Mattg4321

CEF can occasionally be good, but you have to negotiate everything. They are unbeatable on some items. Also, unlike TLC, they are a proper wholesaler and will get you anything. TLC are not really too interested if it’s not on their website. I’d never recommend a member of the general public goes to CEF though!

TLC are good if you have one locally. Quite competitive on most things and their pricing is very transparent- all on the website. I don’t get much of a discount even spending 5 figures there per year as their prices are already quite good. CEF on the other hand…

Should the steels be galvanised if outside the thermal envelope?? My SE insisted on it with a couple, but not sure if entirely necessary, but seemed like a sensible idea.

It’s the Vent Axia Sentinel FH. I’m starting to wish I’d gone for the Zehnder Comfoair though, which was also a contender. Size and cost swayed me towards the Vent Axia, which many on here seem to be happy with. Thanks for your help @Mike and everyone else. Looking at the figures, these comfowell manifold attenuators seem to perform significantly better than almost any pipework silencer than I can find, and it should be a relatively straightforward job to swap it out, so that’s what I’ll be doing asap when I’m back. Will update in due course.

Looked into this more thoroughly. I had thought you needed to be buy the manifold and also the attenuator, as well as both end plates (1x160 and 10x75). It appears I’d only need the attenuator and the end plates, which makes the cost slightly more palatable. Looking at the data and particularly at the low frequencies, what I find hard to get my head round is how 2x attenuators stacked, performs worse than only 1x at the low frequencies. Whats also slightly concerning is no 32Hz as part of their test. Would be frustrating to spend 300 odd quid and a few hours and not get a satisfactory result!

That Zehnder manifold looks like it costs over £500 with all the necessary parts!!!! Think I’ll look into a few more options first!

Thanks. I’ll look into it. I’m about to go away for a week so nothing much will be done until after that. This is the reading from 1m away from bed 1 terminal.

Are those results for both used in conjunction with eachother?

Not sure how I missed that. I just downloaded it, but not sure what I’m doing. The 1st picture is with phone microphone a few mm below the centre of the terminal in bed 1. The 2nd picture is the same test in bed 2. Obviously the results are jumping around a bit - possibly as I’m not that still! Only a snapshot in time, but it does appear that bed 1 is slightly more weighted to the lower frequencies than bed 2 for whatever reason. unit currently on 30% as someone in the bath!

If I had any idea how to get hold of or use an audio spectrum analyser…!! Are there any iPhone apps any good?

I’m 99% sure it’s noise from the unit though. If foam lining the manifold did absolutely nothing, then I doubt lining the plenum will?

An update to this. I tried lining the manifold with acoustic eggbox foam, on all sides. It made absolutely zero difference. I’ve noticed that running the unit at different speeds makes no difference. It just changes the pitch of the droning noise slightly. The unit is only set at 20% anyway as that’s all that’s needed to meet the airflow in the various guidelines. Turning it down to the minimum 15% the unit can operate out doesn’t improve matters. I’ve also noticed that the noise is significantly worse in bed 1 and the dining room/kitchen supply terminals. The only 2 rooms where there is currently a double run of 75mm ducting from the manifold (and roughly double the airflow). These are also the 2 longest runs! The other 3 bedrooms are just about acceptable, whereas bed 1 in particular definitely isn’t. I noticed that in certain areas of bed 1 and with your head turned a certain way, you can’t hear the noise. Unfortunately my pillow does not fall into that category! The terminal is located past the foot of the bed and to the side, so it seems to be a normal position for it. If I close the terminal completely in bed 1, it stops the noise, so it can’t be noise transmission through anything other than the ductwork from the unit itself imo. It’s not the terminal making the noise either because it still makes it even when it’s removed and the ceiling plenum visible. I’m going to have to look at fitting a proper silencer (not the useless semi flexible one I currently have). It’s doing to be pretty awkward, but I think doable if it’s 5-600mm in length. Diameter is not really restricted. Any suggestion on all the above? Which specific silencers at that length are best? I’ve looked at Lindab, but they only seem to do 160mm - slightly annoying as my ductwork is 150mm! Thanks.

Which flexible attenuator did you use on the ductwork to bedroom? How did you adapt it onto the semi rigid ducting? I have a double run to the bedroom

Thanks guys, I think that explains it. It was mainly through interest. Nothing is really wrong. I'm not planning to change the boiler as it's not very old. System is sealed with expansion vessel and pump in airing cupboard - so it effectively works as a system boiler, just the EV and pump are outside the boiler, which is actually preferable imo. I will be swapping out the existing controls for Vaillant and running PDHW when I get a spare minute

Leaving aside any comments re why I want to know/is this a good boiler at least initially... Can anyone explain why the figures for nominal heat output and modulation don't seem to tally up with eachother. Interested as much as anything and can't find any info.

Most people CGAF about CO2 in my opinion. Certainly not enough to commit to spending vast or even modest amounts of their money on. Far more important things to worry about than reducing a gas that is important to us, has no effect on human health and may or may not be causing some small amount of global warming.

Or use gapotape. Expensive though

I’ve actually got a Sunsynk. 5.5 I think it is. No complaints after a year. &nbsp I’ve wired it to run some circuits in island mode when power goes out too

Why not just get an inverter that will allow you to generate and use the full extent of your solar array, but only export the small amount that is allowed. Make sure you have enough battery storage to keep you going for at least 24 hours with no generation and don’t wildly oversize the array if you can’t export much as it’ll only be of any (limited) use in the winter/low sun days.

Tried that and it made no difference. I think vibration would be dealt with by the flexi silencer anyway. I’m pretty sure the noise is from the unit and the silencer isn’t dealing with it effectively. The fact I have spiral ducting and a metal box as a manifold aren’t helping either, when some others have silencing material in their manifolds/foam ducting. I just need to find time to take it apart now

Thanks all. It seems I’m not the first to come to the conclusion the BPC flexi silencers are not good, so it’s either replace that - probably with something homemade due to the awkward position of it. Or, line the manifold with acoustic foam to see if that can work as a second silencer. Which is probably the easier option, so the one I’ll try first.

Do that with that Type AC RCD and he won’t be fitting an EV charger to it though. You need Type A or ‘better’ RCD protection to fit an EV charger. It also needs to be double pole/switched neutral, which rules out the kind offer of the C40 RCBO above, which is only single pole, albeit Type A. Nothing necessarily wrong with that board. Swap out the RCD for a Type A and fit some Type A RCBO’s in place of the unprotected MCB’s and it’ll be fine. If you go to that extent though, you’re most of the way to a new board. If I was asked to fit an EV charger there on a budget I’d be fitting a 100A Type A RCD in place of the existing and an MCB for the charger. I can’t recall off the top of my head if the Wylex switched neutral RCBO’s fit that particular board - they keep changing them and they’re not always backwards compatible, it’s a bloody pain.

What silencer do you have @JohnMo?

Thanks, I’ll definitely give that a go. My gut feeling is that it’s fan noise/noise from the unit being transmitted through the ducting though. I don’t think the ducting even touches the plasterboard as it passes through. It’s then just foamed in.