Where is the mesh filter on this inlet control group?

[harrypotter]

I'd like to clean the mesh filter. Cylinder manual says "Unscrew the head in the inlet control set and clean the mesh filter within". Which bit is that? (I know to depressurised everything before, don't worry) Thanks

 

[harrypotter]

SOLVED, in case anyone finds this thread in the future.

# Range TS201 or Caleffi inlet control group multibloc 3/6 bar

The 'head" in question is that grey part. Manual says to unscrew that part then use some grips to pull out the internal cartridge using the exposed hex head. The mesh filter will be then accessible. I pulled with all my strength but couldn't get it out. In the end I bought the entire multibloc and replaced it.

Before throwing out the old one, I again tried to remove the internals by pulling on it. Basically impossible. I had go through from the opposite end to hammer the thing out.

 

[Johntheo5]

They must have known that its not easy to clean this filter.

 

[harrypotter]

They must have known that its not easy to clean this filter.

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Yeah no idea how they thought I could pull out the cartridge gripping on to a 6mm or so hex. It took a few very hard whacks with a hammer to push out. Although I do live in a hard water area and that things been there for 13 years or so.

 

[Johntheo5]

Of course, should have asked, what condition was the filter in after 13 years?

 

[harrypotter]

Of course, should have asked, what condition was the filter in after 13 years?

Oh not bad really. Nothing gunky, just what seems to be a few large pieces of grit or stone. The mesh was about 95% clear.

In the end I had to change the multibloc anyway because the pressure reducing valve was letting by. I looked at the rubber seal and half of it had eroded away!

I had to also replace the leaky cylinder PRV and expansion relief valve on the multi block (before realising I needed a new multibloc which came with an expansion relief valve). So I guess these things only have a 13 year or so lifespan with the water here in the SW. Not sure if that's good or bad.

 

[James1991]

Are you sure the pressure reducing valve was letting by? Normally when these things go wrong, the symptoms are low pressure. Out of curiosity, what pressure was on the expansion vessel when you de-pressurised the cylinder?

 

[Johntheo5]

Normally, EVs are sized to 10% of the cylinder volume and precharged to 3.0bar, the pressure reducing valve is set to the same, if the full contents are heated from 15C to 60C the final pressure will be 3.8bar, if the PRV is letting past and the pressure rose to even 4.5bar then the final pressure on reheating will be greater than 6.0bar and will lift the expansion relief valve.

 

[James1991]

Sorry John, l know what pressure it should be at. I was curious as to whether the vessel had any charge in it? After reading Harrys last post I think he meant relief valve and not reducing valve. Burst and flat vessels are by far the most common cause of relief valves being activated and component failure. Harry, it would be worth checking the EV if you haven’t already.

 

[harrypotter]

Normally, EVs are sized to 10% of the cylinder volume and precharged to 3.0bar, the pressure reducing valve is set to the same, if the full contents are heated from 15C to 60C the final pressure will be 3.8bar, if the PRV is letting past and the pressure rose to even 4.5bar then the final pressure on reheating will be greater than 6.0bar and will lift the expansion relief valve.

Sorry John, l know what pressure it should be at. I was curious as to whether the vessel had any charge in it? After reading Harrys last post I think he meant relief valve and not reducing valve. Burst and flat vessels are by far the most common cause of relief valves being activated and component failure. Harry, it would be worth checking the EV if you haven’t already.

I had written a reply but it must've forgotten to post it!

So all of this has been a learning experience for me. I do DIY plumbing but never touched pipework around the boiler/cylinder area.

In total 3 things were faulty.

Firstly the PRV valve on the cylinder was constantly letting by. I had a big company come out and at that time I new nothing about unvented pipework. They charged the vessel up to 3 bar as it only had 1 bar in it. It hadn't been serviced in years (that will change). And they said the cylinder PRV was faulty and wanted £250 to fit a new one not including the £80 call out. Having seen the PRV online for £20 I thought that price was a bit steep so I found a local bloke who did it for £60. They saw I do a lot of DIY so explained how it works a bit.

After the PRV was replaced there was still water going through the tundish so I spoke to the plumber and they said it could be the Expansion Relief Valve on the multibloc. The plumber said that I could do it so I did some research and changed that.

After those two were replaced the ERV was still letting by but only when the water was being heated up. I noticed the manual opening knob was very very easy to twist to let out more water so I suspected it was getting close to it's rated 6 bar. Checked the pressure of the EV and it was indeed just below 6. I also checked that the diaphragm wasn't blow or the valve wasn't leaking. Relieving all cylinder pressure the EV returned to 3 bar. But when I closed tap and put mains back on the EV would creep up to 4.5 bar without the boiler coming on.

So spoke to the plumber and someone else on this forum and they said it could be the pressure relief valve that was letting by. Made sense, so changed the multibloc. While doing so I made sure the EV was still at a pre-charge of 3 bar. Looking at the old valve and seat on the pressure reducing valve half of it was eroded away so that was 100% an issue.

The cylinder is 300l, and EV is 22l. I posted a thread on this forum about this having read about the 10% rule of thumb but someone worked it out and reassured me the pressure in the EV wouldn't be too high at 65°C.

All in all a good learning experience for a DIY'er.

 

[Johntheo5]

That was me Harry, a 22L EV with pre&filling pressures of 3.0bar will result in a final pressure of 4.33bar when 300L is fully heated from 15C to 65C, it will only require the pressure reducing valve to pass ~ 4.0L to increase the filling pressure to 3.9bar to result in the PRV lifting at 6.0bar. A non drop tight pressure reducing valve could pass that vol of water especially if the mains pressure is high, although I rarely see it stated that its a requirement to install a drop tight valve.

Should also maybe add, that the precharge pressure could be as low as 1.4bar, or fall to 1.4bar, before the PRV will lift at 6.0bar.

 

[harrypotter]

That was me Harry, a 22L EV with pre&filling pressures of 3.0bar will result in a final pressure of 4.33bar when 300L is fully heated from 15C to 65C, it will only require the pressure reducing valve to pass ~ 4.0L to increase the filling pressure to 3.9bar to result in the PRV lifting at 6.0bar. A non drop tight pressure reducing valve could pass that vol of water especially if the mains pressure is high, although I rarely see it stated that its a requirement to install a drop tight valve.

Should also maybe add, that the precharge pressure could be as low as 1.4bar, or fall to 1.4bar, before the PRV will lift at 6.0bar.

Oh I see now, thanks for the help

 

[Johntheo5]

You can do your own calculations here, I had to Zip the file to post it.

 

[harrypotter]

You can do your own calculations here, I had to Zip the file to post it.

Thanks, I was just about to ask for the formulas!