Major problem with air in system

[Bob1985]

Hi - hope someone can help.

We had a new boiler installed a few weeks ago, since then we have had a major problem with air in the system, The system needs bleeding 2-3 times a day.

To cut a long story short, I do not trust the company to put it right because to be honest they seem incompetent. On the day of install the plumber cut the gas pipe instead of the water pipe, they forgot to turn the mains back on to the header tank resulting in the boiler shutting down 5 days later, I would prefer to resolve the issue myself, if I can.


I'm not that up on plumbing but know the basics so I will try and explain my situation.

We can bleed the system (heating/pump off) but then within a couple of hours we can here the radiators gurgling, if I stand by the header tank/boiler when it's running there is a noise coming from the expansion pipe, it just sounds like water boiling and splattering.

I have checked the pipework where I can and there are no leaks, I have tried the pump on setting number 1, no change, it's set on number 2, the pump is situated at the base of the boiler/right hand side in a vertical position, then the pipework then goes all the way to the top of the boiler, I'm wondering if setting number three will circulate the water better as it does seem to struggle which is where I think the air is getting in.

I will say the heating works fine from initial startup when it's just been bled, it's as soon as it's got to temperature and just fires up to keep that temperature that we start to get the problem with air.

Is there anything else I can try/check?

If you need anymore information I will gladly supply it if I can.

Would a picture of the layout help?

 

[migoplumber]

sound like a can of worms, without more information, first guess would be flow and return on boiler from your tank feed could be reversed, check out some instalation diagrams from internet and try to trace the feed and expansion (f+e) from tank to your boiler connections.
even if you dont trust the installers, they are legally obliged to leave you without problems, contact trading standards if there is a real problem
shaun

 

[pnhsolutions]

Where do we start?

Post some drawings and we can try and work this out!

Sounds like the pump may be pulling air in?
Or you have a dodgy AAV?
As above with the pipework crossed?

You should really get in contact with the installer as he knows the system better than anyone (apparently)

 

[Bob1985]

Thank you for both of your replies.

I have included a diagram of the pipework, please excuse the quality.

A little more information - we have 6 radiators, the only one that has never had air in it is the one that controls the room stat, this has lock shields fitted, all the others have thermostatic valves fitted.


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[traineedrip]

very new to this so jump in if i`m wrong experienced peeps but

the expansion pipe shouldnt join the feed pipe. they should connect to the main flow pipe seperatly

the pump seems to be pumping downwards so should have an air seperator prior to it.

 

[Bob1985]

very new to this so jump in if i`m wrong experienced peeps but

the expansion pipe shouldnt join the feed pipe. they should connect to the main flow pipe seperatly

the pump seems to be pumping downwards so should have an air seperator prior to it.

Sorry, that will be the way I have drawn it, it doesn't join it directly, it tees off and goes off separately.

I was never good a tech drawing.

 

[HTB]

Are you certain the system is refilling after you bleed it? Try isolating the supply to the F&E (Header) tank and bleed the system. The level in the tank should drop as you bleed. If it doesn't then the feed is blocked and this could be part of the problem.

 

[Bob1985]

Are you certain the system is refilling after you bleed it? Try isolating the supply to the F&E (Header) tank and bleed the system. The level in the tank should drop as you bleed. If it doesn't then the feed is blocked and this could be part of the problem.

Pretty sure it is refilling, I say this as we have had two replacement radiators fitted and the system has been drained and refilled.

But I will double check - cheers.

 

[leakylea]

you say that the tank ran dry in 5 days, it would not really matter what way it was piped or not piped. the amount of water in the system would remain the same it just would not work unless it was overflowing etc.
have you checked for leaks under floors,turn off heating turn off supply to tankif water level falls you have leak! good luck
water only leaves your system fro overflow or leak

 

[Bob1985]

you say that the tank ran dry in 5 days, it would not really matter what way it was piped or not piped. the amount of water in the system would remain the same it just would not work unless it was overflowing etc.

The tank run dry and boiler stopped working 5 days after they installed the boiler as they forgot to turn the cold feed to the header tank back on, I switched the boiler off, turned the feed back on, bleed the system then restarted the bolier, all was fine but air was still entering the system.

have you checked for leaks under floors,turn off heating turn off supply to tankif water level falls you have leak! good luck
water only leaves your system fro overflow or leak

They only changed the boiler, everything in the loft was is ok.

Prior to having the boiler changed the system was fine, no leaks, no problem with air.

Had two radiators replaced recently, checked the install, all ok.

So as far as I can see there are no leaks.

I will do as you have suggested and double check.

Thanks for your advice.

When I'm in the loft I can hear the air in the system in the area of the header tank/boiler/pump.

 

[danielp]

well if your cold feed was that high i can see the problem

looks like it is piped corrctly with a bypass fitted can only be the pump drawing in air??

 

[Bob1985]

well if your cold feed was that high i can see the problem

looks like it is piped corrctly with a bypass fitted can only be the pump drawing in air??

Would you recommend an air separator to be fitted just before the pump or would a couple of automatic bleed valves do the trick?

I have been put in touch with a reliable plumber who could do the work, I'd rather pay them than recall the original company - I just need to know which way to go so I can inform them what work is required.

Thanks for all the help.

 

[Bob1985]

The pump may need to be wired directly from the boiler. If the wiring has not been changed then when the boiler stops the pump does too. This will cause the boiler to boil, lose water, alow air into the system and make the noises you mentioned. Check, when the boiler is firing, turn off the demand from the clock, does the pump stop or run on for a few minutes

Hi.

The pump is wired to the boiler and runs for a while when the boiler stops.

I have an engineer booked for tomorrow who is only going to charge for the physical work done, they are not charging me a call out charge or charging me for any diagnostic work - they are a friend of a friend.

Hopefully it will be sorted out, I will post the outcome for those interested.

Thanks to everyone for the help/advice/ideas.

 

[migoplumber]

on your drawing, you need to mark the pump direction. ( little arrow on pump body )
is your f+e tank water cold or hot??
shaun

 

[Bob1985]

on your drawing, you need to mark the pump direction. ( little arrow on pump body )
is your f+e tank water cold or hot??
shaun

Engineer has called and said pump has been installed correctly.

Their diagnosis revealed the install (pipework) has been done incorrectly.

They have installed it as an open vent system when it should be low head install. The distance between the open vent and the water level is far less than the recommended 18".

The header tank is too close to the boiler in height for the type of pipework they have done, an air separator needs to be installed between the boiler and pump where the air vent must be below the cold water level.

They really should have looked at the fitting instructions more carefully as the guy picked up on this straight away after he had carried out general checks on the system first, leaks etc.

Just waiting for him to give us a date for the work to be done.

Once again, thank you for all your help and support.

I have included the installation manual to give you a better idea - Page 10 fig3 is how it's been installed - page 11 fig5 is how it should have been installed.

http://www.idealboilers.com/docs/pdf/icos_he_manual.pdf

 

[traineedrip]

glad you got it sorted. thanks for the info and link

 

[migoplumber]

well done mate.

good perseverance.

do you spell it like that??

shaun