Boiler water temperture

[Trevor Smith]

I have put on one of those clip on dial thermometers on the flow pipe from my old Mexico boiler and found that on the max setting the water temp was only getting to 62 degrees but the boiler manual states it should be 85 on max. Thinking that the stat was faulty I replaced it with a new one but the water temp was the same so what would be the reason for the low temp. I tried running the boiler with the thermostat phial removed from its pocket and stopped it when it got up to 75 so the boiler will get the water up to the temp but the stat seems to be stopping that happening.

[Artic]

Trevor Smith scribbled...

You want to get water at 85 out of the tap?

I believe the max temp of a hot tap is in the region of 50 degrees, any more and you risk burning a child or older persons skin very quickly.

[Baz]

Are you sure that the Thermometer is reading correctly ????

AND

Very difficult to get a good contact patch on tube.

Baz

[RobertL]

Those 'clip on' dial thermometers are not very accurate in my experience. The temperature reading seems to depend a lot on exactly how and where you clip it.

A useful rough check is that 60 Celcius is the temperature at which you can just about keep holding on but it feels very hot.

[Trevor Smith]

No I'm referring to the temperature of the water leaving the boiler, the ta nk stat is set at about 60 degrees so if the water leaving the boiler is al so 60 degrees then it will take longer to heat the tank taking in the loss of heat from boiler to tank pipework. The thermometer is on the flow pipe about two feet away from the boiler but I will try a different thermometer and see if it differs.

[harryagain]

Does it run all the time when the thermostat is set at max? If so, your boiler might be undersized. Or the pump may be running at too high a speed.

But quite likely your clip on thermomter is inaccurate, they often are. They have to make perferct contact too which is hard to achieve. Pipe has to be cleaned etc.

Or the boiler may need a cleanout/service.

By todays standards it is junk efficiencywise anyway. Get rid of it and save 25%.

[Mark]

I wouldn't. It will take quite some time to make any saving and, IMHO, modern boilers are less reliable. Keep it until it until you can't fix it.

[Vir Campestris]

No, it's elf and safety, you've got to have the water hot enough to burn or else people might get Legionella.

At least I assume that's the logic. I run mine cool.

Andy

[charles]

and having had it and, luckily, recovered, I wouldn't wish it on anybody

[Tony Bryer]

The two are not mutually exclusively. You store and distribute the water at a higher temperature and have a tempering valve next to the outlet.

[Onetap]

HSE recommendations are to store at 60 degC, and have 50 degC from any hot tap within 60 seconds of turning it on.

The users blend the water at the outlet (mixer taps or mix in the basin). If there are 'at risk' users (very young, very old, disabled, etc) TMVs should be fitted to all outlets. New builds require TMVs.

Those are for commercial buildings, the HSE aren't interested in private houses, the H&S at Work Acts don't apply. However the recommendations are sound, you can get legionella from household H&C water supplies.

It's a red herring in this thread though. The OP was asking about boiler (primary) flow temperatures and Artic misunderstood.

[Trevor Smith]

Following advice about clip on dial thermometers I got a K type wire thermo couple probe and meter and found that the temperature on the flow pipe abou t a meter from the boiler gets up to 80 degrees on max. I am quite happy wi th that just wished I had known that dial clip on thermometers were inaccur ate before buying a new boiler stat.