dpmiller

^ don't discount how strong and turbulent the convection currents will be inside the tank with the heat rising off the coils...

what *is* the comparative cost then?

Is there a pole transformer or a "substation" in the vicinity?

the base of the tank sits around or just below flow temperature.

TS has a 3m2 ASHP coil in the bottom third and a DHW coil in the upper third, roughly. Flow from the ASHP passes through the bottom coil at all times except if cooling is required, when it's bypassed using a 3-port valve. I'd originally done this to enable blending of HP and buffer volume in parallel but that's never actually needed. 2-port zone valves divert the flow out of the coil to the manifolds and if neither manifold is calling, an auto bypass valve sends all flow to return The boiler stove is plumbed direct to the TS (through a laddomat-style anticondensation valve.

Yes, DHW priority like any other ASHP flow temp during DHW is controlled by the ASHP using it's own deltaT curve It's a World Heat TS with a standard 3m2 coil and two immersions both on PV via an iBoost but... All heating flow also passes through the TS so the TS acts as a buffer volume. Heating flow (UFH *and* rads) is about 42c, the tank is never cold... And this means I can heat the whole house off the immersion heater *or* the boiler stove, as a failsafe

I've two pockets but they aren't really far enough apart. One just above the coil, about 2/5 up, the other halfway. I'm using the upper one. Hysteresis is 1.5c plus an overshoot of 0.5 (overshoot give the inverter a chance to ramp down rather than turning off) Tank setpoint varies by time but is between 50 and 54, but the top of the tank tends to end up 3c or so above setpoint

TS works fine for us with the ASHP but sensor pocket position and hysteresis setting is critical, as well as minimising the time it takes for the HP to ramp up towards full power. Which means plenty of flow and the flow modulated by the HP...

Ummm, all fibre round here is overhead.

source for that info?

request a survey through their developer portal. In my experience it'll probably cost you a couple of hundred quid but it'll get roadblocks shifted.

how long does it take the protective chlorine in mains water to dissipate?

Is the earthing then for galvanic or lightning protection?

Same here, yesterday. Whole tank above 90c...

I wouldn't overthink it tbh, they just... work.

yes, they cycle on and off, kettling away happily. And have done for decades. Elements last a very long time as the base-down orientation keeps the electrics cool...

standard 3kW element @SteamyTea

no it can't get plugged. the tank would need to be hotter than the output of the willis for that to happen aside/ you can however if you're careful use the willis as an instantaneous- once it's on for a minute or two, opening a hot tap gently will take the flow *through* the heater...

^ yes. whenever the water entering the willis from the bottom of the tank is hot enough to trip the stat, the whole tank is hot and no more energy will be requested.

thermosyphoning is exactly how a Willis works. It's why we love'em here in NI- piping-hot water to the top of the tank in minutes for a quick basin of dishes, or a whole tankful for a bath in an hour. You don't need the stat set too high to get the flow going either, so I'd opine it would match a diverter well.

Absolutely. But it would be *incredibly* bad luck for both the 'stat's redundant overtemp AND the T&P valve to both fail.

I can't say I've ever thought of accurate calibration as a risk of any kind, moreso when there's a failsafe anyway...

does the temperature drop overnight?

my VOIP provider ported the number from BT for a small fee, and I'm using a Cisco SPA232D ATA and our previous analogue phones.

work out how many kWh you're putting in during your heating period vs how much it would take to heat the whole tank