That's how the efficiency figures for hot water are derived AFAIK.
Atag A325EC or Intergas Combi Compact HRE 36/30 ?
- Thread starter sadanorakman
- Start date
- Status
Sponsored Links
I asked them how they get their "default values" and this was the reply:
passed me your enquiry about the significance of the term ‘default value’ in the context of hot water energy efficiency in the PCDB.
The PCDB exists primarily to provide information for SAP assessors rather than as a product comparison system.
The assessment procedure includes domestic hot water. Therefore, all entries for combination boilers need to include a value for hot water energy efficiency.
However, the value included in an entry depends on the information submitted with the application for product listing. The provision of hot water energy efficiency data is not mandatory for submissions to PCDB.
The procedures used to determine the value entered in the database are those provided in Appendix D of the SAP 2012 document (http://www.bre.co.uk/filelibrary/SAP/2012/SAP-2012_9-92.pdf).
If no hot water data are submitted with an application the procedure in section D3.4 is applied to determine the value to be used in an entry. We refer to values derived using this procedure as ‘default values’. The procedure results in conservative values for hot water energy efficiency.
I hope that this answers your question.
...Interesting
passed me your enquiry about the significance of the term ‘default value’ in the context of hot water energy efficiency in the PCDB.
The PCDB exists primarily to provide information for SAP assessors rather than as a product comparison system.
The assessment procedure includes domestic hot water. Therefore, all entries for combination boilers need to include a value for hot water energy efficiency.
However, the value included in an entry depends on the information submitted with the application for product listing. The provision of hot water energy efficiency data is not mandatory for submissions to PCDB.
The procedures used to determine the value entered in the database are those provided in Appendix D of the SAP 2012 document (http://www.bre.co.uk/filelibrary/SAP/2012/SAP-2012_9-92.pdf).
If no hot water data are submitted with an application the procedure in section D3.4 is applied to determine the value to be used in an entry. We refer to values derived using this procedure as ‘default values’. The procedure results in conservative values for hot water energy efficiency.
I hope that this answers your question.
...Interesting
Just noticed Intergas and Atag have addressed the DHW efficiency figures and they show a dramatic improvement on the performance database
Sponsored Links
Guys,
I would be interested to know how your Atag combi's are performing in terms of domestic hot water performance i.e fluctuating temperatures at tap outlets and flow rates when other outlets are opened at the same time, especially when showering.
I've always dismissed combi's because of the above. I was planning a system boiler with an unvented cylinder but having measured my flow rate yesterday at 13-14 litres per minute it really falls in the combi range and the extra expense of the unvented cylinder may be uneccessary?
Regards
Mark
I would be interested to know how your Atag combi's are performing in terms of domestic hot water performance i.e fluctuating temperatures at tap outlets and flow rates when other outlets are opened at the same time, especially when showering.
I've always dismissed combi's because of the above. I was planning a system boiler with an unvented cylinder but having measured my flow rate yesterday at 13-14 litres per minute it really falls in the combi range and the extra expense of the unvented cylinder may be uneccessary?
Regards
Mark
And that figure is unlikely to be a dynamic flow rate!
After going through the boiler and a shower heat the flow is likely to be more like 8-10 li/min!
The useful measurement is the flow rate whilst leaving say 1.0 bar pressure in the pipework. You cannot guess this from an open pipe flow rate but is usually between 50% and 70%.
Tony
After going through the boiler and a shower heat the flow is likely to be more like 8-10 li/min!
The useful measurement is the flow rate whilst leaving say 1.0 bar pressure in the pipework. You cannot guess this from an open pipe flow rate but is usually between 50% and 70%.
Tony
The hot water of the Atag is great. We have 4 bar water pressure and I can turn the hot tap to its fullest and it will produce a very strong flow water that is too hot to touch! Our shower is also a good pressure. I'll test two outlets for you asap and let you know but the hot flow is so powerful I doubt it will be a problem. Hope this helps.
Measuring static and standing flow rates can be a right challenge. . It should also be done at peak hours
Yes it was nothing scientific. I just took a 1litre jug and timed how long it took to fill! Results will therefore I guess be mostly meaningless but here goes:
Hot tap only on full: 2 sec=30l/min of water too hot to touch- I think this is more than the stats for this boiler says.
5 sec shower only =12l/min
Both shower & tap on to produce a similar heat as before: 4 sec= 15l/min from hot tap
....oops looks like I forgot to measure the shower at this point but it was still useable, just a bit weaker. We have a thermostatic shower so temp was similar, just flow reduced.
Not sure this will help much in afraid.
Hot tap only on full: 2 sec=30l/min of water too hot to touch- I think this is more than the stats for this boiler says.
5 sec shower only =12l/min
Both shower & tap on to produce a similar heat as before: 4 sec= 15l/min from hot tap
....oops looks like I forgot to measure the shower at this point but it was still useable, just a bit weaker. We have a thermostatic shower so temp was similar, just flow reduced.
Not sure this will help much in afraid.
Thanks dmdm272,
I like the non scientific method and that 30 l/min is almost double what the manufacturer quotes, our potential installer recons that he has seen higher flow rates from the combi than what Atag quote.
Cheers
Mark
DIYnot Local
Staff member
If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.
Select the supplier or trade you require, enter your location to begin your search.
Are you a trade or supplier? You can create your listing free at DIYnot Local
- Status
Sponsored Links
