HughF

If there's an indoor sensor, then that's load compensation... Weather comp is purely outdoor sensor based.

Well, it works... floor is staying warm, house isn't cold...

best thing I ever bought.... hope you got jaws with it. I ended up spending close to £1k on jaws for my £80 gun. AFP101, modified to run on Lidl 12v batteries, angled jaws and a full set of M and U jaws.

I’ll post up the user manual when I’m in front of my laptop… the ivar mixer does indeed have two internal bypass’ both of which are adjustable. If it turns out I can heat the extension with only 27 degree flow then that’s all good, less losses all round. It would just be nice to have another pair of eyes looking over the manual with me. Appreciate everyone’s input on this.

that’s what I was expecting, it to respond quickly to a demanded flow temp when being fed with a considerably higher flow temp than the mixer was calling for. It seems completely disconnected from the flow temperature I see through the loop, which again is sitting at 27. Getting dT 3 between flow and return, and the floor is doing a nice job of keeping the extension warm, so I guess it’s working… it seems that no matter what I set the mixing valve to, it sits at 27.

Varies between 38-50 depending on the weather comp.

I’ll have a look and see what I can download. Some energy appears to be going into the floor, but I can’t get the flow temp into the loops above 26 ish.

Yep, I figured as much…. I think I had an incorrect assumption about how it blended the water, assuming that it would in fact feed water at the requested flow temp (I’ve set the dial to 33) until the return from the loop was at that temp. Instead it seems to be flowing quite cool. The heat must be going somewhere, the flow line is hot and the return from the manifold is cold.

Well, it appears to be doing something…. Heat pump is happier now there is more of a sink for its energy to go.

Air to air is what you want…. Forget direct electric underfloor. It costs a fortune to run.

Just put a plug into this and got it flowing…. It’s taking heat from the flow. But the loop temps aren’t coming up, is that normal? I’d have expected it to take as much flow as it can in order to satisfy the flow temperature, is that an incorrect expectation? The pipes into/out of the manifold are hot/cold…. And there is some warmth to the flow, but it’s not rising above 22.

Air to air, either a ceiling cassette in the hallway, or heads in each bedroom. Finest way to heat a house in my experience. Cheap and easy to fit, individual room control without the issues of zoning down radiators, fast to respond, don’t take up wall space for cupboards or other such things that radiators do.

Yeah that’s a pretty lousy spec for a new build…. We did a simple rear extension this summer, ended up 150 full fill cavity and 0.98 triple glazed fenestration products. 200mm pir in the floor. Emptied a couple of rolls of air tightness tape round the windows and cavity closers, used Compriband and fm330 around the windows.

I do have a contact at Brookvent but they are so utterly useless at getting back to you, I asked the manufacturer in Poland if they would sell direct and they will. sklep@brevis.com.pl And ask for Oliwia.

I used the Higroster humidity activated vents, they’re very nice and so far no complaints from my wife about noise or drafts. They are much better than the glidevale ones from bpc ventilation. We are going to ditch the dMVHR plan for the extension and fit three of these to the doors instead, saving the fused spur position for a future air-air

A month in, and an update on the smiths ecovector fan coils. they’re not bad, pretty simple things with zero electronics inside. The metalwork isn’t bad quality and the screws go back in when you take the covers off. Having the thermal switch means I can leave them switched ‘on’ and they’ll fire up when the time clock raises the flow temperature to ‘day’ mode. The fan isn’t as quiet as a good quality air-air unit from daikin, but I haven’t had any complaints about the noise. The 12v one in the bathroom does a good job of keeping that space warm and dry. Were they cheap, no….. do they do the job, yes. Would I prefer the reverso units, yes…. Did the reverso units fit the wall space, no…. 🤣 I’ve got one in the hall/stairwell area, one in the kitchen/lounge and one in the bathroom.

I’d need to check my calcs from loopcad, don’t recall them off the top of my head. 2.5l/min at 33 flow rings a bell. 16mm @ 150 ish centres in 100mm concrete, on 200 pir. 2 loops, 50m each. 15m2 floor area in a new extension.

All pressed up…. Didn’t even need my angled jaws 🤣

@JohnMo better?

Consider it done…. Nothing pressed yet and I’ve got 28 Ts in the bucket.

Making some progress… hopefully this will work.

‘New build, so will be airtight’…. You sure about that?

With the pump minimum set to 30%, I arrived on-site tonight to find all the rads evenly warm. Heat pump had been ‘on’ since 0600, the room stat is disconnected at the moment. I had throttled the fan coils down to get me as close to dT5 as I could, and left the rads all open, when I last played around with this on Sunday evening.

Ceiling being boarded tomorrow by the builders, and I don’t have a chance to drain down, so it’s plan B…. Lockshield gate valve between flow and return, CCTs on the flow line to give a couple of 22mm runs to the manifold.

Pipe in the corner is the flow, one out from the corner is return. I’m thinking close coupled Ts on the flow, loop flow and return with a gate valve, adjust to get delta-t 5 at this point. No different to if there was a rad on the end.