Frequent bleeding of Magnaclean

[Alfie25]

I've posted about this last year but thought I'd start a new thread now I have a bit more information.

I have a fully pumped open vent system, combined feed and vent. As you can see from the pic below, the magnaclean is installed (incorrectly I believe, and by BG, but that's another story) on the flow to the HW cylinder.

Fot the past few months I've not had the heating on, just the HW, and there has been no air at all building up in the magnaclean so I can assume my problem is not due to the HW circuit/pipes. I have had the CH on recently so the 3 port valve is of course directing water to both the CH and HW circuits and my problem of air building up in the magnaclean is re-occuring every couple of weeks or less.

I dosed the system with Fernox F1 in October last year. Given that air seems to be building up only when the CH (rather than HW) is involved, does this help diagnose the problem? I find it difficult to tell if the air is air or gas, as I don't want to stick a match to a plastic magnaclean when I'm bleeding the air off! It's not loads of air, but enough to make the magnaclean gurgle, so I know when it needs bleeding.

Untitled

• Alfie25
• 3 Sep 2013
• 1

 

[45yearsagasman]

I don't usually slag BG (I worked for them) but that Magnaclean installation is about as much use as a chocolate teapot. The air problem needs to be investigated. You must determine whether it's air and not hydrogen. Wait until; there's a fair amount of air in the Magna and then try venting and see if the gas ignites. The bleed screw is metal and this can be done safely.

 

[Alfie25]

Yes I'd posted that pic before and got a similar response about the location being hopeless, however all the system water is flowing through it when the CH and HW are on together, and from when I cleaned it last time (after a 6 month spell since the previous clean) it had caught a noticeable amount of magnetite - not loads, but certainly some.

It's the noise that bothers me once it gets air in it. I always feel like I should bleed the air out. If I leave it, is there any chance the air bubble would force its way out of the pipe and along the pipework or would that never happen?

I have tried catching the air/gas in an upturned glass and there was once a very small woosh when I put a match to it, but the second time I tried, it didn't seem to affect the flame.

 

[45yearsagasman]

I don't think the air will escape by itself, once trapped in there. During the Winter, when the HW is satisfied, the Magnaclean is doing absolutely nothing to remove debris from the system rads. Why could it not have been fitted on the supply to the 3 port valve, ie fitted between the pump and the 3 port. It would always be in play there.

 

[Alfie25]

I understand what you're saying - the magna will be doing sweet FA when the circuit is on CH only. I suppose the installer just thought there's not a lot of room between the pump and the 3 port valve so would have been difficult/impossible to fit in. Not that that's an excuse for placing it where it is!

It's not even wired correctly. You can't have the CH on on its own. If you turn on the CH it goes to CH and HW, until the thermostat on the cylinder is satisfied, only then it goes to CH only. However, this is an issue I can live with. The air/gas on the other hand, is a bit of a pain.

 

[Tom1981]

Before worrying about the air, get BG back to move the filter.
The filters the highest point on the system to is naturally going to collect air there.

 

[Tom1981]

I understand what you're saying - the magna will be doing sweet FA when the circuit is on CH only. I suppose the installer just thought there's not a lot of room between the pump and the 3 port valve so would have been difficult/impossible to fit in. Not that that's an excuse for placing it where it is!

It's not even wired correctly. You can't have the CH on on its own. If you turn on the CH it goes to CH and HW, until the thermostat on the cylinder is satisfied, only then it goes to CH only. However, this is an issue I can live with. The air/gas on the other hand, is a bit of a pain.

You system isn't wired incorrectly, it's Hot Water Priority. It's an outdated system. Can be upgraded easily

 

[gigz]

What kind of boiler do you have ? Best place for a magnaclean is as close to the boiler on the return. Could you not relocate it there and fit auto/manual airvent in the magnacleans place ?

 

[Alfie25]

I'm not with BG but the previous owner was, and that's who put the magnaclean where it is. I can undertstand air is going to collect at the highest point of the system but even if the magna was replaced with an auto/manual airvent, it still doesn't make it right that air is collecting there quite so frequently does it? It wouldn't be normal practice to manually bleed an airvent in the same place every fortnight or so would it?

The boiler is a Worcester Greenstar system boiler on the kitchen wall with the pipes exiting upwards into ceiling. There's nowhere I can see that a magnaclean could be fitted.

 

[gigz]

Is it possible to cut into the return and drop to the side ? As you say, you still need to sort air problem, more pics of the pump/fill and vent might help. All the carp from your system will be going through the boiler.

 

[Alfie25]

Is it possible to cut into the return and drop to the side ? As you say, you still need to sort air problem, more pics of the pump/fill and vent might help. All the carp from your system will be going through the boiler.

I suppose you could, but then you'd have a magnaclean suspended beside the boiler. You said that putting a automatic air vent release where the magna currently is would be an idea, but surely I'd be no better off than doing what i'm doing now - i.e. bleeding every 2 weeks?

The boiler is 5 years old now and so has had 5 years of the magna being set up this way so surely any damage from dirty system water is already done. Why the last owner just didn't fit a combi and rip out all the old is beyond me. Seems madness putting a new boiler on a fully pumped old fashioned system from the 80's.

 

[Boilerman2]

The Magnaclean is in a stupid position - but many have already stated this - the air build up may be as a result of the system sucking in air, (unlikely if combined feed and vent), or more likely a lack of corrosion inhibitor in the system leading to creation of hydrogen gas (same as air) - get the MC correctly located on the Return B4 the Boiler and add inhibitor when refilling system