air getting into system somehow - please help

[bradchop]

I have a customer who has a 3 bed semi with 8 radiators in (4 up 4 down). the boiler is a floor standing potterton boiler. the original problem is that 2 rads upstairs werent getting hot at the top.i filled up the system like you do, half hour later it dropped by atleast half way again. i heard a bubbling sound from near the boiler and assumed that a small leak was evident on the downstairs bit, so i renewed the whole downstairs pipework. as i was doing this for 2 days i isolated the top half and filled it up - it worked fine - no apparent leaks. when all was said and done i filled up the whole system and no leaks evident. a week later i get the call saying the same problem is evident. can anyone help me please? if there are no leaks then how does a system produce air?

pump is set to level 1

system is open vented

only 1 rad keeps needing bleeding, the rest hold there own

 

[PlumbBobBob]

possibly not air but hydrogen produced by system water reacting with radiator

 

[bradchop]

thanks for the reply...... that might be the case. so a good powerflush is in order then?

 

[PlumbBobBob]

yes to thoroughly clean the system

 

[shorticus]

There's a simple test to check whether it's hydrogen and ergo system degradation/electrolytic reaction but I'm not overkeen on telling people what it is on account that some may say that it doesn't comply with health and safety regs lol.

Have you put any inhibitor in? I'm assuming that given you've renewed a lot of the piipe-work that you also gave the system a raw water flush!?

 

[bradchop]

did a thorough powerflush today...hopefully that should sort it out. fingers crossed. i double checked the f and e tank and the vent is well over 450mm above the height of the height of the water. the water level is fine. i even gave it a good clean out when it was drained. and yes i have put inhibitor in.
if i get the call that im dreading then i will let you guys know. thanks for your help

 

[nurse_77]

Re: Heatline boiler problems ++++

Hi everyone, Not a plumber and need help. Got new circuit board on my Heatline boiler last week. All fine but one week later...pilot light not igniting, warning light flashing. Have checked radiators..no air locks..Any suggestions ???

 

[Reg Man]

Sounds like an open vented system? Has the pump been replaced recently? Are the open vent cold feed and pump correctly situated? Check the header cistern to see if its getting hot. This could indicate problems with the pipework configuration.

 

[nurse_77]

Thanks for that. Led light flashing to indicate low air pressure. Pump not changed recently. One of radiators has a small water leak , could that be the cause.Will check heater cistern : As for working out the correct location of vent cold feed and pump : Think i'll get service man in...We are very familiar with each other at this stage unfortunately.

 

[Phil]

Thanks for that. Led light flashing to indicate low air pressure. Pump not changed recently. One of radiators has a small water leak , could that be the cause.Will check heater cistern : As for working out the correct location of vent cold feed and pump : Think i'll get service man in...We are very familiar with each other at this stage unfortunately.

No need to thank him, he wasn't talking to you nurse_77!

Its best to start a new thread on your problem or it gets confusing lol. :43:

 

[fuzzy]

is it a vip system?

 

[bradchop]

thanks for your reply Reg man. the pump hasnt been changed for over ten years, it was on setting 2 but ive set it to level 1. the header tank is luke warm. by the way i got the dreaded phone call to say that the same problem is here. One radiator upstairs is full of air.....doh!! i havent checked the pipework as the original plumber has connected it upstairs beneath the floor. i did notice that the pump is positioned infront of the boiler at a weird angle? ive even thought about buying one of those auto vent rad valves lol

 

[bradchop]

what do you mean by vip pal? or are you talking to the other guy who turned up on this forum? thanks

 

[fuzzy]

is the first tee the vent, second the inlet and then the pump? if not you could be dragging in air or pumping over, both could lead to these problems.