Boiler Question

16
Found 10th Jul
Would it be OK to install a combi boiler with hot water flow rate of 16.4l/min at 35C when I only have 15l/min at the boiler location.


Is there any minimum flow rate requirement? I haven't seen anything on the datasheet.

I would like to have the maximum flow rate possible with 10 years warranty. My best option price/warranty is the Ideal Vogue 2 40kw. I don't see any other boiler which has 10 years warranty and good hot water flow rate.
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That would not be a problem - you would not necessarily open the hot water tap(s) fully on every use - so no need for maximum flow on every occasion. There will most likely be a minimum flow switch in the boiler which will need to be satisfied before the boiler will fire.

Can't comment on boiler make as I don't have a combi myself. On something like a 10 year warranty consider what the terms are - are you fixed to how often and who has to service the boiler? What are the costs of a service compared to an annual cover agreement?

Hope your renovations are going well!
Adding to the above does the warranty include parts AND labour? Call out charges etc. Read the terms carefully
Van19738 h, 5 m ago

That would not be a problem - you would not necessarily open the hot water …That would not be a problem - you would not necessarily open the hot water tap(s) fully on every use - so no need for maximum flow on every occasion. There will most likely be a minimum flow switch in the boiler which will need to be satisfied before the boiler will fire.Can't comment on boiler make as I don't have a combi myself. On something like a 10 year warranty consider what the terms are - are you fixed to how often and who has to service the boiler? What are the costs of a service compared to an annual cover agreement?Hope your renovations are going well!



Thanks Guys!

Good news! I have discovered that the taps were restricting the flow. My flow rate is over 17.5l/min

Now I need help with the central heating output.

In the specs say the minimum CH output is 5.7KW/h and maximum 32KW/h (Modulation 7:1)
All my radiators together have an output of 7.1KW/h.

Will it cause the boiler to cycle ON/OFF too often? I am bit worry about being close to the minimum CH output. I don't think I will have very often the CH on full and all the TRV valves fully opened.
Edited by: "daniq" 10th Jul
adhkarzf6 h, 56 m ago

Adding to the above does the warranty include parts AND labour? Call out …Adding to the above does the warranty include parts AND labour? Call out charges etc. Read the terms carefully


The warranty seems pretty good. Labour and Parts for 10 years when their filter is installed.

idealboilers.com/upl…pdf
34308309-ptg88.jpg
daniq15 h, 52 m ago

Thanks Guys!Good news! I have discovered that the taps were restricting …Thanks Guys!Good news! I have discovered that the taps were restricting the flow. My flow rate is over 17.5l/minNow I need help with the central heating output.In the specs say the minimum CH output is 5.7KW/h and maximum 32KW/h (Modulation 7:1)All my radiators together have an output of 7.1KW/h.Will it cause the boiler to cycle ON/OFF too often? I am bit worry about being close to the minimum CH output. I don't think I will have very often the CH on full and all the TRV valves fully opened.


Did you not ask the same questions 2 weeks ago? Yes the boiler will cycle constantly wasting gas and putting extra wear and tear on the boiler, the boliers you’ve shown interest in are too big for your application and any one prepared to fit one for you should be questioned on it.

What has your gas fitter said about it? Did you do a heat loss calculation for your house or just going off existing radiator sizes, also how did you work out the output from your existing radiators?.
paulj4831 m ago

Did you not ask the same questions 2 weeks ago? Yes the boiler will cycle …Did you not ask the same questions 2 weeks ago? Yes the boiler will cycle constantly wasting gas and putting extra wear and tear on the boiler, the boliers you’ve shown interest in are too big for your application and any one prepared to fit one for you should be questioned on it.What has your gas fitter said about it? Did you do a heat loss calculation for your house or just going off existing radiator sizes, also how did you work out the output from your existing radiators?.




I have had 4 gas engineer giving me quotes and they haven't done any heat loss calculation.

I worked out the BTU of all my radiators by checking the BTU output on the Stelrad catalogue.

The modulation on this boiler is 7:1. Most Worcester are 4:1. That means the minimum heating output of a Worcester 25KW is similar to the Vogue 2.
So I am confused about boiler cycling ON/OF. Wouldn't be the same with any other boiler, or would I have to go to a very expensive combi with wider modulation?
if the minimum output of the boiler is below the maximum output of your radiators you've got nothing to worry about.

yes boilers cycle on and off to maintain temperature and the effect on lifecycle is likely to be minimal considering other parts will break first
adamspencer9511th Jul

if the minimum output of the boiler is below the maximum output of your …if the minimum output of the boiler is below the maximum output of your radiators you've got nothing to worry about.yes boilers cycle on and off to maintain temperature and the effect on lifecycle is likely to be minimal considering other parts will break first


Thank you Adam. Do you work with boilers? It is seems like you know what you are talking.
daniq6 m ago

Thank you Adam. Do you work with boilers? It is seems like you know what …Thank you Adam. Do you work with boilers? It is seems like you know what you are talking.


hardly say I'm an expert

it's not that difficult with regards to specifying a system as they all generally function in the same way.

as above, you want to try and get as close to your requirement as possible when specifying a boiler, but overspec'ing is always a better option than cutting it fine.

I couldnt fit one to save my life, though
adamspencer957 m ago

hardly say I'm an expert it's not that difficult with regards to …hardly say I'm an expert it's not that difficult with regards to specifying a system as they all generally function in the same way. as above, you want to try and get as close to your requirement as possible when specifying a boiler, but overspec'ing is always a better option than cutting it fine. I couldnt fit one to save my life, though


Thank you Adam.

What do you think about the ideal Vogue 2 40kw for an ex-council house with 3 bedroom, very large windows and external insulation?

I have been quoted £2300
adamspencer951 h, 1 m ago

as above, you want to try and get as close to your requirement as possible …as above, you want to try and get as close to your requirement as possible when specifying a boiler, but overspec'ing is always a better option than cutting it fine.


Whoever told you it’s better to over spec a boiler needs to go back to college
paulj4816 m ago

Whoever told you it’s better to over spec a boiler needs to go back to c …Whoever told you it’s better to over spec a boiler needs to go back to college


Do you think with the information provided a Vogue 2 40kw is a bad choice? over spec?
paulj4853 m ago

Whoever told you it’s better to over spec a boiler needs to go back to c …Whoever told you it’s better to over spec a boiler needs to go back to college


if you had read correctly i said its better to over spec than under, or did you miss the part where i said its best to be as close as possible to the expected usage?

i think a 32kW model would be more suited to the OPs situation, unless there is a need for multiple uses of hot water in the house at once.
Honestly these are questions you should be asking the plumber you have providing the quotes.

iirc the closer to the maximum rating of the boiler the better the efficiency.
If your looking at Ideal then look into Baxi. Generally they are very similarly priced, warranty, spec, etc.
joedastudd16 m ago

.iirc the closer to the maximum rating of the boiler the better the ….iirc the closer to the maximum rating of the boiler the better the efficiency.


Agreed, Op take notice
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