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Davidfilce  
#1 Posted : 23 August 2022 09:46:33(UTC)
Rank: Forum user
Davidfilce

Hi

Is there any guidance to estimate the temperature of hot water within a cylinder / calorifier by taking the temperature of the tank casing?

If the tank casing is, say 55 degrees, what temp is the water within likely to be inside?

I would imagine there will be a drop in temp (the water being higher than the tank casing) but of how many degrees, I don't know.

If there is a reliable source I can cite, that would be even better

Thanks in advance

David

Tstamps  
#2 Posted : 23 August 2022 12:55:17(UTC)
Rank: New forum user
Tstamps

Hi David

Try here - https://www.hse.gov.uk/pubns/books/l8.htm

I believe that you are supposed to check the nearest point to the calorifier, ie the piping from the calorifier to the Sentinel outlet. Use a contact thermometer, if i remember rightly the readings should be 60 degrees as they leave the unit.

Regards

Davidfilce  
#3 Posted : 23 August 2022 13:01:10(UTC)
Rank: Forum user
Davidfilce

Thank you.

I have used a contact thermometer at the outlet, but there will be a difference between that temperature and the temperature of the heated water.

There will be a correction value, albeit 1 or 2 degrees, perhaps more, between the contact temp and the actual water temp

Regards

David

Kate  
#4 Posted : 23 August 2022 14:52:14(UTC)
Rank: Super forum user
Kate

I don't see that it would be as simple as a correction value.  The difference between the temperature of the water and the temperature of the outside would presumably depend on several factors such as the air temperature and ventilation.

thanks 1 user thanked Kate for this useful post.
Roundtuit on 24/08/2022(UTC)
Tstamps  
#5 Posted : 23 August 2022 15:50:13(UTC)
Rank: New forum user
Tstamps

If you take the reading at the earliest possible point of its exit from the calorifier, then you have a pretty accurate reading of the tanks contents. The variances over this small distance would be almost insginificant i believe.  I literally take the reading by contact with the outlfow pipe as it leaves the tank. 

I dot think there is an easier way to get a more accurate reading which is i believe the temperature for calorifier is set slightly higher than at outlets.

Xavier123  
#6 Posted : 24 August 2022 09:48:13(UTC)
Rank: Super forum user
Xavier123

Imagine the thermal energy loss on hot water tank casing itself that has an external temp almost matching its contents! 

You're right that the contact temp on a pipe etc. is not likely to be a direct measurement of the water temp but that's quite different to a tank which is presumably insulated etc. to minimise heat loss. With that in mind, you're unlikely to find a reliable correction factor for this. With some experimentation at a local level you might be able to match up tank contact values routinely with flow values I guess?

But if I was measuring 59 degrees on my pipe outflow temp, I wouldn't be stressing too much about proving it was actually 60 inside. Most legionella bacteria would just perish slightly slower even if it was accurate.

thanks 1 user thanked Xavier123 for this useful post.
Roundtuit on 24/08/2022(UTC)
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