Stones

There was something on the local radio last week about this. In short, the way the payment has been set up (for speed of payment rather than accuracy) they are using simplified data to determine areas that are not connected to the gas grid, and therefore alternatively fuelled.

To clarify, there is no intention to charge the domestic properties for any excess diverted from the commercial array. Clearly there would have to be legal agreement on who was responsible for the battery and tech that would enable this. In this case it would be the community company that runs the commercial business, as they would also be the landlord of the rented houses. Absolutely take the point if trying to sell to households for the reasons you have listed.

I'm involved with a local project that will be a mix of community commercial premises and housing for rent. One of the things we are thinking about is a semi combined / community PV and battery storage system - fitting as much PV as we can to the commercial buildings, and cascading surplus generation first to battery storage for the commercial buildings, then when they are charged, to batteries in the rental houses. The rental houses would have their own PV fitted, which would divert excess generation into a household battery and potentially a DHW cylinder. Each property, be it the commercial buildings, or the domestic properties would need to remain islands for billing purposes. Is this possible? - I can't see why not Would the domestic properties need two batteries - one for excess feed from the commercial building, and one fed from their own array? Has anyone experience of setting up or been involved in anything like this?

Is it just that window, or every window that you have condensation inside (when outside temp is as per you describe)?

@Barryscotland A friend has something similar to the set up you're describing. TV seems unnaturally high on the wall to me but that's something you can perhaps get used to. What they do have is a 150mm deep timber mantel over the stove position with a steel heat shield fixed to the underside.

Just checked mine, over the last two weeks the ASHP has used 105 kWh on heating (155sqm internal footprint, 50% full vaulted ceilings with an additional 15sqm attic type room - footprint is laid out as two interlinked cottages, so a lot of exposed exterior wall). This has delivered 387 kWh of heat to the house (so a CoP of 3.6). I have the master thermostat set to 19C - we are trying a lower set point this year to see what the energy saving is compared to previous set point of 21C. So far, so comfortable and the house sits around 19.5 - 20C. It can get higher, but that depends on the sun appearing. Ambient temp wise, not as cold here as elsewhere, but higher wind speeds, which ultimately have much the same effect in determining our heating requirement.

We have oak veneered MDF forming our window cills (trimmed with solid oak), and used for all the shelving (visible and within wardrobes), treated with 2 coats of Osmo Polyx Oil. 5 years in, no issues at all. Robust enough for day to day living and doesn't mark moving things around - generally books, ornaments etc. Should be fine on a wall.

@TerryE Really interesting Terry. I've been collected limited data for our build and have 5 years worth. Our heating input requirement, sits between 6500 and 7000 kWh per annum, so very close to you. We solely provide this via UFH, the heat source being our ASHP. Input energy required sits between 1850 and 2000 kWh per annum, the variation being down to difference year to year in weather. Our domestic electricity use (everything other than heating and hot water via the ASHP sits at 4000 kWh annually, albeit I can already see this reducing now our children are away and games consoles are not being played all evening). Our heating requirement is a little higher than I modelled, but not significantly so, and given the year to year variation in heating requirement, perhaps margin of error territory. We have up until now run our house with the master thermostat set to 21C, although in reality the house sits at 21.5C As an experiment, I've reduced the temp down to 19C to see how we get on and whether we are comfortable through winter. So far so good, and it's certainly very comfortable when you wear a jumper. Early indications indicate this change would halve our heating requirement.

I run my house as a single zone, using the FTC controller as the thermostat. The bedroom.have there own but they only open and close the individual loops in the UFH, they do not call on the ASHP for heat.

You'll have massive overshoot of internal temperatures at 45C flow temp. We are in an ICF build, and flow temps generally run between 30 and 35C. We also have a Mitsubishi Ecodan 8.5 kW with FTC5 controller, set at 21C target temp through winter. Personally, I'd use the auto function and target temperature on the controller and let it sort itself out.

Yes, vertically mounted, and can only assume when it failed there was as you suggest, a flame. None of the wires attached to the various pins had any damage (other than a couple with a little soot on the connector). What is the likelihood of it happening again - not sure. Given the relay that failed only costs a few pounds, it may very well. Hopefully with a completely new control module/ board the risk of repeat is less. In terms of fire, given there would appear to have been a small flame, I'm not sure what to think. The control board itself is.mounted on the back of the main body of the oven, and then covered by a metal panel, so in effect sits in a metal box.

Definitely a hole in the side of the relay:

Yes, replaced the board. Marital harmony demanded a prompt resolution. My question was really whether it was worth having a go at repair of the damaged board. It's 30+ years since I did any meaningful electronics so I'm a bit rusty.

The culprit! @ProDave - is this repairable / worth trying? Control module replaced and all working.

Any scope for crane and concrete skip / hopper, or telehandler fitted with pouring bucket?

If they had any sense, said generators could get out ahead of this by committing a healthy % of any excess to supplement existing support mechanisms and commit to additional generation investment, whilst still retaining some of the additional returns for their shareholders. I see Norway is now talking about below market price agreements, presumably sensing what Germany the EU will eventually get around to imposing.

Agree that this would be a far better approach. The only snag then becomes how to address the disparity that will arise for those who do not use / have access to gas. Fairly easy to address given utility companies know who has gas and who does not.

We have an 8.5kW Mitsubishi Ecodan, FTC5 controller and 300l pre-plumb cylinder package. It has been running 5 years, and consistently returning CoP of 2.5 - 2.6 for DHW, and 3.6 - 3.7 for Heating. The DHW temp is set to 50C. With a 300 litre tank we do not run out of hot water. Tank size was a specific requirement and not the normal match for the heat pump size. I knew from experience that a 200 litre tank was too small. As has been suggested, reduce the temperature the DHW is being heated to, 1 C at a time. You should also (if you have not already) select the Eco DHW function - this heats the DHW more slowly but improves your CoP by around 10%. On heating, our system is set to auto weather compensation. I have had to do nothing more that. We run our house (155sq m floor / UFH) as a single zone (albeit we do have thermostats in the bedrooms should we wish to isolate them) using the master controller / thermostat as the control mechanism - i.e. temperature set at the master controller. I strongly suspect from what you have described is that there is insufficient volume of water in the heating circuit when you have differentials set in the house, and consequently the heat pump is short cycling and never getting to its most efficient. The easy way to test this theory is to open everything up, set the heating to 21, and see what happens. If as I suspect, you see a big improvement in your CoP, you then have a choice. Operate as a single zone, or install a buffer to provide additional system volume so you can operate multiple temperature zones. A quick example - a friend of mine has the same heat pump and control, yet his heating CoP was only a little over 1. He has a small area of UFH and the rest large radiators. He had all the radiators throttled back and consequently the heat pump was constantly trying to maintain the set temp through a limited area (and volume) of UFH. By simply opening up the radiators to full, we doubled the CoP to over 2. Not great but vastly improved. In his case it will get better again as he has another 40 sq m of UFH to add to the system in his final phase of renovations. The point of the example really is to stress the need for the system volume to meet or exceed the minimum requirements of the heat pump. If you go below that, you will get significant short cycling and poor performance.

Phoned up BSH to request a remote diagnostic, to be told, we don't do that (even though their website says they do). However, the advice I did get based on description of fault was that it was either the element or control module. Worth throwing the dice on a new element first, being considerably less expensive than the control module?

I had it open today swapping out the PTC sensor and temperature limiter, so I don't have an issue opening it up. It's a relatively quick job to get to the module so easy enough to try (can't help but think of the 2x2 shaped dent in the solenoid of my first car which required the occasional 'tap') Phoned Siemens today, and should be able to get a remote diagnostic check tomorrow as its WiFi enabled.

When you switch the oven on, you select the heat type (function) and set temp via digital display screen. You then have to press a physical 'start' button to activate the function. If you do not press start, then the element does not come on.

Just tested the top/bottom heating function - as well as the top element, the main element came on, red hot, pushing well beyond set temperature. Control module are available, sadly they cost £166

I currently have the following oven: Siemens HB676GBS6B/13. It is five years old. Last week, it overheated, an alarm message eventually showing saying the appliance was too hot. The main 2200W element was glowing red hot. The temperature control showed the oven heating, but for some reason failed to maintain the set temperature, i.e. the element stayed on and kept heating the oven. I've just replaced the PTC sensor, and temperature limiter, but on testing, the problem remains - the oven is not regulating temperature (main element). Looking at the spare parts exploded view: https://www.siemens-home.bsh-group.com/uk/supportdetail/product/HB676GBS6B/13#/Tabs=section-spareparts/Togglebox=tb0420/ The only other things that I can think of changing are the element itself, and the control module. Given the element is working, and in of itself, appears dumb / nothing more than an element, the control module (£166) seems the only realistic answer. I will be testing whether the oven functions normally just using top and bottom element heating later today (once it has cooled down from the earlier test). Any thoughts or other suggestions.

I've read a few reports of Gas producers ending long term (low price) supply contracts by paying the break fee, as the current price means it's worthwhile doing so. Is there a risk electricity generators could do the same?

The amount of political haymaking at present is unbearable, and none of them seem willing to talk about demand reduction. What I think it would be useful to hear openly discussed: Removing VAT from domestic and business gas and electricity Increasing warms home discount - targeting help where most needed Energy reduction program in all public buildings - turn down the heating to 18 or 19C and encourage all businesses to follow - stress the green benefits of this approach. Pass an emergency law if need be and enforce. Really push messaging on turning down thermostats and wearing a jumper (and be willing to accept the political flak for saying it) Graduated pricing structure for electricity and gas to encourage demand reduction, the first 2000 is the cheapest, followed by the next 2000 and so on. Get all the fixed priced generators around the table and impress on them (especially those who receive or have received subsidy payments in the past) that they need to divert a significant % of the current excess profits back into supporting those needing help - if they decline, move to compel / impose emergency levy to boost warm homes discount. Urgently look into whether we can use some of the lower calorific value gas not currently extracted from the north sea