Re: Re: Underfloor heating and HA control?

[Lehane Kellett <lehane@xxxxxxxxxxxxxxxxxxx>]

Just to add to Ziggy's comments.

The overshoot on the UFH is about 1 degree on our the slab, it would be
less for a wooden floor I'd guess. So currently boiler demand cuts off
at 24C slab temperature (house occupied, 'day')  but runs the UFH
circulation pump for another 10 minutes and reaches about 25.25C. It
calls for demand again at 22.5C
It is (right now about 13C outside/21C room) cooling at 0.6C per hour.

We have electric UFH upstairs which uses the mfr stat but with HA (xAP)
control of the timing/occupancy. We also have 'wet' towel rails and a
sensor (later a humidistat too) in the bathrooms and radiators
elsewhere. All the rads go back to Danfoss manifolds(like UFH) in Node 3
in 10mm Speedfit with 24V thermal actuators on each of 12 circuits.
There are two manifolds and each has a circulation pump. There are also
two proportional mixing valves which can mix flow/return (not running at
the moment as I need to add the pipe sensors). All are under HA control.

As to DHW loop, we have a circulation loop from the thermal store/boiler
room in the shed, underground in insulated pipework, to a heat exchanger
in Node 0. The DHW is fed from this. The loop is pumped for a minute
every 15 when the house is occupied or continuously when there is DHW
demand, from a flow switch. Other than the occupied signal this is
outside the HA system and controlled by the industrial PLC. There are
two more heat exchangers (spa, changing room).

Probably way too much detail!

Lehane



Nigel Giddings wrote:
>
> Hi Ziggy,
>
> Good to get a real world experience !
>
> >From what I have heard it takes everyone about 2 weeks to sort out
the
> thermostats. ..
>
> I wanted to pick up on your temperature overshoot during the evening
and
> how you cope with it now, five years later. Do you have programmable
> thermostats or do you manually turn them down?
>
> Does this overshoot vary day to day due to shifting of the time of
dusk?
>
> Do you have adolescents in the house?
>
> How do you find the heating in the Bathroom, is it supplemented with
> Towel rails?
>
> Do you have a DHW Loop?
>
> Thanks in advance
>
> Nigel
>
> -----Original Message-----
> From: rb_ziggy [mailto:rb.lists@ntlworld. com
> <mailto:rb.lists%40ntlworld.com>]
> Sent: 19 October 2006 23:40
> To: ukha_d@yahoogroups. com <mailto:ukha_d%40yahoogroups.com>
> Subject: [ukha_d] Re: Underfloor heating and HA control?
>
> Just to add, i'd agree with the thermal store tank coupled with a
> condensing boiler for efficiency.
>
> We used Nu-Heat. They have systems for installing under timber decks.
> We have in screed on the ground floor and under a timber floor on the
> first.
>
> I have to say, I'm really not convinced about HAing UF heating. In my
> experience, it's not necessary. We worked out a comfortable setting
> on a normal 8 zone system nearly five years ago and have never touched
> it since. It just works away in the background and the house stays at
> a comfortable temp all year - we never notice the heating come on in
> the autumn or off in the spring! I'm sure it would work equally well
> with full HAing but I'm not sure about better.
>
> However... in our case we do have a rather heavily insulated house and
> I think that helps because it cools slowly and any external changes
> seem to take quite a while to become apparent and that allows the any
> lag in heating kick-in to go unnoticed. On the other-side, we found
> that we needed to turn down the heating earlier in the evening
> otherwise the cooling lag could result in a rather overheated house
> but that was sorted within 2 weeks 5 years ago.
>
> Just to prove I'm not iredemably luddite on this, I would (did) put
> (dallas) temp monitoring in in several places though. These display
> on the touch screens around the house updated everyminute to 2 decimal
> places!
>
>
> [Non-text portions of this message have been removed]
>
>
>
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