I have a natural gas condensing boiler (Ideal Minimiser SE80).
I have the boiler thermostat set near to its minimum to encourage
The boiler produces a realy big plume of water vapour but I have never
noticed any water coming out of the condensate drain pipe.
There is, however, a constant drip from the tip of the flue.
Is this normal?
I don't know about your specific model. However, many condensing boilers
have a syphonic trap for the condensate. Rather than coming out as drips,
about a litre or so will be released in one big hit. This helps prevent
freezing of the pipes, as the quantity tepid water won't freeze on contact
like the drips will. You might have a boiler with such a trap and might not
have been watching when this rather infrequent event happens.
Err, you set the boiler low to encourage condensing mode.
If the return water temperature is over 55C, then it won't operate
in condensing mode, and I would expect exactly what you describe.
I don't know your boiler, but normally the flue of a condensing
boiler is installed so the water runs back inside the boiler.
Sounds like the installer has installed it as would be done for
a non-condensing boiler.
On 27 Jan 2004 05:00:47 -0800, email@example.com (David) wrote:
This sounds as though the flue has not been installed correctly.
Normally, condensing boiler flues are arranged to slope backwards
towards the boiler at a slight angle so that condensate that does
settle in the flue flows to the condensate trap.
There are two issues if it doesn't do that:
- The condensate is mildly acidic and will affect masonry if it drips
- If there is no liquid condensate in the trap then flue gases can
escape via the drain outlet. If this is in the house then you will
get fumes there as well, normally. You don't want that.
I would check the manufacturer's web site and technical department and
ask them if slope on the flue is required. It should be corrected if
That is good, yet Ideal say run the boiler at 80C, but ignore this. I'm
sure this so condensate is not produced, as too much in the heat exchanger,
if not serviced correctly, or on time, can cause a pool in there also. If
the flame detection electrodes have some crud on them, they will get wet due
to condensation, then the burner will lock out. All you do is turn off the
burner at the boiler and start again. Second time it usually works because
the fan dies out the crud. This usually means the boiler needs a service
and give the heat exchanger a "good" clean. They overcome this by a new
board that tries 3 or 4 time to light the burner before giving up. I have
the new updated board and all is fine.
With these boilers you "must" clean them once a year. And you must clean
the fins inside the heat exchanger using a plastic tie-wrap to clear the
space between the fins, especially at the bottom near the round burner.
This is a little time consuming, but worth it. Best buy a small brush to
get inside the round heat excahnger (sqaure onnthe outside). When replacing
the burner make sure you get the large O ring fitted properly otherwise
condensate water will leak onto the electronic board below.
I have a Minimizer. A good simple and reliable condensing boiler, but you
have to know its little points.
This boiler has an upwards burner. It is not v good at collecting
condensate and putting it in the drain, so most is left in the gasses. The
big plume can be very thick. Have the flue through a chimney and effect is
No. The flue is not slanting back to the boiler. Get it fixed or the flue
will corrode. No wonder little is going into the drain.
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