HughF

There isn’t a ‘wrong way round’ for lockshields and TRVs (although logically, my head still tells me the trv should be on the flow), but if your rads are plumbed TBOE then it’s important than the flow is to the top, otherwise the rads will be short circuited.

I must say, I've been quite pleased with the fan coil option for heating the kitchen and hallway - they definitely seem to work well.

We leave all the doors wide open…. Trvs in the bedrooms stop them getting too hot. Although in the downstairs, there’s no such thing as too hot for my wife. She’s quite happy if it’s anywhere between 22-25. It seems to work out quite ok for us. The troublesome northern room sits at 21.5 ish in these climatic conditions, and the rear of the house (with a new build extension to regs+) sits at 22 ish. I think it helped that I got the rad sizing pretty much bang on and I’ve only for one rad per drop off a 22mm ring. We actually only have two rads downstairs. The hall and kitchen are served by fan coils and the extension is ufh.

Modern lockshield valves are mostly junk, with a lot of the action happening in the last 1/2 turn. i tried and failed to get my system balanced too, and my k3 is always a bit cooler on the outside panel than on the inside. in the end i just wound them all wide open and jumpered the call for heat line with a wago connector. It runs 24/7 on weather compensation.

I run mine wide open on the isolators now that we’re up at the top end of the WC curve at 47.5 flow. Mine are just the smiths ecovectors with a simple thermal switch and two speeds. The bathroom one stays on 24/7 and the downstairs ones go on/off as required by hand. My wife is of a certain age so she often turns them off in a moment of meltdown.

How are you finding the self balancing actuator working for you? I've got £2.99 isolation valves on my fan coils and I struggle to throttle them down to get any meaningful deltaT across them without them being noisy...

Except, they probably wont... It'll end up as a system with a buffer/header, with another pump on the manifold, mixing down from 50 degrees...

Went with a pair of rotary isolators, one for AC in and one for AC out. Also went for a 2 module enclosure that can house a pair of MCBs to provide inverter input and output overcurrent protection. Decided to put the consumer unit <3m away from the inverter so no need for a switchfuse on the supply cable.

Mine are silent….. the incoming cold though, wow…. Must do something about that.

Temp was 37.5 (reheat threshold is 12.5 below target) and setpoint was 50. Everything behaving as expected, except it just sat there and didn’t fire up to complete the dhw cycle.

Honeywell…. Came on my Vaillant pre-plumbed cylinder. Hasn’t given any issue till now and it doesn’t have any aux contacts. I’ve got it wired up to the heating live, so it’s power-off for dhw .

Yep, certainly not the cheapest unit around…. Shame they don’t make a 5kW as well really…. It’s a little on the large side for most.

And modulate pump speed, if you’ve got a unit with a pwm pump.

Hiccup on mine today too. I get a phone call this evening saying ‘the heating went off this afternoon’…. Asked for a photo of the panel, it had started to do a dhw refill but never started up the pump/compressor/fan cycle. So it was just sat there waiting for Christmas to come round again. No errors, and a power cycle seems to have fixed it and it’s now doing a refill, having woken up in heating mode.

My neighbours boiler flue is considerably noisier than my heat pump….

My current inverter has single pole switching on the AC in and AC out (manufacturers instructions), and the DC side is completely separate. Separate enclosure, separate breakers for the inverter and MPPT in/out. The new inverter (I'm installing a SunSynk 3.6kW into the house, and moving the AC supply over to that from the existing inverter that is currently in an outbuilding), has a built in MPPT with double pole isolation, but the MIs simply state 'provide a breaker if x amps on the AC input and AC output. I'll get what you mean about treating the supply to the CU as a standard install, and hence the >3m rule applies. One of these: https://www.tlc-direct.co.uk/Main_Index/Distribution_and_Switchgear_Index/Hager_SP_1/index.html Would do the job of the AC output protection, overcurrent protection for the meter tails to the CU, and a double pole isolation - provided I replaced the fuse with a 32a, to suit the supply cable to the CU. Or one of these, which seems far too cheap: https://www.directtradesupplies.co.uk/product.php/202439/fusebox-100a-fused-switch--63-80-100a-fuses---white-?gad_source=1&gclid=Cj0KCQiAwP6sBhDAARIsAPfK_wYt1JfB81akm_12qjDSLn3fpF8pvs4PSzmRgggHVlRRcM04sWMQmlEaAp_sEALw_wcB

Thanks for the input... I'm going to be running some 100x100 trunking underneath the inverter to help with the layout, should be easy enough to add a DP switch there.

I did ours at the weekend, a few bits in there….. well worth taking the time to check/clean.

Daikin are usually running 410a in their older models of altherma, moving to 32 in the newer ones. I’m in the ‘disable legionnaires cycle’ camp… don’t think my heat pump even has a feature for that.

Background: Offgrid place in dorset, 3.6kW inverter providing all the power. Landlord wants me to partially rewire the supply and CU. I've agreed with his electrician that I'll do the work and he'll sign off.. I've got a copy of the latest site guide and I know I'm not brown/blue colourblind so we're good to go. Question: SP Inverter output breaker (MCB) as specified by the inverter manufacturer (25a) feeding ?mm2 3-core NYY-J, 10m or so to the new consumer unit. Does this length of NYY-J, which is basically acting as the meter tails, need double pole switch-fuse isolation, or can I rely on the SP breaker at the inverter output for this? No issue to fit a switch fuse, I just need to know...

R32, inverter driven…. Still not a bargain, but it’s a start.

Yep, it seemed an ideal solution. Buy the smallest one (3.5kW) and just pump it straight to the loops with a fixed flow temp.

I thought the OP was purely looking for a unit to power the ufh loops in his garage/workshop or something, somewhere away from the main house?

Not for ufh, just set a fixed temp and pump the water round the slab…. Let it defrost from the slab…

The myson looks like a nicer product than the smiths… something I’ll consider when we do the bathroom renovation this year. Got a smiths 12v one at the moment and it could do with being bigger.