I thought one or two of you might be interested to know how I got on with the 'Energy Efficiency Course'. (mandatory exam pass before 31/3/6 required to remain CORGI registered).
We had considerable discussion about several contentious issues.
1) The boiler sizing method makes no allowance for the draughtiness of the home and will come up with (IMHO) too small a boiler if the assessment procedures are used without thought.2) Currently there is a massive culture of continuing to fit non-condensing units claiming an exception where non are allowed. Since the replacement of boilers is now notifiable this leads to a problem. However on the CORGI web site for notifying the work (self certified as complying) there are exemption codes to allow you to specify that a regular boiler is compliant. Make of that what you sill.
3) Now this will please you know who - not. We (That is at least three of the students) argued with the tutor when he started to tell us that a 45litre super-fast [1] recovery cylinder could provide continuous hot water enough to supply a 4 bar ST power shower. The guy next to me said he'd just taken one out because it did not work. The tutor said that he often had a fights almost break out over this subject. The arguments became quite heated and caused the boss to come in to reinforce the 'staff' who then made a you-know-who style declaration from the sales brochure.He said half a ton of water at 26.5 litre minute when connected to a 30kW boiler with 35C rise. The cylinder initially at 60C. I carefully wrote down his claim and then come lunch time did calculations showed that this was plainly impossible. I sort of guessed it was over the top but the calculations showed it was not even close.
Afterwards he confided that whilst he agreed with my calculations he wanted to get people thinking about the need to store less HW (with its storage losses). I pointed out that the merits of fast recovery cylinders don't need sales spin...
[1] 1" connection divides into a multiple-10mm microbore indirect coils each of about 6 turns.