Voltage free contacts

Volt Free or "Dry" contacts are just like a normal power relay - they have a coil & contacts (switch) that open & close when the coil is energized & de-energized.

The difference is they have a separate low voltage supply to control the relay coil & make/break the mains voltage power contacts that switch (e.g.) motor or heater in your case.

The "volt free" coil power is actually low voltage,  typically 24v to 48v AC/DC.  The idea is to keep mains volts separate from sensitive electronic control circuits.  

Do they pollute mains & affect SQ, ??   I don't know, but I suspect if the low voltage is supplied from a SMPS, then they will get blamed for it whatever.

Chris

Does the bathroom heater have the facility to be switched on with a VFC, usually something so simple wouldn’t.  Does it even the have facility to be switched by 240v.  How is the heater powered and switched at present.

With regards to digital display versus mechanical, the digital display option will probably give you the facility to set different on/off times for each day of the week.

Does the heater have temperature control, if not consider something like a Drayton Digistat 2, this will provide temperature and time control.

The "voltage free contact" is a bit irrelevant to the original question.

All voltage free contact means is that there are an additional set of switching contacts that operate in parallel to the main load switching. These are just presented externally to the contactor and not connected to the mains supply. They are available for auxiliary switching. For example a low voltage indicator that shows when the heater is on.

Chris

Hopefully won't become too distracted by the misinformation.

"without VFC" will have 240v output. This is used to switch equipment that requires 240v to switch.

"with VFC" does not have any voltage output, the voltage is generated in the equipment being switched. The timer open and closes the circuit, this circuit isn't necessarily low voltage, it could be 240v.

Before you go any further you need to determine if your heater can be switched and if it can does it require 240v live or VFC to switch..

It may take both, my combi boiler can be switched by 240v live or VFC (24v DC circuit)

Thanks guys, I guess the non-VFC version is going to be fine, and I'm probably worrying about nothing. The heater is just a 600W bathroom towel rail/radiator with no other controls. 

For a towel rail, I'd personally go for something with a boost button. In the summer or whenever it's not required to heat the room, you'd be able to dry towels by hitting the boost button which would turn it on for an hour.

Spending more money on better controls will pay for itself in the long run. Given the price of electricity it won't take to long.

I take your point, but when you live in an old house at 1000' above sea level on a N facing hillside, it's a struggle to prevent your house from being enveloped in a mass of black mould. I find a more or less constant, low level of heat to be the best way to keep this under control.

My original point, though, was that I wanted reassurance that a timer wouldn't affect the sound quality of my Naim gear by polluting the mains. The fact that we've been booted into Padded Cell is, presumably, because we've drifted onto the subject of bathroom heaters!