Best wireless programmable thermostat?

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Right, I'm fed up with my incomprehensible Vaillant VRT 360F. I had to look up the instructions just to turn the heating off for the summer!

It's difficult to programme, has useless indications and sends luke warm water round the system and takes for ever to warm the house on a winter's morning.

What I want has to be simple, logical and efficient, ie warms the house fast. I've got 37kW available from my 937 but most winter mornings it feels like 3.7kW!

I have recent experience of 2 x 24kW and 1 x 31kW Vaillants in my 3 holiday lets and they warm the flats really fast so I want that kind of fast warm-up from the 937 in my 3-storey 3 bed town house.

Can anyone really recommend a suitable wireless stat for me? I'm not bothered about using the eBus controls on the vaillant and expect to revert to basic on/off thermostatic control with a programmer, I, and the missus (you know what I mean), can understand.
 
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Yuor existing control is probably "open Therm" protocol, which as the room temperature rises gradually reduces the boiler flow temerature to the radiators, this is good because it keepsa the boiler in condensing mode for much longer, however it can give the illusion of lack of heat as you describe, you will find that the boiler runs for longer periods of time at a very low firing rate. However if you dont want this IMHO the Honeywell RF is one of the best, however i do think your existing control will save you money in the long run! ;)
 
Have you checked to see what D.O is set to?

Probably the same as it came out the factory 28kW or so.

Try setting it at 15 and you might get hot water flowing round your radiators ;)
 
Honeywell 921/927 depending whether you want separate daily temps or set the same for everyday cost around 100 quid
 
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Same recommendation as Namsag, however you'll probably find that if your Vaillant one is set correctly it will do what you want (I agree they are bloody confusing at 1st though)
 
Vaillant do not use Opentherm, they have their own system.

The 937, out of the box, provides 28kW for heating (and 37kW for hot water). That's OK, provided you have 28kW of radiators. But if you only have 10kW of rads, they will be unable to dissipate the heat produced by the boiler, which will cycle on and off and the water will never reach working temperature. You can reduce the max output of the boiler by setting d.0. Set it to slightly higher than the total output of your rads.

To find the total output of your rads, use the Stelrad Elite Catalogue. This will be adequate for flat panel rads, but not for designer or cast iron types.
 
Yes you're right it does only produce 28kW on CH. I stand corrected.

However setting D0 to anything other than full output is pointless for this Vaillant. It modulates the burner output to match the flow temperatures down to a minimum of 12kW iirc. So why range rate the output at all? It does it by itself and Vaillant says not to bother in the instructions.

The dwell time between firings if cycling is likely to have a far greater effect as this allows the water to drop far lower than you would wish before re-firing.

Thanks for the thoughts guys but I'll go for a new programable thermostat and see how it fairs this next heating season.
 
If you want something really simple I fit the Seimens RDJ10 Rf stat for old and young, simples.
 
Tipper - By setting "d0" to a lower setting, the boiler won't reach it's upper limit temperature anywhere as quickly, so no delay before refiring as has been said this is exactly why you should set the Heating output to match your heating load! ;)
 
Yes you're right it does only produce 28kW on CH. I stand corrected.

However setting D0 to anything other than full output is pointless for this Vaillant. It modulates the burner output to match the flow temperatures down to a minimum of 12kW iirc. So why range rate the output at all? It does it by itself and Vaillant says not to bother in the instructions.
Yes, but have you worked out the total output of your rads? If that is less than 12kW, your boiler will continually cycle, irrespective of the d.0 setting. Every time the boiler starts up it ramps up to max output and then reduces the output to maintain the correct temperature. Obviously if the rads are only 10kW and the boiler can only modulate down to 12kW the boiler will cut out, cool down and restart.

The dwell time between firings if cycling is likely to have a far greater effect as this allows the water to drop far lower than you would wish before re-firing.
Exactly. That is what is happening. It has nothing to do with the thermostat.

PS
You are not the first person on this forum with this problem. The solution has usually been to set the boiler's max output to match the output of the radiators.
 

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