ASHP & triple glazing

[Joeboy]

What are the nylon screws you all mention? I can't seem to find anything that isn't for attaching stuff to the wall.

Sorry Andy, thats what i meant, screw the lot to the wall using a nylon screw or at least a screw sheathed in nylon to reduce bridging. Hence the links i added
The plaster has popped off of most of our screws now on the gable wall and held elsewhere, but there is a bit of play in the wall when you push, so these just need retightened then covered again if we were to leave them ans not add more insulation.
I would prefer larger washers holding it all together though as you can see there is nothing but a wall plug and the screw currently.
But you do get a colder spot visible on thermal that way.
No condensation etc visible with naked eye, so no actual cold bridges, but it is visible with a thermal camera so will be having an effect.

Joe wants to foam it to the wall, so i suggest he screws the pir to the wall with nylon, then foam the pb onto the pir which should reduce the cold spots.

I'm not looking to foam anything. I'm looking to bond the pb to the pir via contact adhesive and if that works, bond the pb/pir sandwich to the vertical wall with screws as back up straight through the lot and into the existing timber frame. This may not come to pass due to contact adhesive performance but I'm ever hopeful. who knows where this will lead! We may foam yet.

Although I am surprised at the nuance and varied paths possible in a job that seems simple at first pass. More going on here than.i thought.

[Joeboy]

If you go metal screws, this is the type of fine thread to avoid https://www.screwfix.com/p/easydrive-ph ... pack/16374
This is the one that worked. https://www.screwfix.com/p/easydrive-ph ... pack/54411

I used the original timber and it was just too tough for the fine thread to go in.

Cheers.

[NoraBatty]

I'm not looking to foam anything. I'm looking to bond the pb to the pir via contact adhesive and if that works, bond the pb/pir sandwich to the vertical wall with screws as back up straight through the lot and into the existing timber frame. This may not come to pass due to contact adhesive performance but I'm ever hopeful. who knows where this will lead! We may foam yet.

Although I am surprised at the nuance and varied paths possible in a job that seems simple at first pass. More going on here than.i thought.

Sorrt Joe, grabbed the wrong end of the stick. Too much sherry

You want the fit of the insulation to be as tight as possible. The pb can be thrown on and not make much difference, but trying to wrangle and modify a lighter pir board to a tight fit is easier than a heavier ipb one.
Think about gluing the pir to the wall first ensuring a super tight fit. You can then alu foil tape the joints, then glue the pb to it, even adding an offset seam if you like, and then mechanically fix.

[AGT]

Would it not be easier just to stick prefinished plasterboard already stuck to foil insulation direct to the wall?

No timber required, quicker easier install,

That's clever, make up my own Sandwich boards on the horizontal. Could weigh them down with plate weights then fire them on as one pre prepped package once dry. That really is clever.

The temp difference within the room. 17.1 to 17.3 on the bad wall and 18.9 on good internal walls. I'll.keep looking for prebuilt all in ones. The £8 per can for adhesive kills the price run though. I'd rather pva the plasterboard to the pir foil backed board then screw through both to known fix points with same glue on back of pir foilboard as back up. This is just me playing in my mind. I'll happily pay full whack but the fun isn't in just doing that.







Me n swmbo use this spray contact adhesive in our furniture side of things. It really is excellent. I wonder?

https://www.poundwholesale.co.uk/151-he ... 00ml?gQT=1

I'm pretty sure we could make up a 1 ft sqr test piece and see how it goes?

Sorry Joe, I meant just buy them already stuck together to save any messing about, then stick them to the existing wall, a few mechanical fixings for fire protection and that’s it

[Joeboy]

Would it not be easier just to stick prefinished plasterboard already stuck to foil insulation direct to the wall?

No timber required, quicker easier install,

That's clever, make up my own Sandwich boards on the horizontal. Could weigh them down with plate weights then fire them on as one pre prepped package once dry. That really is clever.

The temp difference within the room. 17.1 to 17.3 on the bad wall and 18.9 on good internal walls. I'll.keep looking for prebuilt all in ones. The £8 per can for adhesive kills the price run though. I'd rather pva the plasterboard to the pir foil backed board then screw through both to known fix points with same glue on back of pir foilboard as back up. This is just me playing in my mind. I'll happily pay full whack but the fun isn't in just doing that.







Me n swmbo use this spray contact adhesive in our furniture side of things. It really is excellent. I wonder?

https://www.poundwholesale.co.uk/151-he ... 00ml?gQT=1

I'm pretty sure we could make up a 1 ft sqr test piece and see how it goes?

Sorry Joe, I meant just buy them already stuck together to save any messing about, then stick them to the existing wall, a few mechanical fixings for fire protection and that’s it

No worries, the game has moved on. Looking to preserve the coving and reskimmed ceiling. Plan now is to cut out that wall up.to the coving edge remove all pb, frame as needed, insulate and resheet. I am now in the realms of "is earthwool roll enough"? As the rest of the original house is fitted with rock wool I guess the answer is yes?

I had a wander about the groundfloor this morning and sure enough, even on a mild day the rest of the walls are up about 18.8 degs with ashp set to 19degs. The wall to be worked on remains at 2 degs below this.

Fintray, do you run your dhw at a set rate or on auto? I had alarms come back on the oem so have set pump to 50% speed and no alarms. Remains to see if that speed is enough for full heat potential transfer to cylinder.

[Fintray]

Fintray, do you run your dhw at a set rate or on auto? I had alarms come back on the oem so have set pump to 50% speed and no alarms. Remains to see if that speed is enough for full heat potential transfer to cylinder.

I've never had a problem with air showing in the system but your last screenshot shows your flow during DHW is doing the same as mine.
When mine does DHW the flow drops to 77.5% of the flow seen during heating and yours now shows a reduction to 75.3% so I'm assuming they are now configured the same.

[Joeboy]

Fintray, do you run your dhw at a set rate or on auto? I had alarms come back on the oem so have set pump to 50% speed and no alarms. Remains to see if that speed is enough for full heat potential transfer to cylinder.

I've never had a problem with air showing in the system but your last screenshot shows your flow during DHW is doing the same as mine.
When mine does DHW the flow drops to 77.5% of the flow seen during heating and yours now shows a reduction to 75.3% so I'm assuming they are now configured the same.

Great to know, I've upped it to 60% and I'll leave it for a 25hr cycle.

[Joeboy]

Just dropped the rubbish off and there is the gentlest of whispers from the HP. Getting used to it doing its thing now.




Here's what it's doing when that photo was taken.



Looks like we might get a few kWhs from PV today? Let's hope it hits a 6X to the home thru the HP.



Dec 23


Dec 24 HP went live 11th Dec.

[Adokforme]

Thanks for posting Joeboy that's a really inpressive performance especially when compared to last years figures and so useful to know for future reference. Good to see Fintray's figures and other suggestions accompanying as well.
Having gone down the path of A2A and been very happy with it I had wondered if A2W systems were worth all the additional expense and upgrades to rads etc so it's great to learn of use cases where results are so positive.

[Moxi]

Thanks for posting Joeboy that's a really inpressive performance especially when compared to last years figures and so useful to know for future reference. Good to see Fintray's figures and other suggestions accompanying as well.
Having gone down the path of A2A and been very happy with it I had wondered if A2W systems were worth all the additional expense and upgrades to rads etc so it's great to learn of use cases where results are so positive.

I would think folk who have the heating covered by A2A would be able to use a ASHP hot water cylinder to provide the DHW at a fraction of the cost of a full system? You could duct it to use house air in winter and external air in summer to make it as efficient as practicable?

I’m still wondering about something similar myself as we appear to need very minimal heat but with a family of small boys and large dogs the DHW demand seems to be fairly high. High enough for me to be attempting to model our DHW consumption over winter to add to the house data for overall energy use.

Moxi