Combi boiler condensate drain - just dripping down an outside wall.

is it a condensate drain or pressure relief valve outlet?

NT

I am assuming condensate drain, but as you say it could be a non- condensing boiler and that could be the pressure relief valve outlet.

Testing so far not looking good; hot water was working but first test of CH seems to show that the pump runs, the indicator lights come on, but the burner doesn't fire up.

Not looking like a pristine system.

I will be searching for a manual but last time I looked I didn't get very far. Need a model number as well which isn't anywhee obvious.

Cheers

Dave R

...

Pressure relief valve letting through. Radiator circuit depressurised.

Fill valve may also be letting through, causing the system to go over-pressure, blow off, go under-pressure, etc on a cycle over hours or weeks.

Could also be the diverter valve diaphragm failing to return to rest (CH position).

A quick google suggests these were crap boilers ten years ago :-)

Owain

Model is Radiant RSF 20 E.

Looks as though it was installed in 2000.

After a bit of confusion which I think was due to the pilot light going out I managed to get the heating running. It seems to work. :-). I am online manual surfing and have found a couple of sites, but so far I haven't been able to establish if it is a condensing boiler.

The blinken lights on the front seem to indicate that pressure is fine so it may not be a leak from the expansion whatsit (but where is the outlet for the expansion valve if this isn't it?).

Anyway, off out for a while.

I would prefer the dripping to be condensate as it seems easier to sort.

Cheers

Dave R

If it is condensate which is acidic then I would expect the exit point to be clean, maybe even shiny. If it is the pressure relief outlet (more likely) then the exit would more likely to show limescale of some sort or greenish from copper corrosion. This suggests a constant need to repressurise, which your relative will soon be aware of. This implies that there is little or no anti-corrosion inhibitor left which is bad news for all the rads and other non-copper parts.

NT

Condensing combis have a condensate drain and a PR valve outlet, remember. Condensate drains are usually plastic though, so this sounds like a non-condensing combi with a leaking PR valve to me.

What does the pressure guage read?

This house had a combi in 1992. Admittedly I think they were a relatively new thing then...

Sounds like the pressure relief blow off pipe (condensate drains are not run in copper, and should not go straight outside in a narrow pipe).

Its probably telling you the pressure relief valve is letting by - either because the system pressure is too high, or the filling loop is permanently on or also letting by. Most likely though is the valve is full of crud and not reseating correctly.

See my comments above. You need to establish if it is a condensate pipe

- chances are its not. If it is, it needs joining to drainage inside the property where it is protected from freezing.

If you need manuals for Radient boilers, I have the following ones:

Directory of \Boiler Manuals\Radiant Bruciatori

let me know if any are of use.

Looking at the manual for the RSF 30 E, its not.

Looking at the SEDBUK database:

says non condensing as well.

Unless you have a leak between the primary and secondary sides of the

Yes, if it was condensing there would have to be two drains.

It looks as though the boiler has been leaking over an extended period given the staining down the wall below the copper pipe.

However the boiler says that the pressure is O.K. (nothing as fancy as a gauge, just a red light for low pressure, one for 1 bar and one for 1.5 bar). The 1 and 1.5 are both lit.

so it looks as though something is maintaining the system pressure despite the leaks.

Possibly, as suggested, the pressurising loop is permanently open?

Noted that this would not maintain any inhibitor in the system.

The boiler is noted as needing replacement but I'm wondering if at the moment the fact that it is working is enough to justify leaving it alone and keeping a wary eye on it.

Cheers

Dave R

That alas does not sound like it would tell you when the pressure is > 3 bar... too much pressure being the issue here rather than too little.

It could be as simple as a failed (or run out of air) expansion vessel. That would result in the pressure rising excessively every time the system got hot, and water would be vented outside. If the filling loop is open then it would auto reset.

You can check if the valve is still letting by - attach a plastic sandwich bag over the blow off pipe with a rubber band and see if it collects any water over a day or so. If you suspect the pressure vessel, then you can make a stopgap one by bleeding some water from a rad and leaving a pocket of air in the top of it.

Thanks - good advice.

My priority now has switched to the kitchen waste pipe.

Photos and grumbles to follow shortly I hope. Working away from home so not 100% sure I can post pictures on the Wiki. All my useful bits and pieces are probably sitting next to the PC at home.

However, onwards and upwards!

Cheers

Dave R

P.S. Moved flat contents to house in 7.5 tonne truck on Saturday and realising that I am no longer 25; or even 40. :-(

This is looking up at the copper pipe sticking out of the wall.

This is in the category of "less broken than some other things".

Cheers

Dave R

Likely it's not had any inhibitor in it for years.

NT