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Isolating Valve Problem (Read 1122 times)
Phil the Fluter
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Re: Isolating Valve Problem
Reply #9 - Apr 6th, 2018, 11:52am
 
Today, I thought I'd have a go at replacing the faulty stop valve on the filling loop.

Having shut off the heating flow, the heating return and the cold water inlet on/off valve, I drained the boiler via the drain off point.

I removed the flexi pipe of the filling loop and opened the faulty stop valve.

A little bit of water came out, then a pause, then a little bit more water, and then another pause, then a bit more water and then a steady flow of water emerged.

Having already drained the boiler via the drain off point, I wasn't at all sure where this "new" water was coming from.

Not wanting to empty the local reservoir (the worst case scenario!), I closed the stop valve and didn't proceed with the operation.

Should I have let this water flow until it stopped flowing, and then proceeded to replace the stop valve?

Advice much appreciated.
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Phil the Fluter
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Re: Isolating Valve Problem
Reply #8 - Feb 25th, 2018, 1:26pm
 
Thanks for the reassuring reply.
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thescruff
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Re: Isolating Valve Problem
Reply #7 - Feb 25th, 2018, 9:58am
 
In this case, they are both the same, although stop valve would be the better terminology.
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Phil the Fluter
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Re: Isolating Valve Problem
Reply #6 - Feb 24th, 2018, 12:31am
 
I've decided to replace the faulty valve described above.

The manual describes the valve as a "stop valve". Is that the same thing as an isolating valve?

The faulty valve certainly looks for all the world like an isolating valve (with a black lever).

The Baxi manual shows the filling loop system  thus:  DHW mains inlet > stop valve > double check valve  > filling loop > stop valve > CH return

The faulty valve is the one attached to the CH return.

Is it simply an isolating valve?

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thescruff
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Re: Isolating Valve Problem
Reply #5 - Feb 9th, 2018, 12:39pm
 
Not being used adds to the problem as the stick. They are roughly off when the handle is horizontal to the pipe, but you have to allow for ware the same as the old washer type valves that needed re-seating.
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Phil the Fluter
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Re: Isolating Valve Problem
Reply #4 - Feb 9th, 2018, 10:35am
 
Sorry, I must've explained the situation badly.

The horizontal position is NOT off: the valve closes fully as the handle approaches the horizontal position but, as it reaches the horizontal position, it opens again – not fully but certainly significantly.

The valve has not been subjected to much used during its lifetime: it's probably only been used a handful of times since the boiler was installed.
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Re: Isolating Valve Problem
Reply #3 - Feb 9th, 2018, 1:03am
 
Sounds about right, it's only a ball with a hole drilled through it, as you say, horizontal is off, the handle should stop it going past horizontal unless it's worn.
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Re: Isolating Valve Problem
Reply #2 - Feb 8th, 2018, 12:58pm
 
Thanks for the reply.

As an experiment, I've just removed the plastic handle and tried opening and closing the valve using a pair of pliers on the brass fitting.

The situation is exactly the same no matter whether I use the plastic handle to operate the valve or work directly on the brass fitting.

In the fully open (handle vertically down) position, the valve is fully open and as I rotate the handle clockwise towards the horizontal position, the valve closes fully - as one would expect. However, as the handle reaches the horizontal position, the valve opens again – not fully but quite substantially.
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Re: Isolating Valve Problem
Reply #1 - Feb 8th, 2018, 11:52am
 
Likely to be the handle spinning on the shaft.
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« Last Edit: Feb 8th, 2018, 11:53am by thescruff »  
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Phil the Fluter
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Isolating Valve Problem
Feb 7th, 2018, 10:42pm
 
The filling loop on my combi boiler has a check/isolating valve at one end and an isolating valve at the other (furthest from the cold water feed).

The isolating valve seems to be wide open in the fully-closed position (water will flow through it as if it wasn't there) but, if I turn the lever a little way away from the fully-closed position, the valve closes perfectly.

I'm thinking of giving the l lever a good wiggle to see if I can flush out any impurity that might be preventing it closing properly.

Any comments or suggestions would be gratefully received.

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