I'm trying to bleed my radiator in my new apartment and I've found that the
re's no bleeder valve. I have 3 rads in the apartment which was recently re
-furbished; all of them have the same problem. They'll heat the first two c
olumns of a large column radiator and remain at a low temperature but not f
low across the entire radiator. I may be wrong about the initial issue (ble
eding) but I don't know how to proceed since there is no bleed valve.
That white knob in your first picture would have to be it. I expect
it's an automatic air vent; so you have to have the literature that
comes with it to see how to open it manually.
I can't read the name on the front of the knob, but if it says Danfoss,
that's a well known Danish manufacturer of hot water heating system
If you can take that picture down to any local heating contractor, he
should be able to tell you how it works.
On Sunday, October 13, 2013 11:44:15 PM UTC-4, nestork wrote:
As Bud pointed out, it's the thermostat for the radiator. Very
common in Europe. There is a pipe on both sides of it, you
can see it in one of the pics, but not in most of them.
Whether they have a bleed function as well, IDK. He could
find the make/model and google the instruction sheet.
If it doesn't have a bleed, then again, I agree with Bud,
it's a rental, so tell the landlord about the problem, it's
Or even to whatever their version of HomeDepot is,
plumbing supply, etc.
On Monday, October 14, 2013 10:09:14 AM UTC-4, bud-- wrote:
Do they still use one pipe steam in Europe? I haven't seen that system in
a long time.
That knob is a thermostat. It never made sense to me to put the thermostat
on the heat source, but when we lived in Europe our radiators all had them
and they worked okay. They did have bleed valves on the end opposite the
thermostat. I never got much air out of them though. But I did have to ta
ke off the thermostat periodically. There's a little brass plunger that go
es into the valve. They stick especially if there's hard water. You have
to grab them with pliers and work them in and out a few times, then the rad
iator gets hot again.
If it's steam, what are you bleeding?
I am changing my mind. I think there is a pipe that can not be seen into
the wall at the top right. For one pipe steam the supply pipe would
probably have to be a lot bigger than what can be seen.
Likely hot water.
I did not notice that the OP comes from Switzerland. People here are
mostly from the US with some Canada and UK.
Thermostat at the radiator should be a cheap way to zone the system.
Maybe the bleed is built into the thermostat? Ask the landlord.
But if there were air in the radiator the bottom would be hot (where the
Almost all my (hot water) radiators have pipes out the ends on the bottom.
One upstairs has pipes out one end - at the top and bottom (probably
what is pictured). Sometimes it does not heat because the system
pressure falls. The heating system pressure has to be high enough to
force all the air out the air bleed. And the pressure has to high enough
for water to reach the top pipe to circulate. I suggest having the
landlord check the system pressure.
What I remember is that steam systems let air in when they cool. Else
you would pull a vacuum. An automatic air valve lets air out and closes
when hot (when steam gets to the radiator) and probably opens when cold.
Maybe that is just a one pipe steam system.
Very strange. Maybe there's a manufacturing defect in the radiators.
It seems to me, even if there is cold air in them, bleeding should not
be necessary because the steam in part of the radiator is adjacent to
the cold air and the steam should within 30 or 60 minutes heat the
cold air and humidify it and make the surface just as hot as the part
with steam. Convection.
OTOH, hot water can exist next to air that is nowhere near as hot, and
the air has to be bled. As an aside, I would think there are other
differences between steam and hot water radiators, in addition to
bleeding and number of pipes.
That was going to be my question.
Also, how tall is your building?
I agree. And In my experience here in the USA, there is no bleeding
required with steam. Maybe because the steam easily mixes with air in
the radiators and only at the start does the cold air lower the temp
of the steam. Just guessing.
There is a pressure regulator on a steam radiator that lets off excess
steam, but if part of the radiator is cold, I don't think you have
excess steam, OP.
Or if he's not around, other tenants.
Or friends with new radiators.
Or go a store which sells stuff like this and ask them how it works.
A store that only sells heating equipment would be best. At a general
hardware store, maybe no one will know.
Or the web???
And of course if these are brand new radiators with a new design,
maybe no one but the landlord can help you.
I don't know, but if it's hot water**, there should be two pipes per
radiator. I see no evidence of a hidden pipe. So it must be steam.
I dont think thermostats like the one pictured work with hot water,
that is, at least they didn't 20 years ago in the USA, the last time I
checked. The poster should tell us, how many pipes.
**The only radiators that need bleeding afaik.
Normally in a steam radiator, the steam comes in through the only
pipe. It gives off heat and gets colder and turns back into hot water
which drops to the bottom of the radiator and runs out of the radiator
through that same pipe, at the bottom of the pipe. I suppose some
might change to steam on the way down (and then go back up again), but
one can look at it as if the hot water returns to the basement where
it's heated again and turned into steam again.
On Monday, October 14, 2013 6:04:21 PM UTC-4, micky wrote:
e: > >I don't know, but if it's hot water**, there should be two pipes per
think thermostats like the one pictured work with hot water, >that is, at
least they didn't 20 years ago in the USA, the last time I I'm wrong about
no hot water thermostats. http://en.wikipedia.org/wiki/Thermostatic_Radiato
r_Valve >checked. The poster should tell us, how many pipes.
if it is steam, the valve at the top has to initally open to let the air OU
T so the steam can come in. Once the steam fills the radiator and it all g
ets hot and the valve gets hot, it closes to keep the steam from escaping.
If your radiator is slow to heat and doesn't fully get hot, it is likely t
hat the valve is not set correctly or not working.
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