Solar Hot water overheating

[martin ryder]

Had my solar hot water system installed by Smart Energy a couple of year ago. Unfortunately they have gone bust and have no recall. It turns out many solar hot water companies had reported problems with their installs.

My problem is my system keeps overheating and blows the PRV's located on the roof. Therefore I plan to fit heat dumps in the form of a radiator in the bathroom. I have 20 tubes 2 pumps on the pump station and and 130 L vented cylinder. There is no automatic air vents. I really don't want to get another cylinder due to costs.

Can anyone please advise if this is feasible and if this would work and where is the best place to tee off on the flow and return.

Many thanks

 

[Toddyplumb]

Is it actually overheating or has the expansion vessel failed/lost its charge ?

 

[martin ryder]

I checked the expansion vessel and its 1.2 bar I presume this is OK as 1.2 is written in marker pen by the installer

 

[Toddyplumb]

How did you check it ?

 

[martin ryder]

With a footpump

 

[Toddyplumb]

Was it disconnected from the solar circuit ? I presume you mean you used the guage on the footpump

 

[martin ryder]

Yes, sorry the gauge from the footpump 1.2bar. The solar curcuit is still live but the pressure gauge at the pump station is zero.

 

[Toddyplumb]

Right. Yes you can fit a heat sink . If I were you I would contact a local firm qualified in solar installation and get there opinion first, I would hazard a guess that the cylinder is undersized.
Heat sink will need 3 port valve, dual thermostat etc

 

[ecowarm]

I have been called to a lot of Smart Energy systems and have found lots of faults with them, you're lucky it blows of on the roof.

I have seen a few where the Spiro air vent has blown off in the airing cupboard!

 

[martin ryder]

Thanks Guys.

This really is turning in to a money pit. Agree the cylinder is undersized but can't afford a larger one. Can I assume a normal 3 port valve would be OK to cope with the tempeture ?.

 

[ecowarm]

No, you need a solar one

 

[ecowarm]

Just a thought, how are you refilling the system after it looses pressure?

If its with water you may have lost all the glycol

 

[markfxy]

If you're cylinder is under sized why dont you just take a few tubes out simple:yesnod:

 

[martin ryder]

We had it filled by an professional engineer. They charge about £130 each time. (3 times already). This time I'm going to do it myself either with a central heating pressure pump tester (rotherburger) or someone suggested a garden sprayer pump.

Taking out tubes sounds a good idea. Did not know I could do that. Do I have to blank off each tube. Sorry for being clueless.

 

[Furgazoid@hotma]

Ok not big problem, solar thermal is simple! Its a collector a pump, controller and somewhere to put heat, is important to have good flowrate, large solar rated expansion (up to 140 deg celcius 18ltr) What can cause a blowoff;Pump not coming in when should (controller setting)Flowrate cannot be achieved (air or in adequite pipe sizing)Solar array oversised to dhw(tank up to temp so no need for pump to run then overheats then stagnates then blows off

 

[cssolar]

Over heating of vacuum tubes is quite common,
I have found a simple way of de tuning in the summer is to stick some electrical insulation tape on the face of some of the tubes, this can be easily peeled off in the winter

Tony

 

[Nostrum]

Just had a call re; a smart energy install. pump station is leaking, has been repaired a few times and the customer wants a new unit fitted.

Anyone know if a direct replacement unit is available or if it will be a new station and controller and stats etc? Not seen the job but from what they say it is own branded gear, no idea of manufacturer.

Cheers in advance

 

[ecowarm]

Own branded controller usually and rubbish. You will proberbly have to visit first as they are all different set ups. Need to check what pipe they have used, you can usually manage if you have a selection of solar fitting on the van though

 

[Nostrum]

Ok ecowarm cheers, i've not really done much service/repair on solar before, only fitted a couple of systems but not exactly complicated so should be able to sort something out!

It was fitted in 2003 so probably just copper and compression?

 

[ecowarm]

Possibly but I would go and have look

 

[wiggers1]

H2solar shop have pump stations at good prices. Ask for Anthony. They will also have all the fittings you will need on stock.
just to let you guys know, a new solar company has set up in Worksop. They have called themselves Smart Energy. Nothing to do with the other Smart Energy that went bust. They did not know of them.

 

[Nostrum]

oops! I'd consider a re-launch!

Will check out H2solar now, thanks

 

[ecowarm]

H2solar shop have pump stations at good prices. Ask for Anthony. They will also have all the fittings you will need on stock.
just to let you guys know, a new solar company has set up in Worksop. They have called themselves Smart Energy. Nothing to do with the other Smart Energy that went bust. They did not know of them.

They are going to get a lot of irate customer calling, may have to change name
And also agree about H2Solar very nice people to deal with

 

[Nostrum]

Been around to have a look, pumping station is an unknown brand. Pipework is Flexi DN16, leaking from the fibre washers in numerous places. Vented cylinder with draw off dropping 10" before teeing off for the vent, nice.

Are these standard fibre washers or am I going to struggle to find suitable sizes? Will need draining and recharging, are there any compatibility issues with fluid? Only installed new systems up until now and fluid has been supplied by manufacturer, any difference in the various fluids available?

 

[ecowarm]

Give H2Solar a call, Anthony will sort you out, everything in stock and if not local can deliver to site or customers house next day.

Fibre washers usually standard imo

 

[eaton]

Yeah h2 solar will provide separate bits like fittings, washers etc, chemicals reasonable too

 

[Nostrum]

cheers eco/eaton just got my trade account sorted with them, carriage is reasonable too considering the fluid is quite heavy.

Is 10ltrs the standard amount, the tub looks the same as what i'm used to but for some reason I thought it was 25 ltrs? it's only 2 x 20 (i think) evacuated tube panels and a few metres of dn16 + coil?

Didn't look where the discharge pipework terminated either, didn't see a vessel anywhere, I've seen them with the PRV fitted on the roof before? I've always run the discharge into the fluid container as per the book.

Cheers for the help

 

[ecowarm]

I need 20+ liters in my pump to be able to use it