I want to improve my central heating system. The boiler is a non condensing Grant about five years old. The radiators are a mix of ones about 15 years old and a few much older. It has been suggested to me that adding a BoilerMag and having the system power flushed would be a wise move.
Constructive comments please.
Is it a vented or a sealed system? Is corrosion a problem at the moment? Is is regularly dosed with inhibitor?
Sealed systems tend to be somewhat less prone to magnetite collection, but they can still get it.
Non condensing boiler are also less likely to be damaged by debris in the water (the HEs being less efficent, have fewer very small easily clogged pathways).
Having said that, if the system is old of or unknown vintage, and you are not sure it has always been well protected, or, if corrosion seems to be a problem, then these filters will do a worthwhile job.
Not sure I like the look of the BoilerMag one particularly though. Its probably better than the Maganatec, but I think the Fernox TF1 is a better design since it also has a cyclonic collection action for non magnetic particulates, and the thing can be cleaned without dismantling (the magnet withdraws from its sleeve, dumping the collected stuff ready to be flushed from the bottom valve).
More on this and DIY flushing here:
I'd go with John on the TF1 rather than the BoilerMag - the mesh filter on the latter looks like a problem waiting to happen. Where space is tight Fernox do a stubby TF1, and Sentinel are in the market now. Both are currently (March 2013) on offer from BES under £100 with a bottle of inhibitor (Fernox/Sentinel respectively, natch) thrown in.
A point to note with current generation condensing boilers is that most have a drum style of heat exchanger involves primary circuit heat- exchanger pipework in a spiral on a horizontal axis which is at risk of blocking with sediment. And some if not all such exchangers have multiple loops in parallel so once one gets blocked you've got no way of forcing the blockage out by flushing.
Thanks to you both. A fantastic help to someone like me who knows little of heating systems. My system has a small header tank in the loft (in a bungalow if that is relevant so I assume that is open rather than closed. Inhibitor not changed for five years.
Header tank would indeed suggest vented. These are slightly more liable to accumulate crud as the exposed water allows fresh oxygen into the system, and this is what allows much of the corrosion in the firs place.
Inhibitor does not need "changing" as such, but does need topping up from time to time (one of the things it includes is an oxygen scavenger which will mop up and spare oxygen in there - needless to say that gets "consumed" over time).
So with your system, a pragmatic way forward would be to flush it, and see what state the system is in. If it appears to be reasonably clean anyway, then you can refill and add inhibitor and be done with it. If it looks like there is plenty of black crud in there, then also fit a TF1 or similar. (or if you need to hack about with pipework to make flushing possible, you may as well fit the TF1 anyway)
I'm quite interested in this as I have a system (sealed) of "mixed age" and despite use of inhibitor one of the old rads in particular is clearly underperforming and has sludge build-up.
How much crud do these filters tend to collect and how effective are they? I'm just wondering if I'd had one of these filters fitted over the years, how much of the sludge that's now sitting at the bottom of that rad would have been caught by a filter - presumably it isn't 'mobile' as such and wouldn't ever have reached the filter?
I'm probably going to replace the rad this summer, and am just considering wondering whether it would be worth dropping the £100 to fit a TF1 while it's drained down?
They are not a "cure all" in the sense that you can fit them to a sludged up system, and have it restore perfect health (since as you highlight, during normal operation some sludge once its come out of circulation will stay out of circulation).
However if you flush out most of the crud, they should slow or prevent the return of it. The sludge will tend to deposit where the water flow is relatively slow, or there is a notable change in pipe flow resistance (e.g. high volume of flow into a tee or elbow somewhere), so at some point its fair to assume the sludge is in suspension in the water in the system doing a few trips round the loop prior to getting to its favourite dropping off place. Hence if the filters can catch it more aggressively than the slow rad, they should prevent most of it being left there.
On my system (age unknown, probably not well maintained prior to my ownership) I flushed it manually when I changed the boiler (and that photo in the wiki article gives you an impression of what came out!), and fitted a TF1. After a couple of months of operation, I emptied the TF1 to see what it had captured. Drained a couple of cups of moderately black (grey?) looking water out of it, and chucked them in a bowl so that I could drain the water off and see what particulates were left. There was probably a teaspoon's worth of mostly black magnetite particulates.
And there was me thinking BoilerMag (incorporating Hacksaw Weekly) was a specialist publication for the likes of Drivel ...
^^^ or "cannot", maybe? :)
Yes that certainly fits with my system - there is clearly poor flow at my particularly duff radiator, which is at the furthest away point from the boiler and has never been good despite all attempts at balancing - that and the sludge inside is probably a chicken-and-egg thing. Sounds like a TF1 would probably be worthwhile once I've got that radiator off in the summer.
(Supplementary q: on a system like mine - sealed, with gas system boiler and mains pressure HW tank - is it possible to have the CH side drained down during the summer for maintenance over a period of time, while still allowing the boiler to heat the HW as normal? Or would I need to use the electric immersion heater?)
Well I meant what I wrote, but reading it now, it is ambiguous ;-)
For the avoidance of doubt - if you do fit one, don't expect it to restore a well sludged system to normal operation on its own, without also flushing it.
You will need a functional primary circuit... that could be just the hot water cylinder if you want, with no other calls for heat other than that. Whether that is more or less hassle is debatable.
(note its not a good move to leave rads etc drained down for too long - wet steel things full of air don't stay steel forever!)
Thanks for that John. I plan to get a TF1 anyway and change the old radiators for modern ones. Having looked at various sites I am totally confused by the number of makes and models. Performance is more crucial than appearance or cost. Please can you suggest where I start to choose a make? TIA
If you are not fussed by the aesthetics, then one make is pretty much as good (or poor) as another really these days (IME). So choose what you need in terms of heat output and size (that will also dictate single, double, or triple panel), and look for the best price.
I replaced a few recently, and went for ones that follow the normal stelrad design, but these were by some other manufacturer - as stocked by our local plumbers merchant...
based on the model number I would guess made by these people:
They seem ok.
Thanks John. Much appreciated. All I need now is some warm weather so the system can be turned off for a day! I Have made a note in my diary for July.
. All I need now is some warm weather so
Good luck with that :)
Which year? ;-)
(I think I managed to get all my heating system hacking about done in Oct - with about a week to spare before needing it!)
Replacement of our boiler being necessary we become without heating from lunchtime tomorrow for several days. Joy! :)
Surely a boiler change should not take more than a day. Or is there something more to this?
Mine took best part of a couple of weeks...
Partly because a boiler change is rarely just a boiler change... (even if swapping like for like, doing a proper flush of the system will take a good part of a day if done right).
If converting from one zone to two, going to a sealed primary, adding weather compensation, changing hot water from vented to unvented as well, and slapping all the controls and wiring, plus swapping half a dozen rads about it soon adds up!
Exactly. Today apparently starts with the 'freak the cats out' exercise with a rubberised hammerdrill going for the rad's that are staying.
Noted. But that is not what I would call a boiler change. It is a complete heating system refurbishment that is another matter entirely.
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