Help! - Noisy central heating system – not heating water well ……

[Garzie]

Hello !

I have recently moved into a new house – or rather a 1960s built house.

The central heating system looks to be around 10-12 years old

Its conventional mains gas boiler central heating system (not a combi)
the boiler is an “Ideal logic 18” –
with hot water tank in an upstairs airing cupboard - and header tanks in the loft above.

There is a single 3 way valve to direct the boiler circulation to the tank or the rads

Everything has been working fine - but I noticed when I teste it in the summer that the system was rather noisy when running either the rads or hot water – lots of whooshing water and gurgling noises. I bleed all the rad several times - and loads of air came out - but it didn’t seem to help much with the noises. The rads got hot and it heated water fine - so I thought maybe that just how it is.

However, the last few times I have used it to heat hot water - its not heating the water well - after 2 hrs the tank is still not fully hot - ie not hot enough for a full hot bath – when it defo was before.

So, things I have checked so far

• Boiler is firing – and displays no errors
• 3-way valve is changing position fine from all the way left when HW system is off - and all the way right when its on.
• CH pump is coming on and running -
• Pipes from boiler to HW tank are getting warm / hot

What’s not quite right / maybe

• The boiler comes on and fires – but the actual burner seems to shut down soon after – maybe after 30 seconds to 60 second – then sits that way for a few minutes - then cycles the same
• CH pump is also going off when this happens
• All the whooshing noises

Any ideas what could be up with it / what to check next

Where could all the air in the system be coming from and how come its not finding its way out when bled?

 

[Deleted member 120897]

Does sound like an airlock. Check the smaller of the 2 tanks in the loft for water?

 

[Garzie]

Does sound like an airlock. Check the smaller of the 2 tanks in the loft for water?

 

[Garzie]

Does sound like an airlock. Check the smaller of the 2 tanks in the loft for water?

thanks for your reply -

yeah - i wondered that - went up in the loft an checked last night - in case the expansion tank had run dry - but it had 3 to 4 inches of water in it and the ball cock was working fine

i bled the system only a few months ago - where could so much air be getting in ????

 

[Deleted member 120897]

Air can get in via a number of ways unfortunately, this might be why sealed systems are preferable, although can still get air in.

Examples of air getting in: undetected leak, micro air leaks, the vent pipe, hydrogen buildup in a sludged up system.

 

[Garzie]

Air can get in via a number of ways unfortunately, this might be why sealed systems are preferable, although can still get air in.

Examples of air getting in: undetected leak, micro air leaks, the vent pipe, hydrogen buildup in a sludged up system.

ok - understood - but how do i go about tracking down where its coming from ?

 

[tamzbackforalook]

Here is something for you to try since you are too miserable to pay a pro.
Take a glass of water up into the loft (well you can always scoop the water up there) and hold it with the expansion pipe dipped in and see what happens when you get the wife to turn the heating on.
Unfortunately i won't revisit here for ages but i'm sure someone else will provide an answer to you. Its not rocket science.
Btw i know exactly your problem but as i am persona non grata on here after years of educating people (i wish i had deleted the lot before they banned me) i'll let the smart asses who are left figure it out.

 

[Garzie]

Here is something for you to try since you are too miserable to pay a pro.

Wow! - Nice.
Actually the reason i am investigating this in the first instance is that i cannot afford to pay a "pro" at this point in my life.
Around 8 years ago i developed a chronic illness, lost my job,, spent 5 years almost house bound and am only now able to function at around 30% of my previous level, i am in considerable pain and unable to work.

Before this i was very fit and well, did lots of sports, had a good job, ate well, looked after myself - but these things can happen to anyone.
it could happen to you tomorrow....

 

[Garzie]

OK - so back on topic - i bled the rads again today and there was indeed a lot of air in most of the upstairs ones - no so much the downstairs ones.

the heating seems to be working fine. no loss of output as far as i can tell - is quiet apart from a bit of gurgling when it first starts - an doesn't seem to cycle on off like the HW was doing.

how can i track down why / how the air is getting in ?

 

[gmartine]

As suggested above make sure the system is properly dosed with inhibitor or you might be getting a hydrogen build up because of corrosion. Other than that the best way to prevent air ingress is to seal the system.