Please explain how my electric underfloor heating works!

[D_Hailsham]

... our gas is ... imported (or derived from coal in coke-making plants).

Are you saying that some of our power stations still use Coal Gas (aka Town Gas), not Natural Gas?

I would be interested to know which ones.

No, it was a reference to back in the 60's 70's a lot (nearly all ?) of the gas used in homes came from coke ovens.

I assumed that when you said 'our gas is imported (or derived..)' you were taking about the present day.

Prior to 1967 all homes used coal gas. The change over to natural gas took about 10 years.

 

[SimonH2]

My knowlage of UFH is purely from the fact its what my parents have in there house, built in the later 80's when I was a kid. They have around 13kW of elec UFH, split over 10 circuits (most rooms have a small and a large circuit) , with a single relay running of a manual timer which they adjust based on demand.

Well 13kW is well over 50A, and it sounds like you possibly didn't have individual room stats - so a relay would have been necessary since there aren't that many timers (with a sensible WAF !) suited for that sort of load.

Its not the cheapest option, but given they are not on mains gas, its not hediously much more then oil, and means they dont have to have a boiler or have the heating replaced.

That's another factor. If you aren't on mains gas then the alternatives cost "somewhat more". Where i used to live we didn't have mains gas. At one point the gas people offered to connect the village up, but few wanted to pay the connection fees they were talking about. It did happen eventually, but not while we still lived there - and no, don't read anything into that

I assumed that when you said 'our gas is imported (or derived..)' you were taking about the present day.

Ah, easy to case a tense wrong

Prior to 1967 all homes used coal gas. The change over to natural gas took about 10 years.

That would tie in with what I remember. I recall one of our physics teachers at school complaining that some of their experiments/demonstrations didn't work the same with this "new natural gas".

 

[dhutch]

Well 13kW is well over 50A, and it sounds like you possibly didn't have individual room stats - so a relay would have been necessary since there aren't that many timers (with a sensible WAF !) suited for that sort of load.

Indeed, there are no room stats, infact there are no stats at all.

Google suggests WAF in an acronym for 'wife acceptance factor' which doesnt really come into it as mum is pretty good on things like that, but equally, its all in a cupboard. The biggest WAF improment was when 20yrs in the relay was replaced with at twin coil one which is much quieter holding in the contacts.


Daniel

 

[SimonH2]

Ah yes, relay hum (or buzz) can be a real problem. There are some specialised relays that run the coil on DC (from an AC supply) to get around that.

 

[dhutch]

Ah yes, relay hum (or buzz) can be a real problem. There are some specialised relays that run the coil on DC (from an AC supply) to get around that.

Yeah I think this one does that, big ac coil to throw it in, smaller dc one to hold it.