Heatline B24 not condensing is the condensing unit defective

[kayedee]

Boiler has been gradually condensing less and less, now not a drop, have checked the drain from the condensing unit heat exchanger sump and all is clear. (Flow temp well below 50 DegreesC)
Must be a problem with the hex unit, but what can possibly go wrong inside there? Anybody got knowlege of these boilers/condensing units, by the way it is called a 'Turbo Exchanger in the manual parts list.

 

[petertheplumber12]

I have a set of manuals and mine only list a C24 if so do you have lights that flash to give faults and what do they say, that looks like a very cheap boiler, that will give years of problems.

 

[kayedee]

Thanks for your reply ptp.

The B24 is the same as the Visio 24 except it has no internal time programmer.

These symptoms do not produce any fault indication, as boiler is functioning OK, just operating below efficiency.

Boiler was good value for money and no problems up till now (4yrs).

 

[ianmcd]

never came across a B24, before are you sure its not a C24

 

[kayedee]

Thanks for your reply ianmcd.
It could be one of the same, I no that it also appears as a Visio 24 which has a time programmer.
The B24 was sold under the Hydroline brand, B&Q were a large supplier.

 

[petertheplumber12]

I found the viso 24, and the burner pressure should be 12 mb when checked, it looks as if the burner is not going to full output, and without measuring pipe flow and return temps, etc it is very difficult to go much further, and I am sorry but value for money does not make anything good. The boiler has a secondary heat exchanger for condensing and that makes it of a lesser quality than a proper condensing boiler with a completely redesigned combustion chamber and fan. Your boiler WILL start to fail quicker than a more expensive one, but this it what you have so now I have got that of my chest, you need to get it checked by a gas safe person. Sorry.

 

[kayedee]

Thanks ptp,
Boiler pressure is 12mb, max output has been reduced to suit system load via potentiometer P4.
Boiler flow temp is at the setpoint set on temperature setting with delta t of roughly 20 degrees C, i.e flow 50 return 30.

 

[transam]

A vizo ? the secondary heat exchanger is so small about 3 loops of 12mm tube ?? I doubt it ever condensed much ?? at all

 

[petertheplumber12]

Now we know why no condensate, the reduced output, lower temp on flow means that the boiler is not now behaving as a condensing boiler, just using the primary combustion chamber to produce heat. that is why no condensate. also make sure that if condensate is run externally it is in 35mm waste pipe or 22mm white is insulated to stop it freezing. you now have a boiler that is normal efficiency about 65% instead of 85% - 90%

 

[ianmcd]

Kaydee you should be answering questions on here not asking them , you know what Delta T is and quote it ?? as flow 50 degC ret 30degC a boiler will never condense at these temps , do you have underfloor heating ? if not you must be bloody freezing

 

[D_Hailsham]

Flow 50 degC, ret 30degC; a boiler will never condense at these temps.

Never heard that one before! What temperature do you think think flow and return have to be for condensing to occur?

 

[Andygasman2010]

Now we know why no condensate, the reduced output, lower temp on flow means that the boiler is not now behaving as a condensing boiler, just using the primary combustion chamber to produce heat. that is why no condensate. also make sure that if condensate is run externally it is in 35mm waste pipe or 22mm white is insulated to stop it freezing. you now have a boiler that is normal efficiency about 65% instead of 85% - 90%

Sorry mate this aint right. Broadly speaking, lower temperature = more condensing.

 

[kayedee]

@Moderator 7

Is this pointed at me.
I am simply requesting forum knowledge on failure of condensing units in these boilers, as I have never seen inside one and am assuming it is a simple air to liquid hex, with 15mm pipe loops and heat transfer fins, I am trying to make contact with engineers that confirm this or advise otherwise.
Never any mention of DIY, but I am gas competent if that is what you want to hear for me to post this enquiry.

 

[Agile]

If you really are gas competent then you would be asking in the CC area of this site specifically for Gas Registered people.

If you are not Gas Safe registered then you are not deemed competent!

 

[kayedee]

If you really are gas competent then you would be asking in the CC area of this site specifically for Gas Registered people.

If you are not Gas Safe registered then you are not deemed competent!

I am now retired, therefore not registered.
That is not true, you have to be Gas Safe registered to carry out work on gas appliances and installation for reward, and have to be suitably qualified to apply.
Therefore you can be competent to work with gas, but may have changed career or retired.