phatboy

You likely have less extract vents than supply, so open them up a bit more! You also need to set the "Ckr Hood Supply" and 'Ckr Hood Extract" to 100%, even though you don't have that installed. (BPC advised me of this)

I'd like to hear the outcome too.... our project is currently with the engineer, but hoping to use either Celcon Plus / Jumbo, or Durox Supablocks with thin joint, so will need to do the same thing. Our block layer is a trusted eastern European guy, who laid it there for years before coming to the UK... he thinks we are backward for using concrete blocks and 10mm mortar beds.....

Just been on the phone to Forterra to enquire about thin joint, and apparently they no longer offer it for Thermalite, due to some kind of split of the company. Nor are they aware of anyone manufacturing suitable adhesive, that would sell it. So that's Plan A in tatters! Can anyone recommend other aerated block manufacturers who offer the full solution? I am aware of Celcon, however being in Jersey, they won't send less than a truck full, and most people here are still building in standard block, or aerated with standard mortar joints. Thanks Tim

Also I'd recommend getting a silencer for the extract side of the system, before the MHRV unit. I found it quietened down the vents to near silence.... it also provided another convenient flexible joint!

Assuming it's a Vent Axia unit.... - I got the wired controller with cable new on eBay for £20 - No wired boost switches.... the shower relies on the in-built humidistat, and I hooked up a variable input voltage relay to the cooker extractor motor side, and used one of the volt-free connections on the main unit When I did mine 2 years ago they only did 1 type of pipe (red), which seems to be the premium one now!

Sort of, but quickly decided a flexible one would probably help me with funny angles a bit better... and it did. Since then, I added a silencer to the domestic side extract too, and it was worthwhile. Also, the way I fixed the unit to the roof wasn't good.... I used screws, and over time them moved and the unit tipped a little. I had to re-do it with some M8 bolts. Can't believe I did this 2 years ago!

Thanks everyone! @scottishjohn makes a good point about time spent, and i don't think I could handle 3 solid days of cutting the holes! When we get to trial holes we will find out if there is enough space for an extra wall. If not, then will need to re-assess! Will see if the cutter @nod mentions is available locally, although I cannot find it on Smiths Hire site, as an option.....

Hi, I am a long way from beginning any build work on our extension (1 year), but trying to gradually get everything worked out in my head I will need to install about 45 beams for the block and beam floor, with 1 end into the existing solid 9" blockwork (block on flat). What's the best way to do this? A 4" grinder won't get me anywhere deep enough, and a 9" grinder risks nearly creating a pair of cuts the full length of the building which cannot be satisfactory. Do I just need to use a small grinder, and spend a lot of time with a big SDS drill getting the pockets cut in properly? Unless the engineer specifies a sleeper wall, but that would come with its own issues! Thanks!

I used Soudalduct, and found it was thicker and a lot more 'sticky' than caulk. It seemed to grip as soon as the 2 parts joined. It's hardly expensive, and I used about 3/4 of a tube for the whole install.

I had this issue a couple of months back... not especially cold but very wet weather so high RH. Sentinel Kinetic BH. My issue was the unit was not mounted quite level (Had rotated a bit of it's screws into the roof beams), and so some of the collected water was passing the drain hole behind the Summer Bypass, and running to the front of the unit. The front PCB got wet, and the unit went haywire, reporting weird errors and fans spinning up and down. I levelled up the unit this time bolting it to the roof timbers, and a helpful friend cleaned up the circuit board for me, and everything is now fine. I keep checking the unit in the loft, and 2 months on no liquid has been seen. At the time I also cleaned the drain hole behind the Summer Bypass, and removed the bung to the front of the drain (I use the rear one), and checked it was all clear, and poured a little water in to be sure.

Pretty much this, got me a tolerable coil. Assistant downstairs feeding and untangling, me in the loft having cable tied an initial loop, then try and hold the rest together, and then lash it in electrical tape, job done!

I can see no reason not to, and some people do have genuine concerns about the noise for neighbours. It will mean a slightly higher fan speed, so as long as your chosen MHRV unit has sufficient headroom, it would be fine I reckon.

I am in a high humidity area too (1km to the sea), and I had to set the humidity sensor way up to 84%... it still always kicks in for showers, but less so for kettle boiling and general 'moist' air. Fairly sure the installation manual says set the internal temp to about 4 degrees C higher than you would actually want it to be, to make the summer bypass behave.

Ours runs 24/7. It runs at normal rate all day, and low rate at night. It also boosts foe 2x half hours each day to help keep the air very clear, and also boosts when excess oisture is detected (Kettle, shower), and boosts via a relay when the cooker hood is turned on. I started using low rate at night, as it was just about audible when in bed, as the bedroom terminal is close to the bed.

Hi all, I can't be the first person to have a fight with leftover 75mm flexible pipe (32m), and trying to re-roll it fairly tight. Any pro tips? I don't have access to a large cable drum, but thought about using an offcut of 8x2, and attaching a couple of 2x1s to the ends to form a sort of cable drum. Would welcome any easier solutions though! Cheers Tim

The blue Domus seems to be the same spec as the red Airflex, and £30 cheaper. The other ones nothing much is mentioned.

I have the same unit, and did find it to be a little noisy! I installed the same ducting kit from BPC and no complaints. I added a silencer on the extract side too, and since then it's very quiet in the house. Since I did mine, they seem to have cheaper 75mm pipes - mine are all red, but green and blue are cheaper, and I cannot really see why!

For my bathroom i just rely on the MHRV units built in humidistat. For the kitchen, I got a clever relay with a wide input voltage and a timer, and connected it into the wiring for the extractor fan motor. So the system boosts when the extractor comes on, and remains boosting for 30 minutes after.

I would ask what professional qualifications he is looking for. The answer will probably be 'there aren't any', in which case re-submit your results!

Stranded?! You're not using jacks and panels then!?

Hope you chose a nice colour! Just the 1 roll?!

My BPC manifolds were totally un-insulated. I fitted them to a board on the ceiling beams, and then rolled the additional 200mm loft insulation over them. Pipes from them to the main unit are in the process of being insulated with 50mm rockwool

I used Excel cat6 cable, was about £90 a box I think. No issues at all. If you then have someone 'qualified' punch it down to an Excel panel and mods, they warrant it for 25 years.

I found cable basket was way way cheaper than tray, despite being just as good. £5 for 3m I recall, for a 50x55mm one

I don't know really, there is the required 10mm under the doors. The room has a supply valve, so heat isn't likely to be sent into the room from the rest f the house when the door is closed?