scottishjohn

which is why 4gas analaiser do an auto re-calibrate every now and then when left turned on -you can hear the flow pump speed up when it does it

It really quite simple you can only have 100% of anything ,so if there are greater percentages of some gases there must be less of others

you say "suggest" like i,m making it up. i have reported what i have seen on different 4 gas analyisers in multiple locations I've spent 40 years + building and tuning race car engines been fitting stand alones ecus since 1992 building super charged race enignes since Rotrex came to this country in 1998 I know what i,m talking about when it comes to internal combustion engines and what effects their performance and how atmospheric conditions effect dyno results I also have over 300 hours logged flying home builts and other piston engined aircraft ,

it will probably be a local effect of city pollution on the air, alot of the polllutants are heavier than oxygen and probably are displacing it to a higher altitude. I really have no idea -as its something I could not do anything about ,so pointless to think to much about it with what i was doing ,enough other variables to contend with when tuning performance engines or fitting total stand alone ecu systems. so yes all modern ecus systems use air density and air temp to adjust fuelling to get best performance/emission control ,they do this in real time and also when you stop It will make adjustments to base ecu map adding the corrections it has had to make while you were running ,so when you start it will work from the last base map + that days corrections example --you are in south africa at coast then drive to up table top mountain and stop -it will recalibrate ecu settings as though that 6000ft was sea level for next time you start up . this is a simplification of what happens every day you drive a modern car . all that whirring noise you sometimes hear after you turned it off is it checking sensors and calibrating them for next start

I,m not talking about air density but the amount of burnable oxygen ,which does effect power i don't really want to start giving you lessons on the internal combustion engine and the ideal air fuel ratio for best power or economy just accept that more oxygen means more of a bang and more power by the fact that you can add more fuel to burn to keep the air fuel ratio correct . on n/a engines max power is usually attained at around 13-1 air fuel mix on a modern 4 valve engine -older 2 valve types could be more like 12-1 I have no experience of jet aircraft only piston engined ones - and max engine performance on a piston aircraft will be at sea level it declines as you go higher due to the thinning of the air --and above 8000ft you will start to see a performance drop , from 5000 ft you normally start to lean off the mixture because of the lack of oxygen in the the thinner air makes it run rich and is neither good for power or the life of the engine temp will also compound this . this is getting way off the topic

no these machines are self calibrating every time you switch them on .has to be accurate for the emission test for the MOT . the oxygen sensor is a part that is changed regularly , if it needs it when the machine is serviced so yes there is that much difference in air quality due to pollution between city and countryside wonder how low it is in inner london !! its not as though i have seen it just the one time but when i was going around tuning cars for other people i would always look,as it also effected the bhp an engine could develop and accounted for some of the variance in test readings from different dyno,s ,that and inlet air temps and amount of wheelspin during the test . air temp would be the biggest factor if dyno was calibrated correctly . raise inlet temp by 10c and you loose 3% of power --by pure physics ,in real world it is always more probably more like 5%--so keeping inlet temps low is always good for power I never got to find an actual figure i could quote for less oxygen in atmosphere not something i could change ,but I know cold day and tested in countryside dyno was always good for big power output

I understand that --but I know SHE will still open the windows for a few hours everyday as she has for the last 50 years since she had here own house and i don,t want to be trying to heat the whole county . I will be allowing for fitting of mvhr in building design ,just in case ..maybe even fit the ducts in tight places same as i would always put a draw cord in a ducting --just in case.makes life so much easier if you alter things later and costs bugger all to do

both towns quoted are virtually sea level as is where i stay so it is a direct comparison

the current trend to go full open plan will not make controlling temp through out the house easy and I Intend to have rooms and dif zones for temp control as I have now . why would i want kitchen same temp 24/7 as living area? -separate kitchen keeps smells where you want them . for that same reason I,m not convinced on MVHR ,as my wife will not stop opening windows to get in fresh air everyday ,how ever i build it Of course we do have fresh clean air up here last time i was in a garage with an mot gas analyser in glasgow and was similar in manchester the Oxygen content of the atmosphere was 18 .2 % here in the country side it is always 20-21% thats a large difference that no MVHR will make up for in your house

I,m suprised the victorians with their love of cast iron didn,t make such a thing or italians --cast a highly polished alluminim one like they do the radiators or even SS to go with the ultra modern designer bathroom simple to tig weld ss piping to back of it

I did think it would be his sort of thing .LOL

In scotland check out isodom 2000 https://econekt.co.uk/ econeckt in glasgow is agent +they are also family building firm as well will supply or anything up to turn key worth a look at least

for those of you who like to wallow for hours in the bath I,m suprised no one seems offers a bath with UFH piping wrapped around it and bonded to the grp +then spray foam on top of it to keep heat going inwards + a temp control to keep bath water up to temp all day long if you wanted my first wife was one of those and I often planned how easy it would be to even as a retro fit . it could also be the bathroom heater /towel rail the rest of the time ?

just as an aside to the problem you see the green stuff on the copper pipes --thats showing the plumber did not clean all the acid flux off after doing the joints In time that could cause corrosion of the copper pipe ,as you already have the tell tale signs probably will not rot pipes right through -- but cleaning all copper pipes very carefully after soldering is highly advised so no active acid flux left behind which is why i have already decided to have no joints anywhere that is boxed in by using a pexi pipe system and manifolds , junctions are in places you can get at them in the future

my present ufh/suspended floor on an old TF house works very similar which got me thinking more about this . Ifeel there is a mid way to get best of both and full use of free suns energy without more technology to harness it

can,t directly agree with that if floor is absorbing heat ,then it will also give it out at same rate as normal and if slab rises to above the temp set -heating will turn off until it goes below that again . the problem I am seeing from what you all write is that floor is up to temp already ,then you get solar gain , so house temp rises and because floor does not change quickly even if it turns off you get the unwanted extra heat absorbed into the floor. If the floor could change quickly then the problem would be lessened . trying to work out how much heat you will get ,so you could turn off the UFH before it gets to target temps,saving energy and letting sun top it up is a very hard thing . air in its self is a very good insulator so your solar gain is coming from the sun heating something solid -- so temp rise is a result of that hard surface letting the heat out again the energy to heat the house will be the same no matter if it comes from a large amount stored in floor or a smaller heat store of thinner floor ,but which then turns on heat source sooner to top it up maybe for you guys with excess PV the sunamp is very good idea so you store the excess energy ready to be used when needed be it for the UFh or DHW using air con to combat this which is costing energy seems wrong in our very changeable Uk climate . fine if canada where they have proper seasons --

yes low voltage and high amperage will still hurt you . when i was young and foolish i was working on a car with a wrist watch and it shorted down on the battery terminal when trying to get to something hidden -- took a few weeks for the skin to grow again as it took a lots of layers off before i could get my hand out and was very painful for a long time . watch kept working .

welcome to my world its always like that on cars --you need to disconnect totaly what you trying to test cos so many other connections you can get a reading that is not coming form what you think it is cos there are so many other connections somewhere you can,t see and splices on wiring s you can,t see or find its just you don't, get dead if you touch wrong thing on car -

one might wonder why they are not using solid single strand wiring in that sort of installation -should not be any vibration to worry about and could be bent to shape and could be clamped . we know the answer --its probably cheaper cos you can ,If i remember correctly, use thinner multi stranded wire for same current load,as current passes along the surface of wire

close enough --not Italian anyway

It may depend on where you live ,,as in scotland there will or maybe will be less thermal gain than in S/E england

Italians never could make good wiring or chrome ask anybody who's had an itialian motor bike or car but notice the contactor is german !!

that will be the cheap and nasty chinese contactor they use .LOL. the fact JS says his a bit bigger says it all--bean counters again I have similar contactors in vehicle ramps and never had one go in 30 years -

I have been reading and following lots of topics and the one that keeps coming back again and again is excesive solar gain and how it causes over heating in near pasiiv houses so my suggestion for discussion is "do we really need such a thick slab to act as a heat store " heating thick floor takes a long time ,the house does not loose heat quickly if is well insulated + then out comes the sun and you need to lower the house temp . why not just a thinner slab so it can change temp quickly how will it be any more expensive just to heat the floor when you need it and so get round the over heating , excessive solar gain onto a floor that is already up to temp must be a waste of energy in first place -use the solar gain , to supplement the floor heating and not cause other problems ,which you may have to use energy to correct dropping floor temp of a large mass will not happen quickly and will again be a waste of energy

would not be first time i have seen these sort of trips hidden --so user don,t know where they are --so they cannot just keep resettting and they have to get it sorted