Quick follow-up on my Megaflow/water-hammer issues (thanks to all who replied!) - I caught it yesterday morning at the critical moment, and heard it just start to hammer - followed by a small thunk apparently from the bypass valve, and the hammer clearing. So sticky bypass valve is now prime culprit (but will have to wait until warmer weather for me to replace it).

New question - I have just replaced my old-world Danfoss electro-mechanical thermostat with a modern Danfoss unit (RET2000B).

This in its factory settings does simple on/off control - but also (via DIL switches) has what they call "chrono" settings that appears to be designed to reduce short-cycling by the boiler.

The explanation in the manual (and Danfoss website) is sparse to say the least.
It merely says it can do 3, 6 or 12 cycles, and 6/12 is for radiator systems and 3 cycles for underfloor heating. I'm guessing this is boiler-cycles per-hour?

Can anyone enlighten me about exactly what it does, whether it is compatible with any gas boiler, and if it's likely to have a positive impact on economy?

On Mon, 30 Jan 2017 00:56:48 -0800 (PST), "
wrote:

Quick follow-up on my Megaflow/water-hammer issues (thanks to all who replied!) - I caught it yesterday morning at the critical moment, and heard it just start to hammer - followed by a small thunk apparently from the bypass valve, and the hammer clearing. So sticky bypass valve is now prime culprit (but will have to wait until warmer weather for me to replace it).

New question - I have just replaced my old-world Danfoss electro-mechanical thermostat with a modern Danfoss unit (RET2000B).

This in its factory settings does simple on/off control - but also (via DIL switches) has what they call "chrono" settings that appears to be designed to reduce short-cycling by the boiler.

The explanation in the manual (and Danfoss website) is sparse to say the least.
It merely says it can do 3, 6 or 12 cycles, and 6/12 is for radiator systems and 3 cycles for underfloor heating. I'm guessing this is boiler-cycles per-hour?

Can anyone enlighten me about exactly what it does, whether it is compatible with any gas boiler, and if it's likely to have a positive impact on economy?

The usual way an electronic thermostat reduces short-term cycling is
to artificially introduce a few degrees of hysteresis.

This one however appears to be a bit smarter, and is able to ignore
temparature changes crossing the setpoint for x times in y period.

Something like that.



--

Graham.

%Profound_observation%