Boiler Question

[shiftin_gear98]

Morning Org.
Last night I removed a radiator to decorate behind - no real drama, was the first time I'd ever done it though.
Anyhow did what I needed to do including relocate a power socket that was behind the rad!!


Put it back on, pressurised the system turned the boiler on as house freezing and went round bleeding all the rads. Whilst topping up the pressure in the system as I went. Wondering if I should have left it off whilst I did this.
Sorry should say Vaillant EcoTec plus 831 boiler 13 months old.


Wife came home with the kids just as I was finishing so I rushed the last couple of rads. Went to check the boiler and there was a warning of low pressure - again no biggie as it has a safety cut out. So I topped it back up to around 2 bar. And it came back to life. System 0.8 - 3 bar.
Did a final loop of all the rads to check no leaks, went back to close up the flap. When it all went pear shape. Water was dripping from the left hand side panel bottom seam. Poo. Really had enough now.


Run to get a couple of bowls. After a look in the book, I get the front off. and water is coming out of the Automatic Air Vent on the pump.


I have closed this off and stopped the water, trying to get hold of the gent who fitted it for us. If I crack the cap even a 1/4 turn open the water starts again.


My questions to you wonderful plumbers out there.


WHY is it doing this?
If it's an air release how is water coming out of it now?
And is it ok for my wife to have the heating on today with this cap closed? Oh and whilst I asking, would it do this every time I want to remove a rad?


Thanks Martin.

[Stingo]

Not a boiler maintainer or plumber - disclaimer. But I have an engineering background for what it's worth.

If I had blocked up an air vent on a boiler I'd be waiting for the repair person to come and sort out the defect before turning it on. There has to be a reason it has a vent irrespective of what's coming out of it. If you block a vent up, pressure has to build up...and if it can't get out of the vent, where is it going to go?

[DuncanC]

1. The automatic air vent is similar to a float bowl in a carb. When water is present the float lifts and shuts the valve. When air is present the float drops and lets the air out. Just like on a carb if you get crud on the seat the valve will leak.
2. Turning off the automatic air vent is no different to it being shut because there is no air present so it will be safe. The only downside is that any air that goes past the automatic vent won't be vented so will satay in the system. Unless you have a massive amount of air in the system it won't make any difference. The worst that could happen is the pump will lose its prime if it fills with air. if this happens then the low flow switch will shutdown the boiler.


I have to ask why did you drain down the system to take a radiator off? What is wrong with the valves either side of the rad?


For future reference I always bleed the system with the boiler and pump off. Once I have been round once I start the pump up for a bit to push any air to high points (radiators). I then stop the pump and bleed the system again. After that I just turn it all back on. If it starts gurgling I will bleed the radiator that is noisy again.

[DuncanC]

Stingo,
If it is a normal boiler it is vented to the header tank in the loft. If it is a combi it will have a pressure relief valve.
The reason to vent the air is that 1. it will stall the pump. 2. air in the system really reduces the heat transfer between the water and the radiators. 3. It makes really annoying noises when the boiler fires up in the morning.

[shiftin_gear98]

DuncanC Thanks,


Bled the system as I'm an idiot. Might try your suggestion next time. It did cross my mind.
Whole system is 13 months old - Boiler, rads, pipework. Was a one pipe system when we moved in.


How do I unblock or dislodge the trapped float?


Drain it all again, and remove / wipe. Or would a couple of taps free it up? Or would it sort itself out (unlikely)?

[Stingo]

Thank you DuncanC - noted. I like your easy to understand description...even I can understand it! Everyday a school day.

[Red ones]

Have you got boiler insurance?


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[Bibio]

if its a combi boiler just shut the rad off at the valves like you did to take the radiator off. combi systems are flow/return to each radiator so you can shut off any rad you like.

the reason you are getting leaks is that you have tightened the nut up too much and crushed the olive and possibly punctured the copper pipe in the process. this is a common mistake by people. the olive only needs to be tightened so it 'seals' not done up like a wheel nut by a monkey. its a compression fitting not a nut and bolt.

turn the offending rad valves off until you can get someone in who knows what they are doing.

or ignore me as i'm wrong...

[shiftin_gear98]

Spoke to the guy who fitted it. He said it must be due to that pressure drop, the float must have stuck as it lowered allowing water to pass by it. He has said it's fine to keep it like this. Quite typical for these valves. He did say it's still under warranty so I could get Vaillant out to fix it. So I might look into that after Xmas. Having looked online you can pick up a new valve for about £15.00. Might get one and drain it again. Likewise I might also just do what he said and leave it till next Nov when he'll be back to service it. Tapping it didn't help.
As there is no air coming out I think I'll forget about it for awhile. Missus op next week. Another day another thing learnt.

[DuncanC]

Personally if the system is bled I'd leave it until the spring as most likely you will have to replace the automatic vent.
It might be worth checking out boiler cover as this usually includes your annual safety check which you will need anyway.
Obviously don't mention you've messed with the system as some engineers get sniffy about anything inside a boiler even if you go nowhere near the gas.
Just turn the vent back on before the engineer turns up and mention you keep losing pressure from the system.
Lesson, never mess with your heating during the winter always do it spring so you have months to fix it.

[DuncanC]

Sorry cross post, get the vaillant man out you've paid for a good boiler so make the most of the warrenty.

[shiftin_gear98]

Thanks DuncanC, lesson learnt - use the sodding valves on the radiator!
Could it be simply a case it taking it out and wiping and putting it back in? Looks like you just pull that metal clip out, obviously once drained and off. As mentioned whole system is fairly new, just had its year service last month. Also got one of those magnet filter things on it to catch the crap.

[DuncanC]

If it's under warranty get it fixed. If you mess about with it and something else goes wrong you end up in the world of "well if you hadn't done that then it wouldn't have failed."
That and gas safe are getting very sniffy about people messing about inside boilers.
Also your house insurance might take a dim view of it as well.
Basically if you can get it fixed for free do so as it isn't worth the potential hassle.

[Red ones]

Always take out boiler and heating system insurance cover. You can usually find it at £10pcm. It includes an annual inspection which is usually £80, so you're paying £40 a year to cover almost everything except when the boiler is truly dead and is scrap.

[SV650rules]

Can't see a problem with leaving the pump airvent closed as the system should have an overpressure (set to 3 bar) vent anyway straight next to the boiler (between the boiler and the manual shut-off vaves) that vents to an outside pipe (these sometimes stick open as well - oh joy). Yours is a pressurised combi boiler so the boiler has two heat exchangers, one for the hot water and one for the radiators and piping is completely separate (hot water side has a pressure switch that detects pressure drop when a tap or shower is turned on and fires up the boiler). Any trapped air will normally find its way to upstairs rads so check if any of them not heating up.

I never take rads off to paint behind them, it's just tempting fate. When you mess with household stuff that ain't broken things can snowball quickly - and modern boilers are tricky - they have so many automatic and self-check stuff in them.

If you have a thermostatic valve on the radiator you need to take the thermostat head off (normally held on by a knurled ring) and screw on a maintenance cap that holds the valve properly fully closed (these are supplied with each valve but if someone else installed the valves they do not always pass them on to you) the valve on the other side of rad will be a lockshield valve (it has a plastic cap over it, this is the one the engineers use to balance the system flow (make sure one radiator is not stealing flow from the others), there is no handle on this one you will need a spanner to turn it, make sure you count the number of turns to close it and then when you have finished open it up the same number of turns)..

If you just have manual valves one of them will have a plastic handle on it - this is to turn off the flow through the rad, the other one will be a lockshield valve as above.

[maviczap]

Always take out boiler and heating system insurance cover. You can usually find it at £10pcm. It includes an annual inspection which is usually £80, so you're paying £40 a year to cover almost everything except when the boiler is truly dead and is scrap.

Excellent point, mines being serviced today for £75, but I know that its going to need some extra work which I'll have to fork out for sooner or later

[Blapper]

The other important reason for not having air in the system is that you need to create an environment where corrosion does not take place. The monkeys that built my house didn't install a vent at all and had put a belly in the cold feed pipe (open system) so air could not even escape that way. Result is corrosion products blocking the manifold pipe so the system now needs power-flushing. £700 kerr-ching, thank you very much.