A few years back whilst I had the central heating system drained down I
fitted auto bleed valves to my radiators (Aladin Autovent)

https://www.amazon.co.uk/Aladdin-Aut.../dp/B01L4P1IO6

They worked for a while.

I recently drained down the system again to remove radiators for a few
weeks to facilitate some building work. I have now re-instated the
radiators and have found that zero (out of six) auto bleed valves are
still working. This includes those on 4 radiators that have been
sitting around, fully drained for a few weeks.

Luckily I still had the manual bleed valves on the other side of the
radiator which I've used to remove the air from the system. Even with
the radiators on and running at full heat for very many hours a second
check of the radiators resulted in some air having to be removed showing
the auto bleed valves were still not working.

As a result I cannot recommend the use of the Aladin Autovent valves but
has anyone had any experience of auto bleed valves fitted to radiators
that work long term?

I do not anticipate any problem now with air entering my system until I
again drain down or remove/replace a radiator.

I do have some auto bleed valves fitted to the pipework high points that
are still working after 20+ years. These values are not suitable for
radiators and are of the type
https://www.screwfix.com/p/bottle-air-vent-15mm/34359

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alan_m wrote:


A few years back whilst I had the central heating system drained down I
fitted auto bleed valves to my radiators (Aladin Autovent)

https://www.amazon.co.uk/Aladdin-Aut.../dp/B01L4P1IO6

They worked for a while.

I recently drained down the system again to remove radiators for a few
weeks to facilitate some building work. I have now re-instated the
radiators and have found that zero (out of six) auto bleed valves are
still working. This includes those on 4 radiators that have been
sitting around, fully drained for a few weeks.

They get blocked after a time. The constant wetting & drying will
precipitate crud/scale inside them. I think the problem is common to
virtually all auto bleed valves.


Luckily I still had the manual bleed valves on the other side of the
radiator which I've used to remove the air from the system. Even with
the radiators on and running at full heat for very many hours a second
check of the radiators resulted in some air having to be removed showing
the auto bleed valves were still not working.

As a result I cannot recommend the use of the Aladin Autovent valves but
has anyone had any experience of auto bleed valves fitted to radiators
that work long term?

I do not anticipate any problem now with air entering my system until I
again drain down or remove/replace a radiator.

I do have some auto bleed valves fitted to the pipework high points that
are still working after 20+ years. These values are not suitable for
radiators and are of the type
https://www.screwfix.com/p/bottle-air-vent-15mm/34359

I have one of those above my boiler. It failed causing water to weep down
into my boiler causing a lot of damage. I believe that theyre only really
recommended for use when refilling and degassing a system for a few days.

I have a ball valve fitted below it now so that once degassed, I can shut
it off completely.

Tim



--
Please don't feed the trolls

On Thursday, 24 October 2019 21:22:18 UTC+1, alan_m wrote:
A few years back whilst I had the central heating system drained down I
fitted auto bleed valves to my radiators (Aladin Autovent)

https://www.amazon.co.uk/Aladdin-Aut.../dp/B01L4P1IO6

They worked for a while.

I recently drained down the system again to remove radiators for a few
weeks to facilitate some building work. I have now re-instated the
radiators and have found that zero (out of six) auto bleed valves are
still working. This includes those on 4 radiators that have been
sitting around, fully drained for a few weeks.

Luckily I still had the manual bleed valves on the other side of the
radiator which I've used to remove the air from the system. Even with
the radiators on and running at full heat for very many hours a second
check of the radiators resulted in some air having to be removed showing
the auto bleed valves were still not working.

As a result I cannot recommend the use of the Aladin Autovent valves but
has anyone had any experience of auto bleed valves fitted to radiators
that work long term?

I do not anticipate any problem now with air entering my system until I
again drain down or remove/replace a radiator.

I do have some auto bleed valves fitted to the pipework high points that
are still working after 20+ years. These values are not suitable for
radiators and are of the type
https://www.screwfix.com/p/bottle-air-vent-15mm/34359

--
mailto : news {at} admac {dot} myzen {dot} co {dot} uk

There are two sorts.
One has a float.
The other has a material which shrinks when it dries out (usually a washer) and swells when wet. You have to soak them in water (or let them be soaked) before they close off.
Haven't seen the latter for years though.

On 25/10/2019 10:11, Tim+ wrote:


I have one of those above my boiler. It failed causing water to weep down
into my boiler causing a lot of damage. I believe that theyre only really
recommended for use when refilling and degassing a system for a few days.

I can get to the locking caps on mine. When filling I loosen the cap and
let it auto-vent for a few days. I then screw down the cap which will
prevent water leakage if it fails. As mentioned previously I don't get
an ongoing problem with air after a few days after refilling etc.


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On 25/10/2019 10:21, harry wrote:

There are two sorts.
One has a float.
The other has a material which shrinks when it dries out (usually a washer) and swells when wet. You have to soak them in water (or let them be soaked) before they close off.
Haven't seen the latter for years though.


The Aladdin ones fitted to radiators are effectively the latter type. I
wouldn't expect them to work too well if the system were drained down
and then refilled soon afterwards as they wouldn't have had time to dry
out. In my case the radiators had been removed and drained down for a
few weeks allowing time for the valves to dry.

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mailto : news {at} admac {dot} myzen {dot} co {dot} uk

Bleeding radiators is hardly rocket science. I would rather be in control
of it than trust an automatic valve.