A maddening central heating problem

[Grey_Area]

Turning to PH for some assistance, as it's currently coming up to 3 am and I'm just not able to figure this one out.
At this time in the morning for the last few days that I've been awake anyways, the master bed central heating radiator is sat here happily making what could be best described as a type of plinking sound; imagine if you would a small internal leak, and you can hear it dripping internally.
The issue is, being a large finned aluminium radiator, it's amplifying he sound across 14ft of bedroom, so I can clearly hear it; and it's maddening.
System is an open vent, on a Y plan arrangement, small loft header tank type.
What it isn't, or doesn't appear to be is requiring bleeding, just done that and absolutely no air whatsoever , the 3 port valve is red hot, so I thought it might be clicking away trying to drive home; disconnected that and it's sitting in an airing cupboard on the floor.
There's no call from the programmer for heat, all pipe works cold ; boiler shows about 21 degrees on the front panel for water temp, and the central heating pump is not running at all.
I've turned off the lock shield, wound down the TRV, checked other radiators, and still it persists..

Does anyone have any ideas on what else I can look for, before I'm driven mad at expectedly 3,am tomorrow, as the radiator is quiet at all times during the day otherwise...

TIA.

Edited by Grey_Area on Friday 29th December 03:39

[colin_p]

It probably has some air in there, somewhere.

I had a similar problem with a few, very tall, column rads.

What solved it for me was fitting some automatic bleed valves to rads in addition to the manual bleed nipps.

https://aladdin-products.co.uk/aladdin-autovents-r...

[.:ian:.]

Mine makes a clicking noise which is almost certainly pipes or the rad rubbing against something as they expand and contra t, this happens mostly when heating up, but also as they cool down.

Only goes on for a minute after the heating goes off though.

Hot 3 way valves can be a symptom of the "water off" holding voltage, https://wiki.diyfaq.org.uk/index.php/Three_port_mi...

[Grey_Area]

Thanks Both.

Definately not heating/cooling cycle, as its far to regular, think of a metronome; theres an internal plinking just less than once a second, for about an hour or so...this morning anyway, other mornings i've woken up its been around 3 still, but no idea how long.
Heating/cooling cycles tend to be irregular, and only a handful of minutes in my experience here, central heating goes off at 9pm, so it would be a bit long to still be plinking away at 3 am some 6 hours later and thats why its a frustrating thing, no other radiator is showing the same symptoms

I dont think its an airlock, again for the reasons above... and when i bled it at 3 this morning, no air at all, came straight out slight colour due to the inhibitor, but otherwise clear and air free.

I'll take a look at the airbleed device, as I think thats damned handy anyway, so many thanks for the link,

Thanks for the Wiki link. I'll be doing some reading later. This might push me over the edge to go for a S plan system later in the year..

Cheers.

Edited by Grey_Area on Friday 29th December 09:32

[B'stard Child]

.:ian:. said:

Hot 3 way valves can be a symptom of the "water off" holding voltage, https://wiki.diyfaq.org.uk/index.php/Three_port_mi...

I found that out with the newly installed 3 port valve on my CH/HW Y plan - the old one 40 years old never got hot (rotary type but kinda clockwork in operation)

New one if the CH is left on the motor body gets very hot. My solution is at the end of every heating cycle I've programmed 1 min of HW - the boiler never fires for that and it puts the 3 port valve back to the HW rest point where it consumes no electricity and remains cold

[Grey_Area]

B'stard Child said:

.:ian:. said:

Hot 3 way valves can be a symptom of the "water off" holding voltage, https://wiki.diyfaq.org.uk/index.php/Three_port_mi...

I found that out with the newly installed 3 port valve on my CH/HW Y plan - the old one 40 years old never got hot (rotary type but kinda clockwork in operation)

New one if the CH is left on the motor body gets very hot. My solution is at the end of every heating cycle I've programmed 1 min of HW - the boiler never fires for that and it puts the 3 port valve back to the HW rest point where it consumes no electricity and remains cold

Simple yet effective, so thank you for the advice.

[B'stard Child]

Grey_Area said:

B'stard Child said:

.:ian:. said:

Hot 3 way valves can be a symptom of the "water off" holding voltage, https://wiki.diyfaq.org.uk/index.php/Three_port_mi...

I found that out with the newly installed 3 port valve on my CH/HW Y plan - the old one 40 years old never got hot (rotary type but kinda clockwork in operation)

New one if the CH is left on the motor body gets very hot. My solution is at the end of every heating cycle I've programmed 1 min of HW - the boiler never fires for that and it puts the 3 port valve back to the HW rest point where it consumes no electricity and remains cold

Simple yet effective, so thank you for the advice.

No problem at all - happy to share

PS I'm a very simple person

[B'stard Child]

On the plinking sound issue mentioned by the OP - have the mounting brackets for the rad still got the plastic inserts that the rad mounting points sit on or is it "metal to metal"??

They do a really good job of stopping the clicking sounds as rads heat up or cool down.......

When they are missing you can get a lot of noise from a rad

[Regbuser]

When the radiator was hung on the wall, were little plastic shims used? Are the wall brackets true, i.e. no slight twist between centres?

Any slight non-centredness can cause noise due to expansion and contraction of the rad against the brackets, and on a large radiator, may persist for some time.

[Grey_Area]

Radiator was hung with the little plastic bits, there's enough movement that its all seated nicely on the brackets.

Its the fact that some 6 hours after the heating goes off I am unable to fathom, combined with the utter regularity of the "beat" it is so damned regular its untrue, with heating/cooling, its irregular , and on my system is around for 5-10 minutes at the most; this is just as if someone had planted a bloody metronome in there....

[Regbuser]

Okay, is it doing it now?

Is the sound internal, or possibly external?

[Grey_Area]

Regbuser said:

Okay, is it doing it now?

Is the sound internal, or possibly external?

Nope, nothing sounding at all..

its as if there's a programme running in the middle of the night, but there's not... programmer most definately only has two slots, 5-7:30 am, and 17-21:00

Its one of the resons i thought i'd ask on PH, I am utterly stumped, and was begining to get side tracked into it must be after its run and needing to be bled, or after its run and there's a programme keeping it going, or the 3 port valve is clicking ( had that before and very rhythmic )

Presently, theres absolute stillness... pity I dont sleep during the day, because its something I can hear at night as a light sleeper..

Thanks anyways.

[B'stard Child]

Grey_Area said:

Nope, nothing sounding at all..

its as if there's a programme running in the middle of the night, but there's not... programmer most definately only has two slots, 5-7:30 am, and 17-21:00

Its one of the resons i thought i'd ask on PH, I am utterly stumped, and was begining to get side tracked into it must be after its run and needing to be bled, or after its run and there's a programme keeping it going, or the 3 port valve is clicking ( had that before and very rhythmic )

Presently, theres absolute stillness... pity I dont sleep during the day, because its something I can hear at night as a light sleeper..

Thanks anyways.

The boiler isn’t in a garage and it’s a frost stat kicking in - the 3 port valve open to CH and as a result you get a very small flow of heat to the rad before the boiler frost stat kicks off?

[Grey_Area]

B'stard Child said:

Grey_Area said:

Nope, nothing sounding at all..

its as if there's a programme running in the middle of the night, but there's not... programmer most definately only has two slots, 5-7:30 am, and 17-21:00

Its one of the resons i thought i'd ask on PH, I am utterly stumped, and was begining to get side tracked into it must be after its run and needing to be bled, or after its run and there's a programme keeping it going, or the 3 port valve is clicking ( had that before and very rhythmic )

Presently, theres absolute stillness... pity I dont sleep during the day, because its something I can hear at night as a light sleeper..

Thanks anyways.

The boiler isn’t in a garage and it’s a frost stat kicking in - the 3 port valve open to CH and as a result you get a very small flow of heat to the rad before the boiler frost stat kicks off?

No unfortunately, boiler is indoors in a "pantry" so well protected, and the frost protection is set to 5 degrees, tested that by putting the wireless stat in the fridge, that brings the boiler on when the temp drops, and it cycles on a low setting and goes off when the temp recovers to normal.

Nice thought though, I think i'll dig into the programmer settings, its a Honeywell ST 9400C from memory.

Goes off to have a play....

Thanks

[B'stard Child]

When do you heat your hot water - time slots like ch or on demand when the tank stat calls for heat?

[Grey_Area]

B'stard Child said:

When do you heat your hot water - time slots like ch or on demand when the tank stat calls for heat?

For about one hour prior to the CH on a timed basis; at this time of year it's 4-5pm, central heating then comes on straight after.
Tank stat controls water temp, and the boiler return and wireless room stat controls the CH temps.
Boiler is a vented Vailant ecotec plus 418.

[James6112]

I saw you’d tried winding down the trv

Maybe worth removing the trv head for a night, to eliminate that for certain?

[Gtom]

I would say it’s something to do with the header tank?

I can’t explain why it’s doing it but the plinking would be like a drip from the ball valve. Maybe there is a small leak on the system and it’s just topping at that time.

[Grey_Area]

James6112 said:

I saw you’d tried winding down the trv

Maybe worth removing the trv head for a night, to eliminate that for certain?

Thanks, tried that, and winding down the lock shield; made no difference unfortunately
Thank you though.

[Grey_Area]

Gtom said:

I would say it’s something to do with the header tank?

I can’t explain why it’s doing it but the plinking would be like a drip from the ball valve. Maybe there is a small leak on the system and it’s just topping at that time.

Interesting; I might try to setup a Timelapse, see what that shows...
I'd still like to know though why it seems to be only apparent on just this radiator .. the others upstairs are the same design, just slightly smaller ..
Now I need to see if my old iPhone 6 will take a charge and do some time lapse..

Thank you.