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Mar 24, 2021
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Scotland
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General Plumber
Unvented Cylinders sealed system -
I am looking to start doing more unvented heating installs having become well versed to fitting combis , my question is if you situated a unvented cylinder in a downstairs location with multiple appliances upstairs would the hot distribution pipe have adequate pressure or would a pump need to be fitted?
 
1. You can't fit unvented hot water cylinders without a G3 registration, which requires training and qualification. Without a current G3 registration (valid for 5 years):
1a. You cannot legally install the cylinders.
1b. You cannot undertake to self-certify the installation for Building Control.
1c. You cannot legally give them the annual service they require.
2. The training will cover the sort of question you are asking. However, given that the main purpose of an unvented hot water system is to provide hot water at mains pressure, it doesn't matter where the cylinder is fitted.
3. You would of course need to check the proper static, dynamic pressures and flow rates of the incoming mains. You might need to consider upgrading the internal cold water connection to the cylinder.
4. In an exceptionally tall building you might need to consider pressure loss with increased height.
 
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1. You can't fit unvented hot water cylinders without a G3 registration, which requires training and qualification. Without a current G3 registration (valid for 5 years):
1a. You cannot legally install the cylinders.
1b. You cannot undertake to self-certify the installation for Building Control.
1c. You cannot legally give them the annual service they require.
2. The training will cover the sort of question you are asking. However, given that the main purpose of an unvented hot water system is to provide hot water at mains pressure, it doesn't matter where the cylinder is fitted.
3. You would of course need to check the proper static, dynamic pressures and flow rates of the incoming mains. You might need to consider upgrading the internal cold water connection to the cylinder.
4. In an exceptionally tall building you might need to consider pressure loss with increased height.
Yes my next step is to get properly certified once colleges start reopening up again. I am yet to actively fit one I was curious about the hot supply. Thanks for the in depth reply.
 

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