Pictured above - the frame for the Solar Thermal
Pictured above - the bottom of the ST
frame showing the lower caps that support the tubes.
Pictured above - the old DHWC prior
Pictured above - the Airing Cupboard
after the old DHWC was removed.
Pictured above - our installer fixing
in the last of the Solar Collector Tubes.
Pictured above - a close-up of the bottom of the
Pictured above - the Solar Thermal Tubes in position
as seen from the ground.
The Solar Thermal ("ST" or "Solar Hot
Water") installer turned up a bit later on the first
Wednesday. Unfortunately the Gledhill twin-coil hot
water cylinder wasn't ready yet but the installer was
able to fit everything else. He soon had the tube frame
mounted on the roof. These are mounted differently from
the PV system as they are smaller, lighter and fitted
closer to the roof surface. The PV system is heavier and
mounted a couple of inches off the surface so that
cooling air can flow underneath. PV works better when
cool whilst ST likes to get really hot (of course).
Hence small holes are drilled directly through the roof
tiles and then long screws are screwed directly into the
roof rafters. Rubber washes protect the tiles from
Next came the internal work. A
pumping station is mounted on the attic wall on the
opposite side to the PV Inverter. This all worked out
quite well as electricity and water don't really mix
very well! Thankfully the layout of the house meant that
the garage and consumer board are at the western end
whilst the hot water tank is at the eastern end of the
roof space. There was no vying for limited space - there
was plenty. An expansion tank is mounted on
one rafter. Flexible tubing is laid out between pump and
roof. More tubes go from pump station down under the
loft insulation through to the airing cupboard.
Due to the delay with the Gledhill
tank we had to wait another week before the installer
could come back to finish the job. In that week the
tubes themselves couldn't be put in place so the
scaffolding had to remain in place.
Finally the tank turned up after some
comic comings and goings. It had been delivered to the
installer's head office in Slough rather than our home.
Gledhill had turned up at our home expecting to collect
a cylinder they had never delivered. Apparently the
original cylinder wasn't correct. It didn't have a
sensor pocket for the DHWC temperature sensor for the
KWB Easyfire. The survey should have picked this up but
the surveyor was an electrician not a plumber. He had no
interest in the ST system's requirements and only took a
photo of the Hot Water Cylinder. It really pays to have
a proper survey done by your installer. By 'proper' we
mean thorough! It didn't result in much inconvenience
for us really as the time restriction was on the LCBP
Grant. Since that as related only to the PV installation
then we were perfectly happy to accept a small delay.
The installing company were very good
in bending over backwards to get us all of the right
paperwork so we could complete the grant application.
However we think the old adage is true - "more haste,
After the right tank turned up we
soon found our old domestic hot water cylinder sitting
on the front lawn. The swap over was completed in under
a day so there was no inconvenience of having no hot
water or heating. The water is off for a few hours
obviously but it was of no great inconvenience. You fill
up your bath with water and flush the toilet with a
bucket! If you have a bit of "Blitz spirit" then this is
just part of the fun.
The old hot water cylinder was in a
poor state. It was only fitted by the previous home
owners back in 2003. It was heavy with lime scale as this
is a hard water area and they had no water softener
fitted. We had our water softener fitted after the KWB
went in so this damage is now unlikely. The new cylinder
has a 170 litre capacity. The old one had only a 100 litre
capacity. The lime scale probably accounted for a lot of
that so we easily doubled our hot water capacity. This
now stops us from running out of hot water after a
couple of showers. A really big help around the home!
The only downside was the loss of
space in the airing cupboard. The new cylinder was
taller and thinner. It mean we lost half a shelf.
Later on we managed to reconstruct a partial-shelf from
bits of left-over shelves to give us a bit more storage
space there. Due to the limited width of the tank there is
more space in front of it. You can stack quite a few
shoe boxes there. So we will probably find some small
shelving units that will fit well.
The only significant set back during
the install was the flood of water after the new tank
was connected. This lead to an embarrassing near-panic by
the installer who feared he had not connected something
properly. We quickly ran around the house and put down
some blankets, plastic sheet and buckets to catch the
drips downstairs. Thankfully no damage was done.
The problem was quickly located to
the hole at the top of the cylinder where the Domestic
Hot Water Cylinder normally slots. The installer had decided to use
the immersion heater electrical spur for the Pump Station so he
elected to specify a tank with no immersion heating
element. All well
and good but Gledhill didn't supply the cap to go over
the hole. This would have been quickly rectified if they
had not covered the hole up with a plastic over-wrap
that had been taped in place permanently. Once ripped off
the problem was obvious. The installer popped out to buy
a tank cap and all was then well. However, red-faces all
round and an eternally apologetic installer resulted.
Despite this we felt it was
Gledhill's fault and didn't blame the installer who,
otherwise, did a superb job. It was just unfortunate. We
were lucky that no damage resulted as the problem was
spotted quickly and the water switched off before too
This incident did waste a bit of time but the installer
made up for it and everything then slotted neatly into
place. Soon it was back to the roof to put in the
evacuated tube solar collectors. These do not actually
have any fluids flowing through them that are connected
to the hot water cylinder. The heat transfer glycol
fluid, that takes the heat down to the hot water
cylinder, only flows through the top part of the ST
frame. It extracts the heat from the very top of the
tube. Inside the tube is a long thin element which
absorbs the heat and conducts it to the end of the tube.
This makes the entire assembly easy to install. It is
easy to add or remove the tubes. We were even supplied
with a spare!
Before the installer left he showed us how to operate
the system control panel that is mounted in the airing
cupboard. This delightful box of tricks gives a clear
visual read out of tank temperature. You can set the
desired temperature to whatever you wish. There is also
a "holiday mode" which you can use to prevent the system
over-heating if you are not using the hot water for
several weeks. It all gave us a great feeling of having
a system we were fully in control of.
is a 20 tube ETZ2580 BE Solar System. The tubes are 1.8m
long giving a 1.87m2 aperture.
By the late summer the glycol in the system had vanished
and we had to get BritishEco back to refill and
recommission the system. Various theories were forwarded
on why this happened and we still await a follow-up
visit in 2011 to perform other minor rectifications. We
suspect that the roof sensor doesn't read correctly but
the installer disagrees. They wish to fit a valve to
stop reverse siphoning.
Pictured above - the Solar Pump
Station in the attic
Pictured above - the piping from
Pump Station to Solar Collectors
Pictured above - the top-right-hand
side of the ST frame showing the pipe mounting.
Pictured above - the left hand-side
of the ST frame sowing how close it is to the PV panels
Pictured above - the old cylinder
and the new.
Pictured above - the new cylinder in
the Airing Cupboard.
Pictured above - the Tubes being
Pictured above - the airing cupboard
after all the pipes were re-insulated and the shelves