MJNewton

Apologies; I missed this. As @JohnMo said this was just generic filter material - I bought mine from https://www.justfans.co.uk/synthetic-air-filter-media-10mm-1000mm-1000mm-p-2037.html. I see it is listed as G3 whereas I thought I was buying G4 as per what was originally supplied. Either the page/product has changed or maybe I never was. I'm not too fussed either way as I've been using it for a few years and it seems to be doing the job.

I got them from a Paul Heat Recovery page at this link which, unfortunately, no longer appears to exist. This is a shame as it went into some detail behind multiple methods being useful, and explained it well along the lines of the other info that they still publish. Here are the calculations though: Method A Efficiency = 100 x ( SupplyTemp - IntakeTemp ) / (ExtractTemp - IntakeTemp) Method B Efficiency = 100 x ( ExtractTemp - ExhaustTemp ) / (ExtractTemp - IntakeTemp) Method B attempts to factor in unit insulation loss which can also include heat going into the unit from the surrounding area this artificially boosting the apparent efficiency calculated with Method A. I am probably explaining it badly, and always just used to refer the the explanatory graphic on the page that illustrate the addition heat flow paths that Method A doesn't take account of. Edit: Here's a somewhat similar diagram from a different site that shows the additional heat flow through the insulation: : With these figures, Method A gives 100x(19-5)/20-5)=93% whereas Method B gives 100x(20-8)/(20-5)=80%

We're really fussy about lighting and are often disappointed with what options are available. For our island we wanted a visible filament, good colour rendition (>90 CRI with decent R9 performance), ideally ST64 shape (but GLS if necessary) and dim-to-warm functionality as it is in a 'family room' that really does needs different lighting at different times of day/use. A lot of boxes to tick and I found a grand total of one option and that was the Philips Master Value series: (shown here at quite a low level hence more towards the 2200K end of the range) They took a bit of effort to drive with a Varilight Pro dimmer as they take a bit of a kick to reliably turn on at very low levels but with some help from Varilight got there in the end. That's a long way of saying 'warm white' in answer to your question, although I would say accurate colour rendition is just as important in a kitchen.

That's good to hear - thanks Simon.

I am renovating/redesigning our utility room and as part of this will need to be rerouting the condensate pipework for the boiler. It is currently piped with a couple of metres of 25mm rigid pipe with a few right-angle solvent-weld bends and terminates into an internal connection to one of the soil pipes. I am considering using flexible pipe for its replacement, such as that offered by McAlpine: Not only would this be quicker and easier for the immediate task in hand but would likely also give greater flexibility (no pun intended) for if/when we move (via replacement) the position of the boiler at a later date. The thought has crossed my mind though: is this sort of pipe something of a bodge, in perhaps the same way that flexible toilet connectors or other waste pipes are commonly considered to be and really only intended for 'problematic' installations (or indeed problematic tradesmen/DIYers!)? I would of course ensure it was well supported and run with a constantly downward trajectory but it's the corrugations and how this would cope with any sediment that might be emitted from the boiler over time that are of concern, along with whatever else I haven't thought of!

Change. Ours came with G4 filters and for their replacement I've just been using a giant roll of cheap generic filter material that I cut and fit into the stock frames. They are certainly always very dirty each time, particularly the incoming filter which is black and full of various insects! The extract is cleaner, but still quite dusty.

Just stumbled across this thread and happened to have been looking at some charts for our MVHR system covering the five years since first installed and thought them worth posting as it looks like performance has remained fairly consistent with no apparent degradation: The overall average efficiency rating of 89% (or 74% using a slightly different calculation method) doesn't seem too bad, particular given the annual drops over the summer as the bypass kicks in an out thus throwing all the figures out. The supply-intake delta (difference in temperature between the outside air and what is being supplied to the rooms) has similarly remained consistent over the years. In terms of maintenance, all I've ever done is replace the heat exchanger filters every 6-12 months. I haven't cleaned any ducts, external grilles, the heat exchanger itself etc.

The cylinder does have a plastic diffuser at the bottom - could it be that breaking up? (I know they are prone to being blocked by limescale but haven't heard anything about them deteriorating though)

We've got a Titon - also bought on ebay as it happens - and have been very pleased with it. Ours is quite a basic model but I've retrofitted various external controls to improve its functionality a bit. Re technical support I was pleasantly surprised to even receive a response to my request for further info about the summer bypass logic, and they also sent a service manual too which I wondered was down to me sounding like 'the type that like to tinker with things'!

It was more in case it ever got damaged, or overrun with scale. I am planning on checking and descaling ours, and I am mindful that removing the immersion heater - which has been in place for 18 years - could lead to damage but hopefully the duplex steel is a lot stronger than copper where perhaps this risk is more likely?

Thought it worth posting back as whilst not the most exciting of subjects you never know if it might help someone else out in the future. As per the discussion I tried nipping up the flange bolts but to no avail - air still leaking out over a matter of days. By chance someone nearby was ripping out their perfectly working identical cylinder due to the installation of a heat pump so I bought the expansion vessel off him, and the cylinder too as these things are always worthwhile having a spare of, right?! With the replacement EV fitted everything is now working properly. So, what was wrong with my old one? Well, I removed the flange plate and pulled out the bladder - the 19th century football appearance immediately pointed the finger towards corrosion being present: Sure enough it was clearly visible inside vessel: And most crucially at a couple of points around the neck too which corresponded to where I'd seen bubbles emerging from once the vessel was out and I could dunk it in a bucket of water: So problem now solved and all that's now left is to work out where best to story the spare cylinder, the acquisition of which means I will almost certainly now never need it! Thanks all for the discussion - really appreciated.

Thanks everyine for pondering this with me, and sharing your thoughts. Will report back once things progress.

The PRedV is actually fixed at 3 bar, its the incoming supply pressure that doesn't seem to go above 2.2 bar - we're in a small town fed by a water tower and we're at the top of a hill too so low pressure is fairly normal around here. Even if the PRedV was passing a higher pressure whilst that might explain the PRV opening we would still have the EV charge air disappearance mystery. Good point about day/night variation though - I must take a look when the opportunity arises. Stopcock has to stay open as the family aren't coming with me (business trip)! I've recharged the EV though, am satisfied that the PRV does work and will safely (and calmly) discharge if required. I might also set the reheat window to a time when my wife can open a hot water tap for a few seconds to relieve any excess pressure - that's what I do now when I discover the PRV dripping and the EV charge gone.

Don't tempt me to do anything before I leave for the week! 😂

That's right - no water coming out at all! I'm just going to swap the EV. £40 seems a worthwhile gamble to fix it, which surely it will!