NTC Probes

[troublebrewing]

I have an ATC800+ and, although it doesn't say so this sensor on ebay looks like the identical beast.

Is that the same one that comes with an STC-1000?

[Dave S]

I have an ATC800+ and, although it doesn't say so this sensor on ebay looks like the identical beast.

Is that the same one that comes with an STC-1000?

Couldn't say, they're annoying secretive with part numbers etc.

[troublebrewing]

I've got dozens of them left over from where people buy the STC with a 3m sensor. I find it hard to believe they would be the same spec, but how can anyone tell? Certainly not at £17! The range seems similar, but without having a closer look later on... I'll do that.

[Blackaddler]

I have an ATC800+ and, although it doesn't say so this sensor on ebay looks like the identical beast.

Is that the same one that comes with an STC-1000?

The ATC800+ and the STC-1000 are manufactured by the same company, so the chances are that they source the probes from the same manufacturer.

The probes themselves are pretty simple. A length of twin wire, sheathed in plastic, with a solid state thermal resistor [thermistor], rated at 10000 Ohms [10k] and a Beta value of 3435, at the end.

Thermistors come in various sizes/values, but all look fairly similar...


They only cost a few pence, so should be cheap as chips.

[troublebrewing]

should be

Not always the same as 'are'.

[Blackaddler]

Very true.

[Blackaddler]

Well, I ordered the thermowell, and it arrived this morning.

Unfortunately, it has a ¾" BSP thread [DN15, whatever that is], and I've only got brass in ¾".

Any ideas where to source a stainless one?

Having consulted a heating engineer friend, he reckons it IS ½"BSP.

I don't know how you measure that, but across the threads it's about ¾".

This 1/2" BSP HEX LOCK NUT 316 STAINLESS STEEL 150LB should do the job, anyway

[Blackaddler]

The locknut arrived today.

It's stamped 316, but doesn't look top quality... it has a slightly rough looking finish to it, so probably Chinese as well.

However, it is the correct thread size, for the misol thermowell.

[Kev888]

Rather unhelpfully, BSP sizes refer to the nominal bore of the British Standard Pipe that the threads are used with, rather than the size of the threads themselves. Wikipedia has a useful table telling you their actual size here.

The other thing is that there are two flavours of the male thread: BSPT and BSPP - the last letter standing for tapered or parallel. If its a tapered thread check that the nut goes all the way up it; sometimes the male threads become too large a diameter at the fat end.

Cheers
Kev