Dillsue

Agreed. The one I got off ebay works fine. You can see the crimp before you insert the pin into the plastic housing so easy to check it's all secure

Why educate the masses? It's the installers job to understand and set up WC

That's fine if they are plumbers and only tout themselves as pipe fitters. If they see themselves as heating engineers then they are letting themselves and their industry down

What you describe is a classic boiler set up with the boiler starting and stopping under the control of the thermostat. What the man in the street doesn't understand is it would be more efficient and save money to run their boiler under WC. The reason it's more efficient to run WC is that when starting and stopping the boiler looses efficiency so running it under WC makes it run pretty much continuously and makes it run more efficiently. HPs are the same but they loose even more efficiency when starting and stopping than boilers do. You can run a HP under thermostat control but it's almost certainly going to hit the efficiency and running costs

My wife doesn't have a degree and isn't technically minded but got the gist of how the HP works in about 15 mins followed by a couple of questions over the following few days. A couple of those 15 minutes was explaining WC ie the water in the radiators/UFH gets warmer as it gets colder outside and the reverse as it warms up outside. That's all she needs to know about WC and all any householder needs to know.

Might be worth having a trawl through the install manual for your specific model as some features don't appear in the controllers installer menus until switches/links are set in the HP. I'd guess you may not have the ES feature but worth a check if it would be useful to you

Having got our HP up and running a few months ago and switched to WC a week or so ago, I've just had a play with the Energy State feature to see if it can be used to setback overnight running temps, which it can and more besides! On our series 3 model there's 2 wired digital inputs on the control board that can be switched to give 4 differing signals to the HP. This allows you to select 4 differing operating modes 2 of which are fixed, normal and off, with the other 2 modes allowing you to choose from 6 configurable options. These 6 options allow you set back(lower) CH and DHW temps or set forward(increase) temps. I've tested things using a 2 gang lighting switch and all the above works. I've got a 2 channel timer on order so we can switch the digital inputs on a time basis to increase CH flow temp a couple of degrees during our night time cheap period and reduce the flow temp a couple of degrees morning and evening when there's no PV. I've read on the net where some people have boosted CH and DHW temps based on surplus PV so a few options if you can sort out switching a pair of digital inputs. The install manual isn't particularly clear on how to wire the signals and I'd assumed they'd be the same as the thermostat inputs where the HP supplies 240vac that you switch back to a second terminal on the HP via a volt free contact in the thermostat. The ES terminals, TB SG1+2, aren't configured the same!! You have to switch an external 240vac and neutral to each pair of terminals to switch each input!! The terminals are marked L and N.

So long as installers do a reasonable job of heat loss calcs and emmitter sizing, HP manufacturers should have databases of WC settings that I'd have thought should be pretty near. I'm not sure if all HP controllers have this feature but our Therma V has an easily used feature to add or subtract a degree or 5 from the flow target temp which a householder could tweak if the installers settings were a tad out. All a user would need to know is not to be changing that adjustment in more than 1 degree steps and more frequently than every 12/24+ hours. There's a bit to understand about CH scheduling as in how to setback temps if away, understand that it will automatically shutdown as it warms up outside and the change in function of a thermostat as a temp limiter, if there's one fitted. If theyre using a TOU tariff they'd need to know how to get the HP to make best use of that. From a user's perspective I don't think they would need to know more than can be written on a single A4 sheet that the installer can explain in 15mins before they leave. That assumes the installer understands what they've just installed!!

Your average householder shouldn't and likely doesn't need or want to understand COP/WC as that's the installers job. A user only needs to know basic scheduling of CH and DHW which is similar to a gas boiler. The knowledge on this forum is generally no more than a competent installer should have but a layman has no need for.

Quite likely, but best keeping it there til we can use it more cleanly or save it for a rainy day

When evaluating the "technology" do you think your average builder/plumber/householder considers the likely future global cost of dealing with climate change? I suspect the vast majority of builders/plumbers/householders look mainly/only at the £ROI to them and not the likely costs we're all going to pay in the future. Stick a carbon levy on gas boilers and gas usage and people might start making better choices for us all??

Sorry but I got the wrong end of the stick and assumed you were talking about general inverter functions rather than a specific feature.

In your first post you asked "Once I have the grid connected how would I go about setting this up for grid power failure?" That doesnt sound like a plan to me! Whatever you buy make sure it has a G98/G99 cert for legitimate connection to the grid, once it's available. That will ensure your inverter shuts down when there's grid failure. You'd need to work out how to get that inverter running without a grid connection but thats off grid wizardry and probably needs to be part of the plan if you want the PV up and running before you've got a grid connection.

If you've not bought your inverter, dont buy it yet. Wait til you have a plan for a permanent grid tied set up that can temporarily operate off grid. Grid tied and off grid inverters operate differently and you dont want to buy the wrong thing.

Ta. Will have a look

Care to share who your eleccy supplier is?? Those rates look better in all respects than the Octopus Go rates were on!

If there's an administrator at the helm there's a fair chance theyll block anyone leaving if your account is in debit. They may also temporarily block anyone leaving until they've got on top of the companies affairs. Good news is Ofgem will look after your interests if they ultimately go bust and move you automatically to a supplier of last resort(SOLR)which you can leave in fairly short order once any account debit is cleared....we went through 4 suppliers at the end of 2021 when prices went daft. Try and keep your account balance around zero if you can as it can take a little while to get credit back from an administrator. Any account credit is supposed to be transferred to the SOLR but that credit might take a while to get back if you jump ship from the SOLR to another supplier. Don't be afraid of stopping a direct debit if credit is building on your account!

I beleive Renusol do the rails in black.

If you're getting paid 15p to export and can import overnight at half that rate, you likely dont want to use any of your own electric to power things you can schedule overnight such as DHW.

From personal experience that's not entirely the case with our DNO, SPEN Manweb. Increasing PV export capacity a few years ago was agreed in a few days with their engineers followed by a seamless formal G99 application. Similarly in the last few months an LCT application to connect a heat pump and EV charger was reviewed and approved in 2 days with emailed confirmation of approval. Not bad for a big outfit

I see it the other way....the OEM Renusol ones are superior! The OEM ones have deeper "hooks" to engage with the rail yet can still be clipped in mid rail because of the springyness before the bolt is tightened. The depth of the Renusol rail looks to be deeper giving it more strength. The Renusol system will likely be fully tested and certified. There's a reason the eBay seller is using the Renusol name to sell something that isn't Renusol! The bottom line is that you'll likely be expecting your mounting rails to sit on the roof for 20+ years without any maintenance so if you want them to stay there buy the best

Research the Octopus non MCS scheme as it was originally a trial with limited numbers so be sure you can get onto it before finalising plans. Octopus offer the same 15p non SEG export rate whether you're MCS or non MCS but that rate doesn't come with any guarantee of continuation. If you're set on gas CH/DHW then you're going to have alot of spare eleccy. If you get the Octopus 15p rate then I wouldn't bother with an immersion diverter but just let all spare eleccy go to export at 15p/unit and heat your water/charge your EVs overnight on an 8p/unit off peak rate. Before you do anything, check with your DNO what your max export is going to be. No point in having a big array but having to throttle it because you can't export it.

If your concerned about the guarantee the your pretty much going to have to do what Vaillant suggest! That seems to be increase pipe sizes or add a buffer. What does the installer say about Vaillants comments?

When you tighten the screw into the clamp it expands the clamp so it's tight in the rail and immovable. If the screw isn't tightened up the clamps I've used slide OK. They aren't loose in the rails channel but they slide OK. Maybe you've got the screw in to the point it's starting to expand the clamp??

No idea if it's the same on your HP but on our Therma V whether you have an external thermostat or not is set with a DIP switch on the controllers PCB. If ours is set to be using an external thermostat it would need a shorting link(or closed contact from the thermostat) fitting on the thermostat terminals to give a call for heat and get the HP to run. Might be worth checking how your thermostat interface is configured to make sure you've not inadvertently selected it to run under thermostat control when there isn't one. Or just drop a link on the thermostat input. Still puzzling why your flow switch is showing OFF