outdoor temperature indoor thermostat

[YAPH]

I'm doing a job where the customer wants underfloor heating in the kitchen but the heatloss will require more than the UFH can provide, so I'm going to put in a plinth/kickspace heater as well. Since the latter will only be needed during the coldest times of the year it occurred to me to have it on a thermostat that senses the outside temperature. Ideally the thermostat itself should be indoors, so I want one with a weatherproof(able) remote sensor.

I don't recall seeing such a beast anywhere so before I start butchering electronic 'stats does anyone know of one off-the-shelf?

Or have a better idea for how to control this setup, that I haven't thought of? :-)

[Harry Bloomfield]

YAPH was thinking very hard :

Surely it is the indoor temperature which matters?

Just put the plinth heater on a stat set a little below what you would normally expect the UFH temperature to manage to maintain.

[BigWallop]

Can't you get more loops into the heating circuit? You could supplement the UFH with a pipe around under the units, against the wall. Like a simple heater pipe run from the same flow as the UFH but fixed against the walls of the room. It would keep the wall space warm to reduce the losses through them.

I don't think I've heard of a kitchen needing huge amounts of heating. Do they use the room as a living space?

[Tim S]

YAPH coughed up some electrons that declared:

I'm sure I've seen a thermostat somewhere with a long (like a metre) fluid filled thin metal tube with a bulb on the end, which is the sensor.

"Capillary tube thermostat" in google turns up the sort of thing I'm thinking about, eg:

Or have a better idea for how to control this setup, that I haven't > thought of? :-)

>

[chris French]

In message , BigWallop writes

Doesn't sound particularly efficient to be heating up the space underneath the cupboards. Plinth heater sounds a good idea to me.

I have the kitchen heated just like any other room. The idea that you don't need so much heating because of the heat from the stove seems a bit out dated nowadays. Unless we are doing some baking, the cooker only really gets used much to cook dinner most days. And the kitchen is used for more that just cooking and washing up

We certainly do, most meals are eaten at the table, kids sit at the table doing crafts and stuff, I'll sit there with the laptop and a cuppa, or doing paperwork etc.

[The Natural Philosopher]

You only need an outsde stat with very long time costant stuff like UFH..where you need to anticipate a falling room temp befre it hppens, and start getting heat in..

For a kickspace, use a motorised valve to isoltate completely, or just switch the fan, and a normal stat in the kitchen.

[Dave Plowman (News)]

Weather compensated systems are rather more than just a stat with an outdoor sensor. They are a computer.

Seems to me it's the UFH that should be weather compensated with the additional heating being purely room temperature controlled.

[Dave Liquorice]

Agreed, and don't come cheap. I'd expect a UFH system to have that already though 'cause of long time they take to affect the room temp compared to ordinary rads.

Trouble is you then have it kicking in to heat the room when the UFH hasn't caught up. The OP only wanted the the auxillary heating to kick in when the UFH hasn't the capacity to maintain the room temp. Two different things but from the comfort point of view waiting for the UFH to catch up isn't very good...

[Dave Plowman (News)]

I thought UHF systems would be on 24/7 in the winter. But if not, a timeswitch on the auxilliary set to n minutes after the UFH comes on?

[Peter Taylor]

We have a Myson Kickspace in our kitchen connected into the ground floor radiator circuit, with power taken from the boiler supply so it is controlled by the programmer. The internal circuitry of the unit includes a thermostat to prevent it from blowing cold air but there's no upper cut-out, so I wired it in series with a roomstat to turn the fan off when the kitchen temperature is sufficient. This would fit your needs too I think. An external sensor is a refinement, but unless it controls the whole heating system you won't benefit by turning on the Kickspace early before the heating water heats up.

Thought about an electric one?

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