Bathroom hot water towel rail keeps losing water level

[Slizza786]

Hi,

Couple general pointers to mention which might help someone answer:

- S plan system with water cylinder in first floor landing and boiler on ground floor in WC
- The bedroom & ensuite with the towel rail is slight higher than the first floor. I have a garage where the top was converted to have the bedroom making it slightly higher than the first floor.
- Hot water towel rail is in the en suite which is the highest water rail/radiator in the house being vertical. There is a gas radiator in the same bedroom (wanted to mention this point incase it has an impact).
- The towel rail gets hot when either the hot water is turned on or the heating is turned on, whichever one comes on first.

The problem I am facing is my towel rail gradually loses heat from the top and eventually this continues down the rail. I haven't given it a chance to see if the whole rail eventually loses heat as I generally bleed it every 2-3 weeks. Within 2-3 weeks, the first 1-3 bars lose heat. I am not sure if it is because it is the highest rail/radiator in the house so is affected by gravity? It's the only one where I have to regularly bleed and the rest of the radiators in the house (include the radiator in the same bedroom) remains hot throughout.

Does anyone know why I am having to regularly bleed it?

 

[endecotp]

I am not sure if it is because it is the highest rail/radiator in the house so is affected by gravity?

Yes.

Does anyone know why I am having to regularly bleed it?

Air is getting into the system somehow. Others will have suggestions about what's the most likely cause.

Is it a sealed system, or is there a header tank?

 

[CountryFan]

Check for leaks on the radiator bleed vents, blanking plugs, valve connections and pipework where accessible. All of them ideally.

 

[Slizza786]

Yes.



Air is getting into the system somehow. Others will have suggestions about what's the most likely cause.

Is it a sealed system, or is there a header tank?

It's a vented system if that helps?

 

[Madrab]

If the CH is open vent (OV) then there is no real way to monitor the system to see if it's leaking, i.e. if it was sealed then the pressure gauge could be monitored. All that can be done is look for leaks @ valves and any exposed pipe joints.
Alternatively if it is OV then put the system on both heating and HW and then if you can check the small cistern (F&E) that may be in the attic, that A - it has water in it and B - check for any water coming out of the pipe that should run up, over and into the cistern, that's called pumping over and can introduce excess air into the system - (unless it's a combined Feed and Vent but that's another story)

If that rad heats up regardless of whether it's heating and hot water then that usually means it has been cut into the system pipework before the zone valves, lazy work but not exactly a major concern.

As suggested, air in any CH system will always find its way to the highest point, invariably that's the towel rail, some air is ok and bled ever now and then isn't an issue, if it's losing 2-3 towel rails every couple of weeks then the airs coming from somewhere.

Also need to try and find the cause as the F&E cistern will be making that water up every time the rad is bled and that's introducing fresh water into the system and that can dilute any inhibitor in there and accelerate corrosion. Get some some inhibitor into the cistern (100ml) every time you go to bleed the rad until is sorted.

 

[Johntheo5]

Next time you vent air out of it until you get a dribble of water which should be done with the Boiler off, start up the system&boiler and then open the vent, if no water then comes out, shut down the boiler and see if water then re appears, if so, its pulling a slight vacuum at the towel rail.