Magnetic Filter for Inexpensive Combi?

[JonE]

Looking at a couple of surprisingly hefty quotes for new combi to replace system boiler (etc.).

Can it really be worth spending almost £200 to have magnetic filter installed with a Baxi 228 combi which retails under £720(inc)?

Boiler has only a 2-year guarantee so I don't expect it to last too long anyway. Mag filter is no great shakes for non-ferrous crepe and £200 would buy a fair bit of inhibitor.

Any MagFilt fans want to try converting me to their view?

Cheers!

[MrFoolish]

I've heard some people saying these filters can leak, and this has put me off getting one.

My current intention is to do a Fernox flush every couple of years or so. They are not too tricky to do yourself if you can handle a hosepipe, a funnel and a spanner.

[88V8]

The gas boiler in our previous house was 21 years old when we left, and going strong. I forget if it was a Potterton or a Glow-Worm.
At any rate, not a combi.
I kept an eye on the Fernox level, never needed to flush.

No filter. Why would one need a filter in a closed system?

V8

[Dicky99]

Looking at a couple of surprisingly hefty quotes for new combi to replace system boiler (etc.).

Can it really be worth spending almost £200 to have magnetic filter installed with a Baxi 228 combi which retails under £720(inc)?

Boiler has only a 2-year guarantee so I don't expect it to last too long anyway. Mag filter is no great shakes for non-ferrous crepe and £200 would buy a fair bit of inhibitor.

Any MagFilt fans want to try converting me to their view?

Cheers!

Are you getting that system power flushed before installing the new boiler?

That'll cost a few hundred quid but if it's not done no amount of inhibitor will protect your new boiler against the years of crud that's already sat in the bottom of your rads.

A Magnaclean Pro 1 can be bought for £85 which includes £15 worth of Fernox protector. It's false economy saving that £70 difference IMO especially considering that the Magnaclean is also a really convenient access point for future Fernox top ups. Isolate it at the top and bottom valves, unscrew the cap, suck the water out of the pot, pour in the Fernox, screw the cap back on and open the valves.

Irrespective of the length of guarantee if the system is power flushed and the boiler well installed and protected with inhibitor it should give at least 10 years service. My Potterton was fitted 15 years ago and shows no sign of its age.

[moorfield]

Looking at a couple of surprisingly hefty quotes for new combi to replace system boiler (etc.).

Can it really be worth spending almost £200 to have magnetic filter installed with a Baxi 228 combi which retails under £720(inc)?

Boiler has only a 2-year guarantee so I don't expect it to last too long anyway. Mag filter is no great shakes for non-ferrous crepe and £200 would buy a fair bit of inhibitor.

Any MagFilt fans want to try converting me to their view?

Cheers!

A new boiler should be under warranty and the manufacturer might require it anyway.

It will of course make your house a bit easier to sell if you intend to do in the next 10 years, if you can advertise a well maintained CH system. £200 well spent.

[Mike4]

Mag filters are generally a complete ball ache in my opinion. When servicing a boiler I avoid disturbing them in any way if possible. If the customer specifically wants it cleaned out then I make it clear the extra time involved (anything from 10 minutes to perhaps an hour or two if it goes badly) is chargeable in addition to the price I've given them for a boiler service in accordance with the manufacturer's service schedule.

I reckon when a customer insists, I'm usually the first person ever to take it to bits.

And don't even get me started on the quarter-turn isolator valves on them which can leak when disturbed, necessitating a drain down, a visit to the merchant and a return visit to fit a whole new filter as the merchants never stock just the isolators, all taking up probably half a day at £xxx per hour....

I'm probably over-egging it, but I've learned not to touch them!

In fact mag filters (along with expansion vessels and pressure relief valves), are the main reason I specialise in the excellent, well built, vintage, non-condensing boilers of the 80s, 90s and early 2000s which have none of this ol' tosh, to the exclusion of all modern boiler work.

When plumbers tell you 'parts are not available' for your old but oh-so-reliable vintage boiler, it ain't necessarily so


(Edit to add a bit.)

[Dicky99]

And don't even get me started on the quarter-turn isolator valves on them which can leak when disturbed, necessitating a drain down, a visit to the merchant and a return

When my quarter turn valve leaked once I discovered so many comments like this on DIY BBs when searching for advice. I didnt find any help so had to find the solution myself and it turned out to be very simple. I removed the unit and took a good old fashioned look at it. The valve isn't cast in one piece, it's two stems screwed into the main body, which is not obvious when looking at the outside of the valve. When you look inside the valve you see that the innards are hex shaped for a reason. If the valve is leaking from the main body that threaded stem has loosened slightly by disturbance and just needs tightening up. I spent a couple of days scouring the net without any useful responses other than "these valves leak when disturbed I use this one instead" so I'm of the opinion that nobody knows this and maybe the manufacturers don't feel the need to share that information.

[88V8]

...no amount of inhibitor will protect your new boiler against the years of crud that's already sat in the bottom of your rads.

As with the filter... why?
There was no crud in our rads, after a total of 31 years (the boiler was upsized after 10 years due to an extension). A properly maintained system does not accumulate crud.

One can generally know whether the system has crud/corrosion issues... if the rads need bleeding, it does, if not it doesn't.
And ours didn't.

V8

[Dicky99]

There was no crud in our rads, after a total of 31 years (the boiler was upsized after 10 years due to an extension). A properly maintained system does not accumulate crud.

One can generally know whether the system has crud/corrosion issues... if the rads need bleeding, it does, if not it doesn't.
And ours didn't.

V8

So by extension no-one else's system has corrosion products in it just like yours?

The need for bleeding is an indication of air in the system not corrosion products.
Rads cold at the top, air in the rads. Rads cold at the bottom build up of corrosion products.

[kempiejon]

The need for bleeding is an indication of air in the system not corrosion products.
Rads cold at the top, air in the rads. Rads cold at the bottom build up of corrosion products.

That's what I thought too. As a lad I worked as a plumber's mate in the school holidays. One morning we went to a house to change a rad which was cold at the bottom. There might have been more to the job but that's all I remember because I was mortified by my cock up. Down stairs living room white shag carpet; me and the plumber are manhandling a large cast iron radiator of the wall. We had cloths down but when I dropped my end and the two pints of thick black sludge poured out one end it ran over and seeped through our sheet. We heard then that the carpet was new, tidied up as best we could and the boss had to book a carpet cleaning company. I don't think I worked for them next holiday.

[88V8]

There was no crud in our rads, after a total of 31 years (the boiler was upsized after 10 years due to an extension). A properly maintained system does not accumulate crud.
One can generally know whether the system has crud/corrosion issues... if the rads need bleeding, it does, if not it doesn't.
And ours didn't.

So by extension no-one else's system has corrosion products in it just like yours?
The need for bleeding is an indication of air in the system not corrosion products.
Rads cold at the top, air in the rads. Rads cold at the bottom build up of corrosion products.

I can't speak of other people's systems, but if you were to ask the average punter how their system works and the presence of inhibitor or not, I think you would get a blank look.

Air does not get into a well-designed system. If it does, it leads to corrosion. When the rads need bleeding it is because of outgassing due to corrosion product... rotten eggs smell... and that happens due to the presence of air from 'pumping over', or absence of inhibitor perhaps because it was never there or has been diluted by leaks, or has been lost due to alterations/draining and never replaced.
Inhibitor is expensive and not all plumbers are assiduous in replacing something the customer does not even know should be there.

If a system is letting air in, flushing and changing the boiler will not prevent a recurrence of problems. One would need to ascertain why there was crud in the first place.

V8

[jaizan]

1 A friend fitted a magnetic filter to an older CH system, himself. This collected quite a lot of crud when first installed, but eventually the quantity reduced as it was filtered out.

2 I fitted the same filter to my system, myself. My system has had plenty of Sentinel corrosion inhibitor in from new, so it hasn't collected much crud.

The filters cost about £50 to £90, plus the cost of another bottle of sentinel, as I usually top up if draining part of the system. They are usually easy to install, although it does depend on your pipe routing.

Mine doesn't have any taps to leak. I don't see the point of taps, as when I drain it, I can turn the CH off to stop circulation and the water pressure in the system is useful to force any accumulated crud out.

[JonE]

When questioned, the GasSafe-registered box-shifter had advised that a MagFilter wasn't included in his original (devoid of detail) quote but, if I wanted one, he could add a filter for 160+VAT.

Following further questioning (which reportedly caused him to make enquiries of the boiler manufacturer) he has now said that, although not required to keep warranty valid, I'd have to specify a filter to achieve Building Regs compliance!

I've checked and this reg appears to have come into effect on 15/06/2022 so how come he was quoting for a replacement boiler install without a filter over a year later - during which period he presumably actually installed per quotes and without filters yet issued certification?

The search for a local plumber who hasn't recently de-registered from GasSafe (as several have) and can do anything this side of New Year continues...

Cheers!