Just a thought - is the pressure much higher than an open vented system with
a tank in the loft?
Thinking of changing mine and wondered if some of the radiators would be at
|!"visionset" <sp...@ntlworld.com> wrote in message
|!> Okay, several months down the line I'm getting sick of filling up and
|!> diluting the additive in my combi system.
|!> New combi boiler in the summer, changed from vented to sealed, fair bit of
|!> old pipework and rads. All the rad valves are new at various times within
|!> the last 8 years. I'm guessing there are leaks at the new pressure though
|!> nothing is visible and upstairs pipework is concealed. I suppose the
|!> leaks are so tiny that the water evaporates on the surface making it
|!> harder to trace. Maybe when the rads aren't on come the spring it will be
|!> more obvious. Any one know how I can track down the source?
|!> Mike W
|!Just a thought - is the pressure much higher than an open vented system with
|!a tank in the loft?
Yes pressure goes up from less than a bar to 1-2.5 Bar
|!Thinking of changing mine and wondered if some of the radiators would be at
Only if they are very corroded. I used inhibitor in my radiators with the
vented system and despite having to flush out a lot of black crud, the old
radiators are fine.
Dave Fawthrop <dave hyphenologist co uk>
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Yes 2 to 3 times. You hijack my thread why don't you ;-)
My experience leaves me dubious about combis (if that's what you're
planning) There is one heck of a lot to be said for keeping things simple.
Despite appearances a Combi system is much more complex, and hence
expensive, more likely to go tits up and more expensive when it does. Suits
my house, but never again. I'd say the only place for a combi is a new build
or complete renno (inc 1st fix wets) with 1 bathroom.
Does a sealant additive do what it says on the tin?
If this was a high vacuum system, I'd pump it down, connect a
mass-spectrometer, then spray helium round any suspect pipe areas.
When you get a spike of helium coming through the mass spec, you've
found a leak.
Unfortunately, this is probably not practical, unless you happen to have
a source of high vacuum, a mass spectrometer, and some way to bake out
the existing water in the piping.
In my previous career as an analytical chemist I could of at least borrowed
a pump and sampled a makeshift port and taken in the sample to work. As a
programmer I can't think of any software I could write to help me!
Try adding a UV dye to the water, turn the lights out and go hunting
with a UV torch.
I wonder if the stuff sold for PC modders would be OK
Or something really stinky. Ex-chemists should be good at this.
Drain the system then connect a car footpump and check with soapy
water at all the joints?
Is it possible to put a food dye, or even better a fluorescent dye into
the system, turn down the temperature and leave it for a few hours
pumping water throughout the system by making heating and water demands?
My thoughts are that by reducing the temperature, you will loosen any
slack joint and enable it to leak slightly.
Then go over the pipe work looking for the dye/fluorescent marker. (A
fluorescent black light does not cost all that much. See Maplins site.)
After you find/don't find any leak, flush the system out and use as normal.
I could be wrong, but I hope this helps.
> My experience leaves me dubious about combis (if that's what you're
> planning) There is one heck of a lot to be said for keeping things simple.
> Despite appearances a Combi system is much more complex, and hence
You seem to be confusing sealed systems with combis. Most boilers these
days use a sealed primary, not just the combis.
| Internode Ltd - http://www.internode.co.uk |
| John Rumm - john(at)internode(dot)co(dot)uk |
Tie a clear plastic sandwich bag round the outlet and see. If there is a
leak the bag will accumulate water.
If you've eliminated the PRD and are sure it really is a leak in the
pipework then go round all the rad joints feeling for damp. If you're
having to top up several times a year you may well feel dampness from the
leak even if it tends to evaporate before it can accumulate and drip off
visibly. Obviously test joints to the boiler and elsewhere also.
Compression joints are the main culprits here.
As you suggest, doing it when system is cold makes it much more
likely you will see the leak. Trouble is the pressure will also
be lower, leak may reduce or stop, so increase the pressure up
to the normal pressure when hot (system all turned off, obviously).
Then go around a few hours later checking all the pipework, rads,
etc for leaks. I installed a new system 5 years ago, and I've had
two of the rubber O-rings on radiator blanking plugs fail, which
I tracked this way. The leak wasn't enough that I needed to top it
up, but it annoyed me there was any leak at all. Other places to
check are the pipework inside the boiler casing, and hardest of
all, a leak in a condensing heat exchanger, because you can't
usually get to it. Check PRV isn't leaking.
To let the pressure down to normal afterwards, draw off water from
a radiator bleed valve or drain valve. Don't use the pressure relief
value as you can end up with debris stuck in it which makes it leak.
[email address is not usable -- followup in the newsgroup]
Remember to take the plastic tops of rad valves & TRVs and check for
signs of leakage around the spindle , seepage can evaporate away
before showing up on the visible body of the valve.
> Remember to take the plastic tops of rad valves & TRVs and check
> for signs of leakage around the spindle , seepage can evaporate
> away before showing up on the visible body of the valve. Robert
To check rad valve spindles for leakage wrap a tissue
around each one. The tissue may not be damp at time of
checking but will generally show a telltale stain,
left behind from water that has evaporated.
And if the valve is wet, a light blue tissue will show it up better than
a white one.
Toilet paper - especially cheap stuff, will shrink and crumple when it
gets a spot of water on it.
That will because it is designed to dissolve in water.
Okay, okay, okay, but what of the Fernox Leak Sealer additive, anyone used
it? Does it do what it says?
> Ian Stirling wrote:
> > Toilet paper - especially cheap stuff, will shrink and crumple
> > when it gets a spot of water on it.
> That will because it is designed to dissolve in water.
Arrgh! Memories of Bronco bogpaper. As scratchy as
hell, and probably even aqua regea wouldn't dissolve it.