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Central Heating

Boiler not as efficient

My boiler is 6yrs old its a condenser combined. When my heating is on if I put all 4 rads on upstairs with flow limited I can't get two on at all downstairs out the total being six. Also when heating on very difficult to get a constant flow of hor water from bath tap. Bathroom sink OK though? I followed instructions and got air from rads upstairs only. But hasn't made any difference. There is a very slight leak from boiler some days nothing other days about a teaspoon full. Pressure is fine. Its a sealed system and I did add some water back in after bleeding the rads which brought it back up to one and a half. Could it need a new pump? Flushing out? Are these jobs expensive? Boiler is a he at line c24 model. In its second yr was loosing pressure and had what looks a fire extinguisher attached. Please someone advise on problem and costs. Kind regards


Thank you for your reply. I haven't made myself clear sorry . I have four rads upstairs and six downstairs. Total ten. I was looking at new rads in wickes that state there double rads use less water would they help? Downstairs two are old ones both double built like tanks. So thinking of changing them to new ones. What would be best single or double considering there are 10 in system. Im thinking smaller rad gives more chance of all working more efficiently. Is this right? There is two old rads upstairs which are singles the other two are new. When I got new boiler I had four new ones added two small ones replaced one large one in living room one added in conservatory. Hence the mix match of old and new. Would really some answers advice.

Kind regards.

2 Answers from MyBuilder Heating Engineers

Best Answer


I'm afraid it is very difficult to diagnose without Inspecting the system. If you are unable to run hot water during a CH demand I would initially be questioning the diverter valve. Hot water should always take priority with a combi boiler. Being unable to heat only 6 rads from a 24kw boiler leads me to think the system is possibly incorrectly balanced - There are a number of factors which could be causing these problems. Im sorry this is not a definitive answer but it is almost impossible to diagnose such a fault without inspecting the boiler.

With the added information I would say the boiler is slightly undersized (not quite man enough for the job) especially considering the mix match of old/new. There is a strong possibility that there is dirt/sludge in the system causing issues with circulation and this wont be helping. Again please do not take this as gospel because it is very easy to guess at the issues sat infront of the computer but without checking system water / pump etc it is just an educated guess. I would be looking at adding system cleaner and allowing to run for a week or 2. followed by a flush and add inhibitor along with a full system balance. Another tip is to shut all working rads off (on the TRV) to try and push some circulation to the rads that arent heating. If this works, slowly open the other radiators back up until they are reaching a satisfactory temperature.

Otherwise I would recommend arranging a visit to try and diagnose the cause of the issues you are experiencing. I hate to say it but GAS ACES has pretty much hit the nail on the head - Heatline boilers are not regarded as the most reliable within the industry.



Answered 28th Jan 2015

I'm sorry to say that, but for some Heatline boilers 6 years is end of life. They cost half of decent boiler and survive equally shorter time.


Answered 27th Jan 2015

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