condensing range worth extra cost?

teach nua

I'm looking at installing a range cooker that will do the central heating and DHW and was wondering if its worth paying extra for a range with a condensing boiler for the extra efficiency. I'm deciding between the Stanley non condensing oil fired brandon 60 (60k btu output) and the Firebird condensing range which is supplied with the option of 50k/90k btu output. Firebird state that the burner can be supplied set to around 60k output. The firebird is approx. €1650 more expensive. The firebird is my only option for a condensing range as it needs to be fitted into an exisiting fireplace and it can be flued up a chimney. Stanley also do a condensing range but it has to be flued directly out through an external wall which is not an option for me

Given that the condensing range would be approx. 10% more efficient, is it worth the extra cost?

heinbloed

A condensing boiler makes only sense when the condensing modus is achieved, with a normal household boiler this condensing modus depends on the return temperature of the CH.

How high is the return temperature with the existing CH system?

JohnnieK

It would need to be installed with a fully controlled heating system to give you your money's worth. You wont make the saving back in a year or two it would be more like 6 to 8 years if you are going the whole hog with controls and that. If there is no controls then you would be looking at a lot longer.

You will have to compare your oil usage over a year and compare it with what was there before.
Any one that I have fitted the customers are saving oil so it must work.

teach nua

Heinbloed, I do not know the return temp. to boiler as don't have monitor for this. The exisiting boiler thermostat is set at it's lowest setting which i'm told is 60 C by manufacturer and it cuts in and out to maintain this temperature but i don't know what the return temp would be based on the thermostat's setting of 60.

Johnniek, the exisiting heating system is a 3 zone system with 2 heating zones and one for DHW controlled by a 3 channel digital clock and all rads are fitted with Thermostats. I agree with what you are saying about oil usage. If a condensing boiler is 10% more efficient and i'm currently using €1000 oil/yr that's a saving of €100/yr based on current oil prices so it would take me 16 years to make back the extra €1600 for the cost of the condensing range...or am I looking at it too bluntly?

Billy Bunting

You may also find you have higher service costs and very likely a shorter life span. :eek:

teach nua

teach nua wrote: »

. If a condensing boiler is 10% more efficient

You're system design will lose 3-5% of the 10% due to the higher system temperature of your type of heating system, you would have to have the system designed so the return temperature is low enough to allow the boiler to condense all the time otherwise it will only condenses on start up from cold.

heinbloed

If the flow temperature is set at 60 degrees Celsius and is kept there during the heating season (in cold winter time) then your existing system is propably very suitable for a condensing boiler.
The return temperature is usually about 20 degrees Celsius lower than the flow temperature - in a radiator system. So I assume with the given 60 degrees Celsius flow temperature a 40 degrees Celsius return temperature...

Meassure the real temperatures, a simple thermometer will cost around €5.- or an infrared thermometer around €50.-.

Is the meassured 60 degrees Celsius showing the flow or the return temperature?

About the installation of condensing boilers in existing chimneys:

The chimney must be corrosion proof, an extra liner (stainless steel, ceramic etc.) is usually necessary when retrofitting.Condensation will happen not only in the boiler but in the chimney as well, this condensate must be allowed to drain off. So a small diameter sewer pipe has to be installed somewhere near, allowing the condensate from boiler and chimney to be drained.
For a room sealed boiler (which most household condensing boilers are) an air supply pipe must be connected to the boiler as well. This is usually a twin pipe, a pipe-in-pipe system.

Before deciding on the purchase of a boiler check the manuals (installer manual and user manual !) and see what is involved.

heinbloed

heinbloed wrote: »

If the flow temperature is set at 60 degrees Celsius and is kept there during the heating season (in cold winter time) then your existing system is propably very suitable for a condensing boiler.
The return temperature is usually about 20 degrees Celsius lower than the flow temperature - in a radiator system. So I assume with the given 60 degrees Celsius flow temperature a 40 degrees Celsius return temperature...

Meassure the real temperatures, a simple thermometer will cost around €5.- or an infrared thermometer around €50.-.

Is the meassured 60 degrees Celsius showing the flow or the return temperature?

About the installation of condensing boilers in existing chimneys:

The chimney must be corrosion proof, an extra liner (stainless steel, ceramic etc.) is usually necessary when retrofitting.Condensation will happen not only in the boiler but in the chimney as well, this condensate must be allowed to drain off. So a small diameter sewer pipe has to be installed somewhere near, allowing the condensate from boiler and chimney to be drained.
For a room sealed boiler (which most household condensing boilers are) an air supply pipe must be connected to the boiler as well. This is usually a twin pipe, a pipe-in-pipe system.

Before deciding on the purchase of a boiler check the manuals (installer manual and user manual !) and see what is involved.

There is a bit of misunderstand in your post, how many heating systems have you set up? and how did you achieve your deltaT? when the system would be constantly altering as it's fitted with TRVs and zone valves changing the characteristics of the system, also would you be happy? that a boiler set to 60c will be able to heat a cylinder sufficiently to deal with Legionnaires, your advice about requirements for a condense pipe are wrong:eek: but you got reading the manual bit right:)

heinbloed

Reading the manual is very important, gary71. In a recent post it was stated that some installers don't do this.

Your post here for example, 18/2/2011 :

http://www.boards.ie/vbulletin/showthread.php?t=2056148524&page=3

as well as that of Billy Bunting, same thread and day.

The altering system is non-relevant, gary71, it is the boiler which has to be installed running safe and efficient in the OPs case.

The condensing boiler will keep the CH at a set temperature, if correctly sized. With very little fluctuation of temperature, only fluctuating within the precision of what the thermometers/thermostats work.

Of course a bad choice of materials and bad hygene practice will make any installation dangerous concerning bacteria and other consequences.

Legionnaires

are irrelevant, gary71. They propably don't fit into our pipes.
The bacterium which causes legionaires desease ('legionellas' is the common, non-medical term for these bacterias) is efficiently killed-off by chlorine, UV light and other meassures. The hygene of the heatexchanger is also guaranteed by the correct plumbing, for example not more than 150 liters of stored warm water (designed for humane consumption) in a standard household.
That's EU standard. No further meassures are needed, no heating (pasteurisation), no chlorination. Only an intelligent plumbing is needed, designed for intelligent consumers.
Storing hundreds of liters of warm water designed for human consumption will indeed cause problems.

What means that the standard Irish/British copper barrel with internal heat exchanger is obsolete, dangerous.We will teach that the amateur plumbers, if they bother to ask .....

This might be all new to you, so it would need a thread to answer the many questions you have.

I'm willing to help, others as well. So take the chance to learn something, ask your questions-one after the other- in separate threads.

You are more than welcome.

heinbloed

heinbloed wrote: »

The condensing boiler will keep the CH at a set temperature, if correctly sized. With very little fluctuation of temperature, only fluctuating within the precision of what the thermometers/thermostats work.

.

Have you ever commissioned a heating system? Very simple question:)

The type of system the OP has wouldn't condense for very long so the savings between condensing and non condensing are lessened making it less attractive to fit a condensing boiler, I base that on errr.... Commissioning boilers:P

heinbloed

Gary71 asks:

Have you ever commissioned a heating system?

Yes, more than one.

heinbloed

heinbloed wrote: »

, gary71. In a recent post it was stated that some installers don't do this.

Your post here for example, 18/2/2011 :

http://www.boards.ie/vbulletin/showthread.php?t=2056148524&page=3

I am more than happy for you to chuck up my posts and for you to think you know more about a trade I'v been struggling to get my head round for 25 years, your ignorance to my trade is not a problem for me as you don't actually fit heating systems so what damage can you do:).

heinbloed wrote: »

I'm willing to help, others as well. So take the chance to learn something, ask your questions-one after the other- in separate threads.

You are more than welcome.

you may feel you know it all:pac::pac: which is fine, but if you were actually qualified to do the things you post about, you would find out why I can't take you seriously, that's my qualified opinion .

heinbloed

heinbloed wrote: »

Gary71 asks:



Yes, more than one.

:eek:

heinbloed

heinbloed wrote: »

Gary71 asks:



Yes, more than one.

O.k then you would understand that setting up the delta T you would need the heat load to stay constant and if it reduces in size it allows more heat to go back down the return, bearing in mind most oil boilers don't modulate.


I still can't take you seriously :P