Marvin

I read on one of the reports that I went through, months back, that the main cause of fires in PV setups in the UK was incorrectly fitted isolators. I assumed it was to do with the box poor fixing choices allowing water in but now I'm not so sure.

After a lot of testing the conclusion is that the pipes out to our radiators which run in the loft heat up and are heating up the buffer tank water. There was no significant loss of temperature in the hot water tank over night and the increase in temperature in the buffer tank was greatly reduced. The radiator pipes are all under at least 300mm of fluffy and thick pipe insulation. This brings me to the problem of the hot roof in summer. I have added another roof vent at the ridge/gable end of the roof to get more airflow. I noted a couple of days ago that the loft was 15C hotter than the air temperature outside. I'm thinking of setting up a fan on the loft end of the vent with a thermostatic relay to come on when over 25C..... Can't see why not.. M

Yes the primary pipes outside the thermal envelope are well insulated. Removing the bleed valve cover. Refilling after removing bleed valve. Valve replaced. However after testing the new valve I found some of the thread joins leaked. I shut everything off to sort this out. I undid the brass fitting a few turns and added 3 miles of PTFE and did them up again. Pressure tested and passed this time. Well the filling is done! Now to test the cooling..

Well I don't know everything, but I think it's because the flap inside the fitting hangs down.

With the anti gravity valve fitted... Now it’s time to refill the system. With the ASHP unit the highest point this means filling from on the flat roof...

I think that is part of the problem because of the large bore of the pipe and the height f the buffer tank above the hot water tank.

Because I had already put in a load of gate valves I only need to drain about half s bucket from the primary circuit. However the straight piece of pipe after the buffer tank valve is only 185mm long. Not a lot of room.... The valve is just about short enough to fit. Minus the ends of the pipe that slot in I need to cut out 100mm but at least 25mm from any fitting. Here we go.... Rough marks Cut one end Making sure that the piece is 100mm as calculated,cut the other end. Pray that it is right because unlike 15mm or to some degree 22mm pipe, 28mm is very unforgiving if you cut the length or angle wrong! Phew!

Depends how far you have to 🚗 to work.

Decided to fit an anti gravity valve.... this will be fun! Must put it in facing the right direction....

Thanks for the replies. I think I will have to do some controlled experiments to find out how long the buffer takes to warm back up after being cooled. Because the buffer tank is subject to being used for cooling it has a minimum of 200mm fluffy around the outside of the buffer tank to avoid the risk of condensation. ( electrics protected). So the rise in the buffer temperature could be happening over a long period of time. Secondly, the emitter secondary circuits run through the loft, and while there is 400mm of fluffy, I wonder if that contributes to the temp changes.

Hi @JohnMo What's the return temp to the heat pump when in DHW heating mode? I will have to test to find out what the temp is. Is the return path heating the buffer as it flows back to the ASHP? That's what I am wondering. M

All stainless steel!

Its that time of year (and getting hotter) when we require both hot water and cooling from our ASHP. Hot water works fine, cooling works fine, however, today the buffer tank was 36C although it had not been heated for weeks. This suggests to me that the heat from the hot water tank is migrating to the buffer tank. This also coincides with my thoughts about what may be happening on cool nights in winter when the bungalow heating doesn't come on over night and the hot water tank seems to lose a lot of its heat. ( it would be reasonable to loose a couple of kW's from the hot water and it be enough to warm the bungalow on a cool night) The primary pipework is all 28mm and very insulated. The primary pipework only goes to the hot water tank and the buffer tank. The emitters are on a secondary circuit circulating through the buffer tank. The 3 port valve only has no mid position, so either supplying the buffer or the hot water, not both. Three port valve working correctly. The top of the ASHP is about 1.4 meters above the top of the buffer tank. The top of the buffer tank is about 0.7 meters above the top of the hot water tank. A circuit of the longest part of the primary pipework is about 11 meters. So, my thoughts are: Can a 900mm long 28 mm copper pipe full of static water carry 2kW of heat from the hot water tank to the buffer tank (noting that the port valve would stop the possibility of the water circulating through the pipe) within 8 hours? If this is not the case what is happening. If this is the case what safe options can I use to stop this. Your thoughts please. Thank you. Marvin

I thought every house in Greece was built passively?

Hi @Ian79 Yes lantern walls needs insulating. Yes fascia area needs insulating. You need to achieve a thermal resistance all around your habital space. If you can find a route where you can go from the inside to the outside without going through the appropriate amount of thermal resistance, that route will become warmer in the summer and colder in the winter. As you say, these will become cold spots and some can cause condensation issues, espically high up areas where warmer and potentially moister air can hit a cold surface. (Have seen this with uninsulated loft hatches) As to what type of insulation, it depends what standard of thermal resistance is supposed to be achieved. Remember that 200mm of wool has about the same resistance as 100mm of rigid PIR. Good luck. M

Hi @Spreadsheetman @Conor has picked up an important point about insulation which hopefully you will only have to buy once and it will not need servicing, it will keep you warmer in the winter and cooler in the summer. @Nickfromwales has commented before on this sort of thing. Sometimes insulating well can avoid having to buy a big / complicated heating system. One of our bedrooms will use about 300w to heat when it's -8C outside. I produce about 70 watts working at the desk so not much left. Good luck M

Hi @horace Further thoughts on the ASHP side: We had an existing bottled gas boiler serving the central heating and hot water system before we installed the ASHP. The ASHP is most efficient when the temperature difference between the outside air and the temperature to be achieved in the water coming out of the ASHP have the smallest difference. This seems odd because you would assume energy in equals energy out but this is not so with an ASHP! With 1kW of power you can produce anywhere between 1.5 and 5 times the heat that you would with a 1kW electric fire. With the above in mind you can see there is a great saving to be made, if you can run the central heating water temperature, as close to the outside temperature as possible. We tested the ASHP setup for our home over the last winter and found for us we are better heating 24 hours a day. We turn down the temp about 3 degrees over night. The outside temperature seems usually coldest just before the dawn so we do not heat the hot water then. However, the lower the temperature of the water in your radiator, the less heat the radiator emits. So to produce the same amount of heat required in any given space, if the radiator usually runs at full blast on a traditional boiler ouput temperature of say 60C, to make an ASHP the most economical you may need a larger radiator. The calculating of the radiator sizes is usually carried out during the heat loss survey. When renovating our home I did not believe that the MVHR would save as much heat in the winter as it actually does and so all our radiators were already 50% bigger than required. Good luck M

there are about 20,000 varieties available Looks like a recent variegated one as the flowers are bigger than the original and bi-coloured.

fusha

Hi @horace To understand these items you can look them up and see if you have them. 1 A tiger loop is a piece of equipment that avoids any air in your oil getting into your boiler burner. A fire valve shuts off the oil to your boiler if the boiler gets too hot (assumes you have a fire) 2 If you don't already have a condensate boiler then you will need to drain the condensation that the new boiler will produce to a drain or a condensate soakaway. 3 Assumes that the connections to the new boiler are not in the same position as the old ones. 4 A magnetic filter collects any iron deposits washing around in the water in the central heating system. As the iron fittings (radiators for example) corrode over time this is collected in the filter. 5 wireless wall thermostatic timed controller that can be controlled manually of via a phone. ( no need to run lots of wires about the house) 6 Two new port valves. used to control the flow of water to the heating, hot water or both. 7 Speaks for itself As they list some items prudent to replace/install whilst having the boiler replaced, I assume that inhibitor will be added to the water to inhibit the corrosion and protect the system and that if the existing water has not been replaced for a long time, that if it is black or has gunge in it the whole system will be flushed through before refilling? IMHO: we converted from a gas boiler to an ASHP and have 5.12kW PV installed. When available we use the PV to heat the house and water, something I could not do with our old gas boiler and you cannot do with an oil boiler unless as @Nickfromwales says you install a special one. 4kW PV will easily give you the majority of your hot water for 6 months of the year, and partially for the other 6 months(simplified explanation), but you would need a 200-300 litre tank and thermostatic valves on the water outlets so you can store enough hot water from a sunny day to hold over for use on a cloudy day/days. So you can relate your home to our position, here are some figures: 100m2 floor timber framed 1970's bungalow on the isle of wight, 2 people. 205 litre tank. ASHP: air to water. Installed are all of the AIM and APE elements: That is Airtightness, Insulation, Mechanical Ventilation with Heat Recovery, and Air Source Heat Pump, Photovoltaics and Electric Vehicle. We have no other sources of energy production at present. Recent results excluding energy used for the EV (metered separately): Recent daily PURCHASED electrical consumption for heating, hot water, lighting, cooking and all electrical equipment: about 4kWh a day. ( longest day 2 days ago) 5 month record 1202kWh ( more in winter) Estimated 12 month outcome 3000kWh Personally we like the ASHP option. Good luck M

Hopefully to percolate, hence not only the possibility of undermining any structure too near, but also requiring an areas of ground to percolate into. A percolation test of the ground would vastly help to evaluate the choices. Solid clay - massive area - quick drain material small area.

Well this is delicate.... When I altered our garage to habitable space I checked with the building inspector.

Insulate the F out of the tank. If you do this you will probably require a digital thermostat to control the heating element and ducting to protect the element electric cable. I used a digital thermometer to switch a 16amp relay. I'm sure others will clarify. I've done the above and the utility room with the tank in is no longer like an oven.

Hi @Onoff I ground the underside of the tiles and sealed the gaps with lead sealant

Hi @Onoff It's unlikely that the vertical frame edges of the solar panels will line up exactly with the joist spacings. To overcome the problem of fixing the brackets to the frames, either install horizontal rails in-between the panels and the brackets, or install noggjns in-between the joists under the roofing felt. M