Y Strainer - technical

[Brambles]

If you were looking at a commercial system, you would take a fluid sample - and determine the filter size to remove no more than 75% of the suspended solids on three passes.

The problem with a domestic heating system is that the majority of the solids are static - in that the systems are not ( no disrespect to anyone in the domestic heating sector) designed to maintain a constant velocity. As soon as the velocity falls, the solids drop. Indeed, it would not be cost effective to design and implement a domestic heating system to be hydraulically efficient. You just need it to be optimised in a cost effective manner

As a consequence, once the system is clean and properly dosed, filters and traps et al are quite effective. However, they are most unlikely to effectively clean an existing dirty system.

Apologies for being pedantic, but in general terms for small bore hydraulic systems you filter / control the input, not the circulating fluids.

Sorry

 

[Stigster]

(Went into B.S.S - quote for a 1" BOSS Y-Strainer = £99. Overkill for my setup.)

So, as this thread is an a exploratory/discussion thread, I'm going to ask the following:

'What is the correct way/procedure to follow, to choose the appropriate strainer mesh perforation, for any install?'

Shaun suggested that 500 microns would be correct for my situation, with 50 microns only suitable for drinking water.

How can we best choose the correct mesh, for any given usage?

I'd go back to my question "What is the smallest waterway in your system?" and we can probably take it from there.
[automerge]1571732239[/automerge]

Radiator Valves and Thermostats | Resideo

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Any good? They say low flow resistance and give all the figures for the different sizes. I am not educated in this area of flow through valves/meshes though I have to admit. They do a 350 micron mesh and a 180 micron mesh. The 350 might be ok for your purposes?

 

[Ric2013]

Caveat that I'm not a boiler installer, but (and this is unusual coming from me), I do feel you are overthinking the situation.

To be honest, I've never heard of using a line strainer on a domestic heating system, but so long as you check the temperature ratings (I see the BES one will take 110°C) and the pressure drop, which it seems you are doing, I cannot see what harm it could do; as you say, a few old boilers did incorporate a mesh strainer on the return. Usually I use Y strainers on shower pump inlets.

I totally get your point regarding swarf circulating following any work carried out to a heating system. I would also agree that magnetic filters do not tend to catch 100% of the magnetic dirt (hence the Magnacleanse unit has two identical magnets one after the other and some dirt reaches the second magnet even when the quantity is very small). I would comment that the larger bits of copper swarf have a larger surface area and are, therefore, likely to be more mobile. At this point, ANY mesh should be enough to catch it.

What I would say, more critically, is that if you are soldering on a system or fitting a new radiator, then you really should be carrying out a chemical flush using F3/X300 etc to remove oil and flux. If you are flushing using a powerflush pump (and you can hire one for less than £50), you would hope that would kick out any swarf, although I can see that unless you are very careful where you place that pump and how you use it, you might well be forcing the swarf into the boiler.

Dissolved metals resultant from using flux will stop an inhibitor working correctly and if your boiler has an aluminium heat exchanger, then corrosion could be a more serious concern than swarf.

What I would say to answer your question is that the finer the filter, the faster it will clog. In aircon, the air filters are fabric and the dust can actually be forced through the mesh. The solution is to fit a succession of filters from coarse to fine such that the fine filter is never given the burden of the coarse dust. If you were to do that, I can see an argument for stepping down to a very fine final filter, and it would be interesting to see the distribution of various particle sizes.

BES also does a 200 micron filter, but I wonder if the cost/benefit ratio is starting to rise unacceptably?: In-line 'Y' Type Filter - 1" BSP TF 9824 | BES.co.uk