Keep having to bleed the top radiator (a rack type bathroom rad) and
others on the top floor in our system every day to get them working
properly - it's a large system (17 rads) over three floors with no
header tank. Where could air be getting in and what's a systematic way
of eliminating it?

One clue may be that sometimes there seems to be no pressure in the top
one although we replaced the pump recently.

thx

E.

On Jan 27, 12:01 pm, eastender wrote:
Keep having to bleed the top radiator (a rack type bathroom rad) and
others on the top floor in our system every day to get them working
properly - it's a large system (17 rads) over three floors with no
header tank. Where could air be getting in and what's a systematic way
of eliminating it?

One clue may be that sometimes there seems to be no pressure in the top
one although we replaced the pump recently.

thx

E.

airlock(s) lower down?

JimK

In article
s.com, JimK scribeth thus
On Jan 27, 12:01 pm, eastender wrote:
Keep having to bleed the top radiator (a rack type bathroom rad) and
others on the top floor in our system every day to get them working
properly - it's a large system (17 rads) over three floors with no
header tank. Where could air be getting in and what's a systematic way
of eliminating it?

One clue may be that sometimes there seems to be no pressure in the top
one although we replaced the pump recently.

thx

E.

airlock(s) lower down?

JimK

The gas within .. Hydrogen caused by the water breaking down. See if you
can get some of the bleed gas in a paper bag then set light to it if it
goes !! PoP !! then its Hydrogen..

All the usual disclaimers apply abaht not blowing yourself up etc;!...
--
Tony Sayer

On Jan 27, 6:01*am, eastender wrote:
Keep having to bleed the top radiator (a rack type bathroom rad) and
others on the top floor in our system every day to get them working
properly - it's a large system (17 rads) over three floors with no
header tank. Where could air be getting in and what's a systematic way
of eliminating it?

One clue may be that sometimes there seems to be no pressure in the top
one although we replaced the pump recently.

thx

E.

What is boiler pressure, do you fill it cold till water comes out,
then you have a leak, do you have an auto fill valve. Look for a leak.

In an earlier contribution to this discussion,
eastender wrote:

Keep having to bleed the top radiator (a rack type bathroom rad) and
others on the top floor in our system every day to get them working
properly - it's a large system (17 rads) over three floors with no
header tank. Where could air be getting in and what's a systematic way
of eliminating it?

One clue may be that sometimes there seems to be no pressure in the
top one although we replaced the pump recently.

thx

E.

You say that there's no header tank, so presumably it's a non-vented
(pressurised) system?

Where is the filling loop and pressure gauge - and what is the system
pressure when cold? If the gauge is at the lowest level, and there are three
floors, the static fill pressure should be 1 bar or more to ensure adequate
pressure on the top floor (there will be at least half a bar static pressure
drop between ground floor and top floor).

I don't think the pump's replacement is relevant because you shouldn't bleed
the system with the pump running, anyway.

Is there any inhibitor in the system? If not, there's a distinct possibility
that the 'air' which is collecting in the radiators is, in fact, hydrogen -
resulting from corrosion which is taking place inside the radiators.
--
Cheers,
Roger
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On 27 Jan, 12:01, eastender wrote:
Keep having to bleed the top radiator (a rack type bathroom rad) and
others on the top floor in our system every day to get them working
properly - it's a large system (17 rads) over three floors with no
header tank. Where could air be getting in and what's a systematic way
of eliminating it?

One clue may be that sometimes there seems to be no pressure in the top
one although we replaced the pump recently.

thx

E.

When you say you have no header tank do you mean you have a "sealed"
system or is it using a Primatic (spit!) cylinder.
Also does your pump "push" the water round from the boiler or does it
"pull" it back from the radiators?
Did the problem present itself after your new pump was fitted?

"cynic" wrote in message
...
On 27 Jan, 12:01, eastender wrote:
Keep having to bleed the top radiator (a rack type bathroom rad) and
others on the top floor in our system every day to get them working
properly - it's a large system (17 rads) over three floors with no
header tank. Where could air be getting in and what's a systematic way
of eliminating it?

One clue may be that sometimes there seems to be no pressure in the top
one although we replaced the pump recently.

thx

E.

When you say you have no header tank do you mean you have a "sealed"
system or is it using a Primatic (spit!) cylinder.
Also does your pump "push" the water round from the boiler or does it
"pull" it back from the radiators?
Did the problem present itself after your new pump was fitted?


The pump does not create pressure - think of it more correctly as a
"Circulator"

In article ,
"John" wrote:


The pump does not create pressure - think of it more correctly as a
"Circulator"

Indeed. Thanks for all the replies - plenty to go on although I think
hydrogen is unlikely.

E.

"cynic" wrote in message
...
On 27 Jan, 12:01, eastender wrote:
Keep having to bleed the top radiator (a rack type bathroom rad) and
others on the top floor in our system every day to get them working
properly - it's a large system (17 rads) over three floors with no
header tank. Where could air be getting in and what's a systematic way
of eliminating it?

One clue may be that sometimes there seems to be no pressure in the top
one although we replaced the pump recently.

thx

E.

When you say you have no header tank do you mean you have a "sealed"
system or is it using a Primatic (spit!) cylinder.
Also does your pump "push" the water round from the boiler or does it
"pull" it back from the radiators?
Did the problem present itself after your new pump was fitted?


Does your boiler have a filling loop and pressure gauge? If so, follow the
instructions to bring it up to pressure after bleeding - then repeat.