Central heating problems!

apnet · 8 Mar 2010

Boiler: Ariston Combi A 30 MFFI (just over 2 years old)

I am looking for some advise on my central heating. None of the radiators work 100%.

Last weekend I did a manual flush, removed all the radiators and washed them with a hose. I then added x800 (without powerflush machine), I left this to run in the system from around 16 hours with all radiators open to maximum. I noticed all the radiator were very hot. After wards I flushed the system clean, installed a MegnaClean and refilled the system with x100 inhibitor added.

The system initially ran great. But today I am back to square one, the heating has to run for about an hour before the radiators are even lukewarm. The hot water works great, there is no boiler noise.

Can anybody please suggest what my issue could be? Is there something wrong with my boiler?

Andygasman2010 · 8 Mar 2010

That's really odd, considering it worked ok the dipped off. Maybe there's some kind of pump issue. Try it from cold, does the boiler get really hot really quick? Then cycle like this until rads are warm? This might be one a heating engineer needs to have a look at.

crockett · 8 Mar 2010

There may still be an airlock somewhere. Have you tried releasing any air from the bleed valve on the boiler and / or the pump ?

darren17 · 8 Mar 2010

did you pressurise the system
have you tried to bleed the pump
did you open the iso valves on the magna clean unit

JohnD · 8 Mar 2010

how full is the Magnaclean?

Did you rebalance the rads?

apnet · 9 Mar 2010

Random things are happening, the radiators that were not coming on last night were hot thing morning and the ones that were hot last night are cold!!!!

If I release water from a cold radiator while the heating is on, the radiator warms up.

I have released the air from all the radiators, I cannot find a bleed valve on the boiler itself. The meganclean valves are also open and it is full of water.

I have not really balanced the radiators as this was not done originally.

I did not bleed the pump, I'll try this tonight.

JohnD · 9 Mar 2010

how much sludge did you scrape off the magnet sleeve?

JohnD · 9 Mar 2010

you said that (1) you have not balanced the system and (2) some of the rads are hot and some are cold. This is typical of a system that needs balancing. This means that the hot water circulated by the pump is travelling through a few rads, making them hot, and none of it is taking an alternative route through the other rads (perhaps the pipes are longer or the route is more arduous)i

For a quick fix, turn off the hot rads, then open their valve half a turn (it only needs to be open enough for the pipe to get hot - this is surprisingly little). If some of the rads are still cold, do the same to the ones which are now the hottest. If you have TRVs then you will have to do it by adjusting the lockshields, otherwise nothing will happen until the rooms with the hot rads are fully heated.

To do it properly, //www.diynot.com/wiki/plumbing:faq:faq2

If, like most of us, you have not got pipe thermometers or an infra-red heat sensing gun, the flow pipe should be "too hot to hold" and the return pipe should be "too hot to hold for long"

apnet · 15 Mar 2010

Thanks JohnD, your post helped a lot. I balanced all the radiators and everything kicked into life.

BUT, I did this when the heat turned to max (80) and the boiler set to continuous operation. Now when the heat turned down to just over midway (65) and the boiler running on 'auto' I notice the radiators are nowhere near as hot. Continuous operation seems to be the key, but obviously I can't leave it on this setting.

JohnD said:
you said that (1) you have not balanced the system and (2) some of the rads are hot and some are cold. This is typical of a system that needs balancing. This means that the hot water circulated by the pump is travelling through a few rads, making them hot, and none of it is taking an alternative route through the other rads (perhaps the pipes are longer or the route is more arduous)i

For a quick fix, turn off the hot rads, then open their valve half a turn (it only needs to be open enough for the pipe to get hot - this is surprisingly little). If some of the rads are still cold, do the same to the ones which are now the hottest. If you have TRVs then you will have to do it by adjusting the lockshields, otherwise nothing will happen until the rooms with the hot rads are fully heated.

To do it properly, //www.diynot.com/wiki/plumbing:faq:faq2

If, like most of us, you have not got pipe thermometers or an infra-red heat sensing gun, the flow pipe should be "too hot to hold" and the return pipe should be "too hot to hold for long"

Agile · 16 Mar 2010

Just to help me understand what you did wrong, when you removed the rads to take them off, did you alter the rad valve settings?

Tony

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Central heating problems!

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