Programmable Thermostat + HW + Frost ... can't find!

[gball]

Having already bought two controllers which don't really do the job, I thought I'd better ask around!

Our house which has a normal (not combi) boiler wired up as fully pumped S-plan (one heating zone, vented HW). The property is empty for periods of time, and also used by friends (who may not have training in heating systems) so needs to be simple to turn on & off.

I cannot seem to find a single controller which meets all of the following:
1. Is temperature programmable (i.e. not just on/off controller)
2. Has integrated timed hot water circuit
3. The CH ‘off’ mode puts the thermostat into frost mode (5 degree)
4. Has a single control that turns off both the hot water and heating – either front panel or via a ‘holiday’ jumper wired to external switch

The sticking point is the frost stat. If that was not a requirement, I’d just power the whole boiler off.

So far the closest I have is the Danfoss TP-9000. This has a really counterintuitive control – rather than two nice separate mode switches for HW and CH, you have to press a hidden button to flip the display (and mode button) between HW and CH setting. Even with instructions, I find guests power off the heating but leave the HW running. It does has a separate ‘holiday’ jumper to allow an external switch... but that only powers off the CH circuit, leaving HW running!

I also bought the Heatmiser PRT-HW. This has a nice clear display but the buttons are even more unintuitive – and again the frost mode does not disable the HW circuit, and the full power off disables the frost stat!

Does anyone know a model which meets all 4 – either simple enough to have an intuitive (preferably ‘mechanical switch’) control, or supports a proper remote ‘off’ jumper (which sets both frost mode and turns off the HW circuit)

I’ve looked across the main manufacturers (Honeywell, Sunvic, Danfoss etc) as well as some more unusual (Heatmiser, Grasslin) I’m about to install an ugly triple-pole switch to manually trigger holiday mode and disconnect the HW demand – but on the Danfoss the HW indicator light will still flash on and off – confusing again.

 

[matt1e]

First off, What is the make/model of boiler?

 

[gball]

It's a glow-worm, but that's not really part of the problem (unless there is something very clever I hadn't realised!)

Specifically: it has no built-in frost stat, but it isn't sited in the house so that wouldn't help (I have added a frost stat to the outhouse). In terms of wiring, it's a standard permanent mains / switched demand / pump overrun connection, which I have wired in per standard practice (i.e. HW and CH demand drives two port valves, NO contacts on valves wired in parallel to boiler demand IN; pump wired from boiler overrun OUT.)

So I can work around the issue by either mounting a frost-stat and cutting power to the programmer... or by this DPST or 3PST switch. But neither solution are particularly neat (either the programmer battery goes flat, or the controller display don't correspond to actual setup) There's plenty of models which meet various 3 out of 4 requirements - so I can't believe there isn't a single box solution.

 

[scoobydo123]

http://www.myson.co.uk/products/touch_screen_thermostats.asp

Deffo has the set back for frost guard


Anygood?

 

[matt1e]

http://www.myson.co.uk/products/touch_screen_thermostats.asp

Deffo has the set back for frost guard


Anygood?

and seems to tick all your other boxes too

btw How did you get on with your stat problem Scooby?

Matt

 

[scoobydo123]

Yes the myson does it all (hopefully still got the tpi/load compensation as well as smart start), they are even bringing out a Wifi one soon. Cannot fault the old MPRT it really seems to control the boiler well apart from my niggle. Have turned it to Oil from Gas which has the effect of changing the cycles but still not ideal. Still waiting for something reasonable from GW by way of an explanation of how the logic works. They have been good so far and admitted that they have reproduced it in the lab think at one stage they were going to offer to send someone round but dont see that getting anywhere unless I have missed something obvious.

 

[gball]

Hi,

I took a look - the Myson actually looks functionally identical to the Heatmiser PRT/HW (which I actually bought first!)

Unfortunately, switching the unit to frost mode does not disable the hot water. And turning the unit off does switch off the hot water, but also switches off the frost mode!

So back to drawing board.