Replacing a Filling Loop.... How?

W

Webby54

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Hi, I have a Potterton Powermax HE boiler and the pressure is regularly dropping since putting the heat on again just recently.

I top up the pressure by opening up the filling loop, but I've noticed a leak in the loop itself.

See the picture I've added.

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The valve at the bottom leaks/drips into the cup if I don't set the valve at the top right exactly in the right position, which is hard to do due to it's position behind the two pipes.

Ideally, I'd like to just replace this filling loop to eliminate this and work on trying to find other possible leaks.

What do I need to do to replace this loop? Just shut off the mains water supply and run the bathroom taps, and then simply replace the loop? I'd want to replace the whole thing from end to end including the valves, right?

Thanks.
 
Yes turn off the incoming main, for the cold side. For the heating side, keep the braided hose attached and then open the black tap and drain into a suitable receptacle. You may need paste or ptfe tape on the olives. Then replace the whole valves etc, and re- pressurise the boiler.
 
CBW said:
Yes turn off the incoming main, for the cold side. For the heating side, keep the braided hose attached and then open the black tap and drain into a suitable receptacle. You may need paste or ptfe tape on the olives. Then replace the whole valves etc, and re- pressurise the boiler.
Click to expand...

Thanks. Shame I didn't think about doing this yesterday as I had the water off to replace a kitchen tap unit!!

Ok, so to clarify, turn off mains, run taps dry, remove cold water end, and THEN open valve at other end to drain out, yes? How much water is there likely to be?

Also, I'm not seeing a loop exactly like mine.... This one looks close, and this one....?
 
Yes, either of those two, it’s just an external filling loop, so not specific to anything. Yes, your clarification is correct, although probably don’t need to drain the taps, as for heating side, it depends if the boiler is higher than rads, if it’s not, there may be a fair amount, and may need to vent any radiators above it.
 
CBW said:
Yes, either of those two, it’s just an external filling loop, so not specific to anything. Yes, your clarification is correct, although probably don’t need to drain the taps, as for heating side, it depends if the boiler is higher than rads, if it’s not, there may be a fair amount, and may need to vent any radiators above it.
Click to expand...
The boiler is upstairs so.......
 
I can't view your pic ?? Anyway ,if you are regularly losing pressure then you have a problem that needs attention other than the filling loop. What does pressure rise to when heating has been on for a while.
 
CBW said:
So, it should be ok, and minimum water. Also Terry is correct, you may have an expansion issue (I thought I addressed this - but only thought it :eek::LOL:).
Click to expand...

I'll look into that too, but this is clearly leaking so probably worth changing.
 
Ok, so I changed the filling loop on this last weekend; bit tricky as the pipes are very close and it was difficult to get a spanner or grips onto the top nut.

However, my pressure loss is much less now, significantly so. I haven't needed to top it up all week!
 
Last edited:
Well keep an eye out, if it stays the same - bonus, as you’ve fixed it. If it’s a small leak, check the prv and radiators first.
 
CBW said:
Well keep an eye out, if it stays the same - bonus, as you’ve fixed it. If it’s a small leak, check the prv and radiators first.
Click to expand...

Is the PRV a diy job? I think there may be a tiny leak from the nut that is behind it. I haven't seen it before cos it evaporates on the heat of the pipe. The PRV appears to be a fairly cheap part; is it a straightforward install?
 
Checking the PRV is a diy job, to replace it isn’t. If you’re able to, tie a bag around the copper pipe outside, if it has water in by the morning, then it needs checking out.
 
Update: Ok, so I replaced the filling loop and all was good, much better than before.

However, recently, probably since the temperature dropped (and this may be a sheer coincidence) from an average of 10-12 degrees down to 3-6 degrees, I have been losing pressure like before. Regular shutdowns with A15 in the mornings. Re-pressurise to 1.5bar and then it drops down to about 0.7 or 0.8 fairly quickly, and then that doesn't seem to be enough to sustain it overnight.

So, back to the drawing board. Strange how it seemed to be ok for a while
 
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