Marvin

Yup! 5mm gap is enough to squirt foam in! Makes a hell of a difference. All Form. No Function! Yuck!

If the screws are going into the external wall then stainless steel. See if you can squeeze some foam filler in any big gaps. Frame sealant between external wall and external edge of window frame. Inside same but use caulking or what anyone else recommends.

Yes, well, of course, you wouldn't use only hot water either, but worth finding out how much water you are using. My 1400mm high tank can go from 25C at the bottom to 60C at the top.

so in 10 minutes 240 litres of water? Your gonna need a bigger tank...

Yes ASHPs are different and this is one thing I have had to consciously change in behaviour: If the hot water needs heating then heated at the warmest time of the day. House heating and occasionally cooling on 24 hours at low level. Not like my old gas central heating at all!

+1 Is @Fraser Lamont saying he wants to take the middle wall running down the centre of the building away to sort the floor?

My guess would be either an electrical element - immersion heater is on somewhere or the hotter hot tank water is flowing back to the ASHP when the heating is on or, if you have a buffer tank, when starting up the hotter water in the buffer tank returns to the cold ASHP, or the warmer water in the heating pipes enters the ASHP when first turned on, or something else, and all explanations give by other more knowledgeable people than myself! The only way to offer up suitable explanations would be to know when it happens, how long it happens, what is operational when it happens and what the temprature differences are. M

A couple of further questions that will help with understanding the set up... Floor area of the house Volume of the hot water tank Do you have MVHR Do you have PV Are all the pipes fuly lagged? Hot water when on cost alot... how much power was being used? Good luck M

Putting a ridge in the patio seems to me to be complicating things...

I understand the distance is now 5 metres from a building... The regulations state that a rainwater soakaway must be located at least five metres from the wall of a building and at least two and a half metres from a boundary. This is to prevent subsidence of the wall and to stop rainwater on your property from flowing into your neighbour's garden. Check out Labc soakaways. M

The web site pavingexpert.com is an excellent source of information. Do you have details of the type of sandstone being used?

Hi @HJB If the old patio was stable then type 1 on the existing sand seems OK to me. However I would want the old sand compacted before the type 1. I would want to have the grass removed where the patio is to be extended and dig down to the same level as the bottom of the sand used on the existing patio, again assuming old patio was stable, and compact the type 1 bringing it up to the new level. Surely you want the rain water to fall away from your building? So drain run between patio and grass... Good luck Marvin

More of the same... When insulating the ducts I noticed that the top of the MVHR was not insulated so I have installed flexi conduit on the cables ready to throw fluffy over the top. This is the inlet pipe running under the ridge. 150 diameter with insulation held on with cable ties An installed air damper in red. More about these later.... Water coil with thermal lid. Lid made from PIR. Lids off: The coils had no condensation drain so I installed one in the bottom. I cut the bottom 100mm PIR layer so the bottom if the box falls both ways to the corner with the drain and painted the bottom with a protection coat of metal paint. White 22mm drain pipe sticking out with temp cap off. Water trap still to be fitted... Side view of MVHR unit. Note the black "Summer bypass" with the white block on the side

Well that's done my head in....

Can't then vent through side of wall.

Hi @Sandybay Yes the system is 5.12kW max. We had to apply to our Distribution Network Operator (DNO) for permission even though the system will be limited by the CT clamp to a 3kW feed into the grid because the system has the ability to produce over 5kW. we are still waiting for permission. The DNO advised that a decision may take 3 months!!! CT clamp. Yes this irritated me for a while. As I understand it, a Current Transformer (CT) clamp, can measure the current (wattage) flowing through the cable it is attached to. In this set up it will measure the current passing along the cable in between the consumer unit and the main electric meter. As the AC power goes through the cable the coil in the CT clamp produces DC power. The power runs along the CT clamps cable to the inverter. The inverter can work out how much power is being sent into the grid. When more power is potentially able to go into the grid than the level set the inverter restricts the power output. When using the inverter it works out which way the current is flowing; otherwise it would register the current coming from the grid, however some other devices don't and the CT clamp need to go the right way. Good luck Marvin

Typically: Galvanised Truss Clip 47 x 110mm toolstation, screwfix etc... about 50p each. Good luck Marvin

I'm sure someone here has. I unfortunately just did a bit of renovation..... so this is just a bit of a prompt.

Not impressed with all the fixings through the roofing felt either. ☹️

If this was my work I would be fixing metal plates on each one. The ones I would personally use:

is the gable end of the building the footpath boundary?

The viewpoint used to decide items is a balance between the outlay cost and the running costs. This system will not be the cheapest way to produce heating and hot water nor the most expensive installation system but a balance related to the existing equipment and personal requirements. BEST ADVICE: Read the manual of the product you are proposing to use BEFORE you buy, especially regarding the installation and check that it will work for you. Choosing the ASHP: The size of the ASHP was determined by the heat loss calculated and the peak heat demand when the outside temperature is -8C. This resulted in the requirement of a small ASHP. We did not want an all singing all dancing system, but one that would combine with the existing central heating radiators/hot water tank and MVHR. An air to water ASHP was chosen to be able to use the existing central heating radiators already installed. The radiators are too small to produce enough heat at the lower running temperature of an ASHP so water coils are being installed in the MVHR system. The other alternative would have been to replace the radiators with larger ones as the existing ones are almost all single panel which could be replaced with double panel to increase the heat output. This option is going to be held in reserve depending on the effectiveness of the water coils in the MVHR ducts. The ASHP was chosen for it minimum working temperature of -20C and the fact that it had an inverter. An inverter heat pump uses a variable speed compressor which modulates its output increasing or decreasing its speed to match exactly the heat demand requirements of the building as the outdoor air temperature changes. This makes for a more efficient output. Because the bungalow is on the edge of an estate we wanted have a low noise unit. The unit installed is listed as 46 and 60db. I think that means 46db when running at lowest and 60db when flat out. (I'm sure someone will tell me). With the distance from walls and other properties this is well within MCS requirements. Because the bungalow suffered from strong solar gain in the summer the choice was made to install an ASHP with cooling. ASHP - planning, MCS: In order to avoid requiring planning permission the decision was taken to install the ASHP under the permitted development rules. The only position where the ASHP unit could be situated within the rules was on the flat roof. Because the flat roof has 200mm of PIR and the ASHP unit is about 88kgs concern has been raised that the vibrating motion may erode the PIR over time. The decision was taken to install and monitor the out come. The positioning gives an open run of air to the unit, but far enough from neighbours to hopefully avoid problems. Its. not perfect because during the summer it is exposed to the full sun. We hope to mitigate this when cooling the building by using the PV energy to run the ASHP. The theory being: Summer=hotter sun=more electricity produced= more power to produce cooling using the ASHP. ASHP pipework: The shorter the pipework between the ASHP and the thermal envelope of the building the more efficient. The greater the pipe insulation the more efficient. The shorter the pipework between the ASHP and the hot water tank/ heating system the more efficient, especially to/from the hot water tank as the water temperature is usually higher. ASHP connections: The pipework required is 28mm for this ASHP all the way round through the hot water tank, through the buffer tank and back to the ASHP. We used 25mm thick insulation. Two flexi hoses were used at the ASHP end with two 28mm isolating valves. The power cable used was 6mm twin and earth. The cable size is related to the possible voltage loss not just the power required! Apparently the ASHP is sensitive to voltage loss. To be honest I think 4mm could have been used but there was a roll of 6mm purchased for the PV with enough excess, so this was used. A suitable fuse was required which needed to be a MCB or RCBO Type C 20amp with this ASHP. A RCBO was installed. The control of the ASHP is via a Carel LCD "user-friendly" interface Controller and various electrical links. (More later as this develops...) The 3 port valve is a 3 Port Diverter Valve not a 3 port mid-position valve. The mid-position would allow water from the ASHP to go both to hot water and heating at the same time. However the temperature of the water flowing to heat the hot water tank is expected to be different to the temperature of the water flowing to the heating/cooling. The water side of the system will require antifreeze. so the volume of the water will need to be calculated... Please let me know what else I have forgotten...

Installing coil in ducting Note that the condensation pipe still to be connected.

The coils being prepared for the MVHR ducting

An Excel spread sheet has been used to calculate the heating and cooling. One thing also calculated is that at peak energy the bungalow requires as much for the heating in the winter as for the cooling in the summer! So the hottest part of the hottest day and the coldest part of the coldest night need about the same amount of power! This is mainly because of the solar gain through the windows. The calculations were compared with what has been used for heating and it is reasonable good. The calculated heat requirement is down to -8C although I cannot find records here of colder than -5C. It is assumed that the ASHP will supply all heating and hot water when required. (hopefully mainly hot water heating from excess PV power) There is a back up immersion in the buffer tank but I hope to never use it. The cooling is another thing all together. The ASHP manufacturer informed us that if you run the cooling through the radiators below about 19C this will cause condensation - They were right. When running the ASHP in the summer in cooling mode at 18C the radiators began to get wet because the warm air was being cooled and the cooler air could not hold as much moisture.( the buffer tank also started to do the same and this has to be sorted as well) This is what is know as the dew point! Water coils are now designed to be added to the MVHR ducts to overcome this problem by cooling the air entering the building. The MVHR will be boosted with cooling to the east end of the building, or the west end of the building ( no south windows) when there is strong solar gain. As a trial the ASHP will be left on 24 hrs to see the effects. The temperature of the heating water produced by the ASHP will be turned down to the lowest setting which keeps the desired room temperature. Anything else let me know