Magnetic Filter Location

[flick3k]

Hi everyone,

I’m looking for some clarification on the best location for a central heating magnetic filter please.

I have a unvented sealed system with a Potterton heat only boiler mounted in a kitchen cupboard. I can access the flow and return pipes before they disappear into the wall cavity but they’re quite tight against the wall and there isn’t a great deal of pipework to play with. I was hoping in this case I could install the filter in the airing cupboard instead.
All of my central heating pipework to the radiators is the pvc tubing type (new build house) and the point where the tubing rejoins the copper return pipe is under the floor in the airing cupboard somewhere. I have access to the return pipe from the hot water cylinder - would installing the filter here have the same effect?
Or would I be best trying to squeeze a compact filter in above the boiler?

Thanks in advance!
Chris

 

[EAST61]

It's likely that your hot water cylinder is on a different zone, so placing the filter on the return from your cylinder will only capture magnetite from that zone.

You want the filter close to the boiler on the common return pipe after all your zones have returned.

 

[chrisw99]

Sorry to hijack the thread.. Had a new boiler installed last week. Ancient pipework and had a chemical flush performed, and there's now a Magnaclean just before the return to the boiler.

How often should it be opened and cleaned? And should I do an initial clean so soon after it has gone in, in case there was a lot of crap dislodged due to the new installation, or does that not matter. Suppose what I'm asking, is there a way to know when the filter is getting full and requires cleaning?

 

[JohnD]

For the first week, empty it daily. For the next month, empty it weekly. For the next year, empty it monthly. After that, once a year.

This is based on my own limited experience with a dirty old system. If you open it and there is a thick coating, keep doing it often. When you open it and there is just a grey smear on the magnet, you know it's time to reduce frequency of cleaning.

You can wipe off most of the sludge, after sliding the magnet out, and you can wash away more under the tap. It can be interesting to scrape it into a jamjar and marvel at what a lot there is. The amount reduces as the filter slowly traps whatever is circulating, and as new sludge washes away.

 

[EAST61]

I say leave it alone until your annual boiler service. Open it once in a week’s time if you’re really curious.

Playing with it as much as JohnD has suggested will only increase the likelihood of it leaking imo.

 

[endecotp]

Sorry to hijack the thread.

So why did you hijack it then? Why not start your own thread for your question?

 

[endecotp]

placing the filter on the return from your cylinder will only capture magnetite from that zone.

Well, it's the same water. Magnetite from the radiators will be carried through the boiler and next time may go through the cylinder, and hence the filter.

It would certainly be best to have the filter on a common pipe, but if there is no practical alternative then what you suggest is better than nothing.

 

[EAST61]

Well, it's the same water. Magnetite from the radiators will be carried through the boiler and next time may go through the cylinder, and hence the filter.

It would certainly be best to have the filter on a common pipe, but if there is no practical alternative then what you suggest is better than nothing.

Yes it’s the same water, but the magnetite that was present in the water may no longer be, as it’s clogging the heat exchanger instead.

Of course I agree with you. But arguing against what I said seems unnecessary.

 

[Doggit]

As long as the cleaner is on the return leg of the pipework, then it can go anywhere that's accessible. There's nothing to stop you putting it in the airing cupboard, but there are some cleaners that shouldn't be too close to the boiler, as the extra heat can cause issues. The magnet can handle a lot of debris, so maybe check it after a couple of weeks, and then leave it till the annual service (assuming you have one of course) but as long as you have an inhibitor in the system, then it shouldn't really need checking.

 

[John D v2.0]

As long as the cleaner is on the return leg of the pipework,

You'd think so but I bought a spirocombi (air and magnetic) and it didn't really say where to install.

I checked the instructions for their magnetic filter... On the return to whatever you want to protect. The air separator... Hottest part of the system.

In the end I decided it didn't matter and bunged it on the flow and nothing has exploded yet! So just shove it anywhere, as long as it's on a bit that gets plenty of flow.

 

[Doggit]

There's normally an air separator in the boiler, so this isn't necessary in a mag cleaner, but as the return is cooler than the flow, this is the most appropriate place to fit them. It won't explode, but the extra heat may shorten the life of the magnet a bit, as well as the rubber seals.