Running co-ax

Jack Harry Teesdale laid this down on his screen :

I have had multiple coax and LAN cables, sharing a duct, unclipped and no doubt in contact with my heating pipes for the past 40 years. I have had zero issues and do not expect any.

That is indeed the question. But the fact remains that the thermometer does go up to 120C.

It's no like a car where they may fit an over-optimistic speedometer that far exceeds any possible speed of the car, which the driver could never legally attain in most jurisdictions in any case.

So why up to 120C ?

michael adams

...

"This pipe temperature gauge can be used on domestic and industrial pipes"

I can think of industrial uses where the temperature of what is in the pipe exceeds that of a domestic water or CH supply.

tim... formulated on Saturday :

Lots more is possible, but some breach copyright.

Look up Troypoint.

So you?re taking the relief pressure valve setting in boilers as an indication of typical CH water temperature?

Tim

Not in a typical domestic CH system.

Tim

Because you might want to clip them onto a pipe that *isn?t* in a normal CH system?

Conceivably a fault condition could cause the temperature to go that high in a pressurised system but that is a long way from normal operating temperature.

Tim

Why not a more than adequate scale range? As you yourself agreed, car speedos go well beyond the possible maximum. My speedo ranges to

I wonder if for both the pipe thermometer and a car speedo, the gauge is calibrated beyond what is ever achievable because the gauge becomes less accurate as it reaches full-scale deflection and so they arrange that the highest achievable is some way short of FSD. Only a theory - and I'm probably wrong.

Even if water at 3 bar would boil at 120 degC, I doubt whether anyone would set their boiler for that sort of temperature (60 is more typicial) because any contact with a pipe at 120 would cause a nasty burn. I've always wondered why it is that 50 degC shade temperature (eg in Death Valley) is something that the human body cannot tolerate for more than a few minutes, and yet saunas can (apparently) have a room temperature of almost 100 degC. I know saunas are very dry heat but so is Death Valley.

Of course not. I am pointing out that, potentially, that's the temperature the water could reach if there was a double failure in the boiler control system.

I'm also making the point that it is not *so* unreasonable to have a pipework thermometer capable of going up to 120 deg C.

I never said it wasn?t. Just pointing out that just because a pipe thermometer reads up to 120, it?s in no way a typical CH pipe temperature.

Tim

Oh agreed. But nonetheless >100C will be the boiling point.

IMHO it will be fine.

Typically PVC clad cables are specified for a maximum continuos conductor[1] temperature of 70 deg C. Beyond that, you may start to see some gradual degradation of the plastic - (typically it becoming more brittle as it loses plasticiser) - but at only a little over than you can expect it to take decades.

A CH pipe will probably be less than 70 degrees anyway, and even if not it will not be continuously at that temp.

The PRV is normally just that, not an Over Temp & Pressure Release Valve. However the bailer's main internal stat will typically kick in well before boiling point.

(and remember the flue on most modern boilers has a plastic inner!)

Just because an Amazon seller calls it a "Clip On Hot Water Pipe Thermometer", does not mean it was *designed* only for hot water pipes.

It might find service on steam pipe or oil pipe.

(and the thermometer is not going to know or care what is in the pipe!)

Possibly it's intended to cope with pressurised steam pipes. They really burn if you touch them. Or it might be a basic design also used for other products, such as asphalt thermometers.

Bill

What does it matter? What does it f****ng matter?

I'll expand on what I said before. I started installing TV aerials as a full time job in 1971, after working part time for five years. Over the following five decades my business expanded to include domestic and commercial satellite reception, CCTV, private mobile radio, broadcast radio transmission aerials, and very large RF distribution systems. In all that time, with that wealth of practical experience, I never once, never ever, not once, ever, encountered a length of coax that had been adversely affected by being in contact with a hot pipe. So does that put your mind at rest?

Bill

Yes, coax becomes more flexible on hot days, and can be a stiff nightmare in winter.

But my goodness it would have to get damned hot to let the inner migrate. It would be easy enough to test. Put some coax into a tight bend and boil it in water for a few hours. I've never done this, but I can tell you that black coax on a south facing wall on a hot day gets too hot to touch (I've been burnt) and yet it continues to work.

Bill

The heat cannot be 'radiated at 120C' whatever that means, when the water temperature never exceeds 60 °C.

Someone should to a study on the correlation between Left thinking and inability to understand any science at all.