how to control heated floors with high latency

[Uncle Michael]

Just for completeness, it should be noted that for maximum heat uniformity (comfort) and energy efficiency, keeping the water temperature as low as possible and running the circulator pump continuously is the ideal.

[tome10]

I was trying to wrap my head around all this water heating in the floors and boilers (I live in Arkansas no need for that lol). anyways, i came across this lengthy discussion about boilers and delta-t values. Basically the discussion quickly morphed into flow rates, and how boilers are typically not well index'd for heat loss and installers typically install really oversized units in well insulated modern homes, and there doesn't seem to be a really good way to put the brakes on such an oversized beast. It was an interesting read. But, these guys are in MA, not Norway.

https://forum.heatinghelp.com/discus...-temp-too-high

[gd1210]

[Uncle Michael]

This calculation should be done by the designer/installer of the heating system. It's usually called a heat loss calculation, and doing it well is essential for choosing a heating system of the correct size. Also, modern condensing boilers typically come with a controller that can modulate the temperature of the circulating water, which ought to be the primary means of adjusting the rate of heat delivery. Turning the pump off is a relatively blunt instrument and provides very crude control, sort of like adjusting the volume of your audio system by turning it off or on.

[HAorso33]

This calculation should be done by the designer/installer of the heating system. It's usually called a heat loss calculation, and doing it well is essential for choosing a heating system of the correct size. Also, modern condensing boilers typically come with a controller that can modulate the temperature of the circulating water, which ought to be the primary means of adjusting the rate of heat delivery. Turning the pump off is a relatively blunt instrument and provides very crude control, sort of like adjusting the volume of your audio system by turning it off or on.

yes, I think this has been done in the old 'dumb' system I am removing now. They have marked each zone with the pipe length, and programmed the controller. So I have to try and recreate this as best I can.

It's a well insulated house (30cm if I remember correctly) and the heated floors give a very nice warmth. It responds kind of slow to outside temp changes, but it works very well.
Thanks for good inputs! I'll collect some data on how slow the floors cool and go from there I think.

I found a picture of the system. You can see the pipes on top of the heat spreaders. Then the wooden floors come on top.

https://www.dropbox.com/s/f6lr1luf6c..._4106.JPG?dl=0

[HAorso33]

Yes, I think this is the way to do it

[Uncle Michael]

They have marked each zone with the pipe length, and programmed the controller. So I have to try and recreate this as best I can.

I found a picture of the system. You can see the pipes on top of the heat spreaders. Then the wooden floors come on top.

Looks like a very well designed system. Are there flow control valves for each zone? If there are, you might be able to reduce the flow rate on zones that are overshooting. If there are none, that would be a useful addition to your system.

Do you have someone locally you are consulting with? I would expect there is a great deal of excellent experience in hydronic heating available in Scandinavia - perhaps even with detailed knowledge of the type of system you have - that you could call on for advice.

[HAorso33]

Looks like a very well designed system. Are there flow control valves for each zone? If there are, you might be able to reduce the flow rate on zones that are overshooting. If there are none, that would be a useful addition to your system.

Do you have someone locally you are consulting with? I would expect there is a great deal of excellent experience in hydronic heating available in Scandinavia - perhaps even with detailed knowledge of the type of system you have - that you could call on for advice.

I've contacted the manufacturer now, it would be nice if I could reduce flow rate.
I don't really have anyone to consult with, as the installers are mostly 'old school' plumbers. They now how to install and start the systems, but they don't know the gritty details of Homeseer and Z-wave. I'll reach out to the reseller as well, the might have some insight to share.

[wkearney99]

Just for completeness, it should be noted that for maximum heat uniformity (comfort) and energy efficiency, keeping the water temperature as low as possible and running the circulator pump continuously is the ideal.

Right, you want to avoid short cycling the pump as that'll put more wear on it than necessary.

Don't know if it applies here, but our geothermal setup takes into account the recovery time necessary to bring the zone to a desired temp. It starts the conditioning process with that in mind, aiming to bring the zone TO the desired time AT the scheduled time. Not just start the process at that time. The recovery time varies based on outdoor temp and HVAC mode. Cold days in the Winter and it'll bring the pumps on a bit earlier than warmer days near Spring. Likewise Summer and cooling.

[HAorso33]

Right, you want to avoid short cycling the pump as that'll put more wear on it than necessary.

Don't know if it applies here, but our geothermal setup takes into account the recovery time necessary to bring the zone to a desired temp. It starts the conditioning process with that in mind, aiming to bring the zone TO the desired time AT the scheduled time. Not just start the process at that time. The recovery time varies based on outdoor temp and HVAC mode. Cold days in the Winter and it'll bring the pumps on a bit earlier than warmer days near Spring. Likewise Summer and cooling.

That is exactly how I want the system to work! I can use weather plug-ins to predict temperature in two hours and adjust the system accordingly.