Condensing Mode

[plumbarius]

Hello All, A simple question How Do You Know When A Boiler Is Condensing? I am quite aware the Return Temp. should be 55c or less, Mine often is but still seems to steam a lot, with modern technology I would have thought it would tell you on the boiler display when it`s condensing,
Thanks Alex.

 

[Dan Robinson]

It's not steam. Well not in the sense you might be thinking.

 

[mehran]

its a bit more complex then a simple 55c or less statement.

its not a switch were all the water vapor will suddenly condense. the point will change with % co2/excess air.

also it not really the return temp that is key. its the temp of flue gas that matters....

to cut a long story short we say 55c or less to make it simple. the father below 55c the better. the reasons they dont tell you loads of info on the front of the boiler is the end user would not really understand and they don't care.

 

[mickyg]

the reasons they dont tell you loads of info on the front of the boiler is the end user would not really understand and they don't care.

and we would also realise super dooper boilers weren't so super dooper

 

[Agile]

You can get a good idea of how much its condensing by measuring the flow rate perh hour of the condensate ( if any ).

Tony

 

[bolshy]

Cold weather = steam plume from a condensing boiler. You can't condense all the vapour.

 

[ianmcd]

You can get a good idea of how much its condensing by measuring the flow rate perh hour of the condensate ( if any ).

Tony

So what does that tell you Tony apart from how much condensate is being produced ?

 

[Agile]

Hello All,

A simple question How Do You Know When A Boiler Is Condensing?

Thanks Alex.

Ian, measuring the flow rate of condensate answers the OP's question of how he can know that the boiler is condensing!

Of course it was a very simple question and that gives a simple answer!

He would get a better idea of the likely efficiency by measuring the flow and return temperatures at the boiler but he did not ask about that!

Tony

 

[gaswizzard]

Reduce O2% and condensate trap will run like a tap.

 

[ALEC1]

best way to make a boiler condense more is to lower the flow temp, which lowers the return temp..modulating controls do this automatically, to ensure that the flow temp is as high as it needs to be to maintain comfort levels...

 

[Corgigrouch]

best way to make a boiler condense more is to lower the flow temp, which lowers the return temp..modulating controls do this automatically, to ensure that the flow temp is as high as it needs to be to maintain comfort levels...

But then that means that there is a good chance that you will need to increase the size of the radiators (Assuming radiators are fitted) and when you tell the customer about a house full of new radiators they look at you as if you have just grown three heads....And then they place the order with the guy who has priced them for just a new boiler...

 

[ALEC1]

no thats not the case at all.. the flow temperature varies according to the heat needed, so if there is a big difference between room temperature and programmed temperature then the radiators are run at maximum temp and if there is a small temperature difference the radiators are cooler...

 

[David937]

no thats not the case at all.. the flow temperature varies according to the heat needed, so if there is a big difference between room temperature and programmed temperature then the radiators are run at maximum temp and if there is a small temperature difference the radiators are cooler...

Yes but I think the point he was trying to make is you need to oversize radiators a bit so the flow temperature can be run at as a low temperature as possible except in extreme weather. This increases the price which usually means you lose the work!

 

[ALEC1]

again not the case at all..

radiators are always oversized at anything above outside design temperature, usually -3c..


and modulating controls tend to run the pump and burner at lower temperatures, switching it off to lower the flow temp if need be, for longer..

 

[ianmcd]

I think that everyone is getting too technical on this one , as I read it the OP thinks that as his flue is pluming then it is not condensing, OP that is not the case in this cold weather you will most always see "steam" as you call it from your flue does not mean anything is wrong with the boilers operation