In article , VAG_dude writes
Just checked and the one that lets you choose propo or normal on/off is the Danfoss TP7000 range, avail as wired or wireless. I don't think they're as featuresome, pretty or as easy to use as the Honeywell but if it's pissing you off that much then it might be worth the 100quid it'll cost you to switch (for the RF version).
These guys have them at a good price and it's where I got my Honeywell from, they seem good to deal with:
Valliant supply a weather compensator. Once demand is below 12kW it will cycle, as it can't go down low, but in a controlled manner, not hunting. Some boilers can modulate down to 3kW.
with:
Cheers, think I'll try limiting the Honeywell to 3 cycles per hour and see how I get on.
They are efficient but the efficiency may vary at differnt modulation rates - half true.
To do what? The boiler decide on what rate to modulate. Only if the boiler is range rated can it be set once finding the most efficient level.
None are designed to be cycled. They should be engineered into a system the eliminates or vastly reduces cycling. Using a thermal store/heat bank with correct blending controls on the boiler return with "eliminate" cycling.
I used a regular boiler with the return temp, using a blending valve, set to just above dew-point, so the boiler never condenses. The efficiency was better than a condensing boiler on the heat bank without a blending valve.
Only half was true. Modern condensing boilers with load sensing controls will reduce the return temperature to the building/room load. A properly designed "system" is on part load for 90% plus of running time as the rads are designed to run at -3C outside and most of the time it is above -3C. In short, most of the time the rads are oversized. Insulation and incidental heat gain in the house will impact again.
Correct, what you have just said is half true. In this context efficient tends to mean maximum efficiency and as you say they are not as efficient at different modulation points which is what I said.
To decide if it is more efficient to let the boiler modulate.
Untrue, many boilers don't lose heat to the outside when the gas valve is off (they don't all blow the hot air out of the flu you know) and if its lost to the water it ends up in the heating system where it can be used to heat. The only time it isn't true is when the system no longer calls for heat and that is the same for any system.
That depends on what temperature you are heating the store to. If its above ~70C the condensing boiler will stop condensing and then it may be less efficient than a normal boiler.
You wrote, "Not all boilers are efficient when modulating", which was not true.
That was inane babble.
Total bollocks. Even if a thermal store is set to 80C setpoint it condenses
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