Upgrade to SFB40 complete

[DBeaver]

Thanks to forum members who have wittingly and unwittingly helped with this re-install.

I hope my 4 pictures attach correctly. First effort with piccies.

1st photo shows the 2 x SFB20 panels on my semi. Older panel is shifted to left as viewed. Note the difference in the frame types. I lowered the profile of the older panel, which now sits awkwardly between the wave in the tiles giving the rustic (pi**ed) effect. When set higher it was level, but obtrusive. There is an excessive space between the panels due to relocating the drilled tiles to new homes on the roof. I wasn't going to drill any more! The extra space was useful when loading panel 2 with it's tubes.

On first photo you can make out the insulation "chimney". Inside you can imagine the "inverted sump" air bleed suggested by ericw back in (Air Vent Positioning - Apr 2007).

2nd Photo. Standard 170L Navi twin coil cylinder. I regret not specifying boiler coil location, but the grey insulation on the boiler pipes give a Victorian feel, you think? Solar connections on left. 170L a little undersize for my 40 tubes and usual HW consumption. It went into overheat within 24 hours of commissioning. (Weather was perfect and little draw off).

3rd photo. I've re-installed everything north of the airing cupboard ceiling aiming to reduce the water volume in the solar loop by using 10mm tube. What you see is the recycled pump (40W, 2 speed on LOW) in the north bound leg, a 3 port valve to bring in the heat dump as required, recycled heat dump radiators behind (sizing by DHaslam), heat dump relay box, and pressure vessel. Filling loop, gauge and Pressure Release Valve just out of shot to lower left. Note use of Armaflex tape - easy to use but easy to get carried away at c£25.00 a reel. Only a good pair of kitchen scissors required and Valerie Singleton would be proud (Blue Peter for you youngsters..)

All heat dump connections head south first to minimise any conduction away from the solar loop and latterly I've Armaflexed the first 15" (375mm) too. You might see the blackened 15mm tube - that's what recycled tube looks like when it's been in Armaflex for a year!

I've used isolating valves and added a drain cock to the heat dump so I can drain in depth of winter as an additional frost protection. I won't replace my antifreeze until next winter now.

4th photo. Magic "inverted sump" air bleed. Lower drain cock lets out air collected in the "chimney". I used 8mm pipe inside the 15mm. The upper drain cock allows air out of the south bound leg of the solar loop. (The Non-Return Valve is located close to the tank in the south bound leg). No dragging ladders around and clambering about on the roof to bleed air from this system!

I've suspended 10mm tube in 13/10 Armaflex from a batten using tyraps, but as you saw in photo 3 pvc sink waste clips work pretty well too. It's a fair run of tube from end to end of the two panels. Where the solar loop "pair" come together I've run them together in 13/15 Armaflex.

This re-arrangement has freed up space in the loft. My first rig used 15mm tube for the solar loop and uninsulated 22mm for heat dump. It gave the feel of the inside of a U-Boat!

I've used a minimum of couplers/elbows using bends where possible. 10mm tube can be bent with a nifty hand held bender, but managing 3m of tube at a time in a loft with trusses can be like getting spagetti on a fork.

Instead of reducing couplers I've used reducing sets (22/15mm and 15/10mm) in many places. They're cheaper now if you look around.

My 5th photo (disallowed) would have shown the Resol BS/3 solar controller on the landing wall backing onto the tank cupboard, alongside its fused spur box, the freon filled ancient de-humidifier and new/v.cheap Central Heating controller.

I should have changed out the medieval motorised CH controller years ago. This new job gives all the flexibility to reduce boiler firing to the minute and placed on the landing by the BS/3 gives HW boost and CH advance and all the solar temperatures right there adjacent the bathroom. Motorised timeswitches use a surprising lot of power.

Other work I've done recently includes loft and cavity wall insulation, cheapo magnetic tape/acrylic secondary glazing of the double glazed conservatory and changed out the (one end fed) CH radiator valves for TRVs and in preparation for a boiler changeout. (Ecogen Stirling job if BG ever get it to market!).

I hope this lot of some use to owners of semi detached houses. You don't have to have a Grand Design to make some meaningful energy performance changes.

DB

[Ivan]

I'm interested in the operation of the airbleed - as it's something that I haven't tried out yet (only in my mind and on paper!). Can you give some feedback? which option did you go for - looks like you used a T-piece with a short length of copper pipe pointing skywards.

[DBeaver]

Hi Ivan,

You're right. I used a 15/15/22 Tee on the spigot, a very short length of 15mm copper and a compression stop end. The chimey effect is caused by a stack of Armaflex on top.

One thing to watch for is the length of 8mm running inside. Clearly it needs to go close to the end cap but not bang up to it. First attempt I didn't allow sufficiently for the olive squeezing up with the result I had a near perfect air tight seal between the inner and the end cap. I had 1.4 bar on the gauge and a pitiful dribble coming out of the drain cock. I couldn't believe it (Meldrew..)

Best to assemble the innards with the 8mm overlong, insert it to the stop, measure accurately how much to trim off, add 1mm and bingo. It's best to keep the 8mm straightish too.

As suggested by others it's best fitted at the hot/downstream, end of the manifold where the sensor should be. Overkill to have one both ends.

I suspect the restricted way passing through the tile is a potential freeze point, however because the temp sensor is there the CFR function on the Resol should keep things flowing.

Mine has done 1 years service now. Just refitted it for the re-install.

DB

[Ivan]

I think it was ericw who suggested using a taper-cut at the top end of the 8mm pipe - that way you can push it right up to the endcap and not worry about restricting flow. Seemed like a brainwave to me.

[DBeaver]

That would work well. It would give you more water than you need coming out with the air presumably.

It bleeds out very easily regardless. If your filling loop check valve is within easy reach you can purge it through using mains water. The damping action of the pressure vessel makes it a doddle.

I found the loft a convenient place for my "gubbings". The connections are all close: mains water behind a stop tap, overflow for the prv outlet, electrics closeby as well as proximity to the panel for bleeding out. More space than the airing cupboard too.

DB

[Brandon]

nicely done