have a blow off so in the event of too much pressure building up lets it off. In your case this should be plumbed to a drain.

Not if it's open vented;)

ptogher14

I'll take your word. I was just talking a stab at it

ptogher14

ptogher14 wrote: »

I'll take your word. I was just talking a stab at it

And you'd be spot on if it was unvented:)

ptogher14

When you say open vented what do you mean

ptogher14

ptogher14 wrote: »

When you say open vented what do you mean

Open to atmosphere, it's tank fed.

If it were a unvented cylinder it would be mains fed or pump fed from a break tank, pressure would then be a factor.

ptogher14

When you say open vented what do you mean

ptogher14

ptogher14 wrote: »

When you say open vented what do you mean

http://www.glowinstallations.co.uk/hotWater.php

shane0007

The OP's system is most likely open vented. I was called to one this year during the hot spell with the same issue, cwst full of hot water. The problem was the vent pipe was too low, water was heated so hot, it pitched into cwst & a natural gravity circuit was created. Once it started to flow, it continued. Raised the vent & lower the limit of the bottom of the cylinder from the solar resolved the issue.
TBH, it may not be the fault of the solar installer, just a low vent from the cylinder which was probably original to the installation.

Other issues seem to be installer error though.

freddyuk

If the solar has been discovered not to be working twice then my guess would be the gas boiler has been doing all the work and the solar has not been circulating at all and just stagnating.The OP says the cylinder was installed by the plumber with the solar system?? And he got that wrong too. A ruined solar pump if indeed it is ruined would support the theory that the system is stagnating.
Is there a pipe to a container from the solar pump station pressure relief valve? If it exists it is likely to be a plastic container that had the gycol fluid in it. If the system has overheated there may be some fluid in this container but if it is plastic it needs to be replaced.
What temperatures were you getting from the cylinder in the summer?
It is possible the boiler does not know what the solar is doing and is heating a hot cylinder.
The solar controller will tell you what the cylinder temperatures are and if too high the bypass can be set to take the high heat away.... oh there is no by pass!
Also I am not sure where the non return valve comes into it? Where is this fitted?

So go and get yourself a qualified installer and get a by pass installed and take action against the first "plumber". Then the system will run happily all year automatically. I would have the Glycol replaced and the solar system purged whatever.

ccsolar

Bindweed wrote: »

We refurbished an old house 4 years ago and installed Solar Panels. We have a huge hot water tank, 300 litres I think and we located it in the attic, because it was too big for any room in the house. The first problem with it was that some part that wasn't blanked off properly blew on a hot day and we got water leaking down through the house. The plumber came and sealed this and explained it was something he should have thought of, his mistake, apologies and sorted now. That was fine. The next issue was that the heat travelled back to the main cold water storage tank located in a higher attic. It got to the point that in hot weather you couldn't take a shower because there was no cold water !! This was put down to a problem with a non-return valve and again this was supposedly sorted. Then early this summer, we turned off our gas heating and had no hot water. Plumber said it was airlocks in the system and came and got the Glycol circulating again. This had happened last year as well. It worked for a little bit and then stopped again. This time he said the Pump Station needed replacement, and he only did this today. He said that this summer was too hot and caused problems with solar panels. This defies logic, as they are used in much hotter countries than here, but when we challenged this we got nowhere. Any ideas??

Hi Bindweed
(1) The first problem with it was that some part that wasn't blanked off properly blew on a hot day and we got water leaking down through the house. The plumber came and sealed this and explained it was something he should have thought of, his mistake, apologies and sorted now.
You had a pressurised tank fitted on a vented system, this tank is fitted with a P/T Valve (Pressure/Temperature Release valve) when the water in your tank reached 90 degrees from the solar it opened releasing the hot water out into your attic once your plumber blanked this valve that put a stop to this problem but didn't rectify the main problem, your solar system is heating the water too hot in summer.
(2) The next issue was that the heat travelled back to the main cold water storage tank located in a higher attic. It got to the point that in hot weather you couldn't take a shower because there was no cold water !! This was put down to a problem with a non-return valve and again this was supposedly sorted.
I would suspect that the cold inlet to your 300 litre tank is close to the solar coil and the heat generated by the solar is traveling up the cold pipe into the storage tank in the attic heating the cold water, he fitted a non return valve to sort this out OR he could have put a drop down in the cold supply pipe before it enters the tank preventing the heat from rising up the pipe, OR Is there an anti-scald valve fitted??? he could have connected the cold supply to the anti-scald valve without dropping down from the top of the tank and making the connection at the bottom to prevent the Thermosiphoning of your system.
(3) Then early this summer, we turned off our gas heating and had no hot water. Plumber said it was airlocks in the system and came and got the Glycol circulating again. This had happened last year as well. It worked for a little bit and then stopped again.
Your solar system is over heating during the summer months and I would suspect that you have a plastic container some where near the pumping station that has a small amount of Glycol in it from the pressure release valve on the solar or is it piped to a drain and the glycol is been disposed of through the drains
Fit a heat dump and all your problems will be solved as this will continue to happen every summer.
You could also have a leak in your solar system

(4)This time he said the Pump Station needed replacement, and he only did this today. He said that this summer was too hot and caused problems with solar panels. This defies logic, as they are used in much hotter countries than here, but when we challenged this we got nowhere. Any ideas??
The pump was running with no Glycol in the system and eventually burned out , you will need another pump again next year if you dont sort out the other issues.
I would guess that your solar system is over sized and you cannot use all the hot water during the summer months (when its working)
You should have great results from this system in spring/Autumn and winter (yes or no )
I would also suspect that with all the pressure building up within the solar system that you also have a small leak in the system somewhere as when you turned off the gas last spring the solar didnt work , on the side of your pumping station there is a round pressure gauge which should be set at around 2 bar keep a check on this and if it drops to 0 bar then you have a leak.

The good news is that your system is normally working fine but has a few small issues that can be sorted very easy, also I have to give some credit to the plumber, he did make 1 or 2 small errors but has continually returned and tried to sort out the problems even after 4 years, most guys wouldn't answer the phone or would say they are gone out of business.

Fit heat dump, check for leaks and your problem should be solved.

Cc

You pay yer money it should work, it's as simple as that.

The original installer should have excepted his limitations after the first sign that things weren't right and got someone in who knew what they were doing to give him the heads up.

Solar like anything isn't rocket science, if you understand what your doing. There are lots of good solar installers out there, why is it exceptible for a inexperienced installer to have a go at something then spend the next four years learning from his faux pars in someone else's home, let him fit solar in his own loft and suffer the consequences of his bad install until he gets his head around it, then start excepting money to install solar correctly.

randombar

Hi Guys,

Is it common for a solar panel system to airlock every year?

What device would I need to release the airlock myself?

Thanks,
Gary

shane 007

GaryCocs wrote: »

Hi Guys,

Is it common for a solar panel system to airlock every year?

What device would I need to release the airlock myself?

Thanks,
Gary

No it should not.
I would question how the system is being purged.
If the system has a single stream pump station with no built in de-aerator, I would purge for a minimum of 1 hour. Dual stream pump stations can reduce to about 45 minutes.
A proper solar pump station must be used, especially if you have stainless steel corrugated pipework. I would also inspect the pipe runs for sags, etc.

randombar

Thanks for getting back and sorry about the delay.

Not really sure about purging, don't know a lot about the solar panels to be honest.

I have the following pump station.



Unfortunately all pipework is essentially behind plasterboard etc. so don't think I'd be able to check for sags

shane 007

Pump station is dual stream with an air separator.
Issue will most likely be down to purging & will require to be re-purged properly.

ccsolar

GaryCocs wrote: »

Thanks for getting back and sorry about the delay.

Not really sure about purging, don't know a lot about the solar panels to be honest.

I have the following pump station.



Unfortunately all pipework is essentially behind plasterboard etc. so don't think I'd be able to check for sags

Hi
The pressure gauge looks very low, can you check it for pressure?
Should be around 2 bar, you need to check it when the system is cold either late at night or early morning .
It's more than likely that you have had a small leak within the system which has drained the glycol, the remaining pressure is a build up of steam within the pipe work
You need to check all joints for the signs if a weep/leak
Cc

shane 007

Pressure should be calculated to suit the installation. 1 bar + 0.1 bar per meter of head head between the pump station & roof manifold, therefore if the installation is upstairs, pressure would be in the region of 1.2 - 1.3 bar.
Expansion vessel pressure should be set at 0.3 bar below system pressure.

randombar

The photo was taken with everything switched off so that's hopefully why the pressure is gone weird, turned it on on Sat and left it running but the airlock warning has come up.

I'm guessing I'll have to get someone in to do the purging or do you reckon I should go away and buy the gear if I need to do it the odd time?