Unvented cylinder

[busydad]

Morning all, got my boiler sorted last week and now finally decided to get the unvented cylinder.

My installer recommended a 200 litre tank and wonder if this is big enough? 2 adults and 2 children (who will grow up of course). 1 bathroom and 2 ensuites. At the min I shower in the morning and my wife in the evening and a small bath for the kids but thinking about the future. I assume reheat time is only 30mins or so anyway.

Also my installer is sticking with Telford Tempest as his recommendation. I can have a Gledhill but its about £220 more. I think its standing heat loss is about 23 watts better than the Telford. Just checking my maths but from a cost/efficiency point of view I would be better sticking with the Telford? 23 watts = approx 200kW per year?? at current gas prices about £6?

 

[Mottie]

There’s just the two of us at home and we both shower in the evening. We have a 150 litre cylinder and that’s plenty for us so I think 200 should be plenty for your needs. We don’t have the water temperature very high either as I think that if you have to add cold water to get the temperature down, you are heating water unnecessarily but when we have the kids stay over, I just turn the temp up a bit and we get more showers without running out of hot water.

 

[Dan Robinson]

We don’t have the water temperature very high either as I think that if you have to add cold water to get the temperature down, you are heating water unnecessarily

Oh dear

 

[Mottie]

Seems sensible to me.

This is what I’ve got coming out of my tap. Plenty hot enough for me. Any hotter and I’d need to add cold to it to get it down to the temperature I PREFER. Why the **** would I want to do that? Is it cheaper to heat water hotter than that nowadays?

 

[Dan Robinson]

Seems sensible to me

Seems bloody daft to me.

http://www.hse.gov.uk/legionnaires/

 

[Mottie]

Perhaps you should read stuff you post links to.

Identify and assess sources of risk
Carrying out a risk assessment is your responsibility. You may be competent to carry out the assessment yourself but, if not, you should call on help and advice from either within your own organisation or from outside sources, e.g. consultancies.

You or the person responsible for managing risks, need to understand your water systems, the equipment associated with the system such as pumps, heat exchangers, showers etc, and its constituent parts. Identify whether they are likely to create a risk from exposure to legionella, and whether:

• the water temperature in all or some parts of the system is between 20–45 °C

Now, have a look at my temperature (it had cooled down from 46.1 while I went and got my phone to take a picture) and tell me whether it is higher or lower than the recommended temperature that you sent me. Oh, it's higher! Guess I’m not so daft after all.

 

[Dan Robinson]

I do.

What is legionella?
Legionella bacteria is commonly found in water. The bacteria multiply where temperatures are between 20-45°C and nutrients are available. The bacteria are dormant below 20°C and do not survive above 60°C.

Legionnaires’ disease is a potentially fatal type of pneumonia, contracted by inhaling airborne water droplets containing viable Legionella bacteria. Such droplets can be created, for example, by: hot and cold water outlets; atomisers; wet air conditioning plant; and whirlpool or hydrotherapy baths.

Anyone can develop Legionnaires’ disease,

http://www.hse.gov.uk/healthservices/legionella.htm.

 

[Dan Robinson]

Perhaps you should try and comprehend what you're arguing about. Otherwise you'll just look like a prannet.

 

[Mottie]

I do.



http://www.hse.gov.uk/healthservices/legionella.htm.

Point taken. I’ve just had a proper read and cranked it up. Thanks and I apologise.

 

[Dan Robinson]

We don't make things up for fun you know

 

[Mottie]

Now up to this:



Bloody hot though - I can’t hold my hand under the tap now. I reckon 60° would take my skin off so I’m stopping at that.

 

[Dan Robinson]

That is a good thing. You will notice that your washing up will be easier now.

For reference, when I commission my cylinders, I tend to leave them at 55.