How to use this heated towel rail?

[parakeet]

Two valves, gas central heating.
I've learned that the two valves are likely to be:

-- Lockshield: Controls amount of hot water entering the radiator ("also ensures the operation of the towel radiator won’t impact the performance of other radiators in your home).
-- Wheel-head: Controls amount of hot water released by the radiator ("to control the radiator’s temperature"). Anti-clockwise: increase flow; clockwise: decrease flow.

But which is which in my system?

The left-hand one likes to leak some blue-green fluid since I first fiddled with them last year.

The rad is roughly above the combi boiler, which was newly installed in February.

This is the back of the house (left). All the other rooms are off to the right of this pic.

 

[Madrab]

Lockshields regulates the flow of hot water into/out of rad but is relatively tamper proof and once set for balancing should be left

Wheel head is exactly the same but can easily be turned on and off by the user.

Are they 1/4 turn valves or screw down? If they are leaking then chances are the gland may need nipped up or if they are 1/4 turn then the valves are goosed.

 

[parakeet]

Lockshields regulates the flow of hot water into/out of rad but is relatively tamper proof and once set for balancing should be left

Wheel head is exactly the same but can easily be turned on and off by the user.

Are they 1/4 turn valves or screw down? If they are leaking then chances are the gland may need nipped up or if they are 1/4 turn then the valves are goosed.

No idea, and I'm afraid I don't understand the terminology here.

Visually, they look like this on the exterior...

 

[Madrab]

Do they only twist a 1/4 of a full turn? Or can you turn them through several full turns?

 

[parakeet]

Do they only twist a 1/4 of a full turn? Or can you turn them through several full turns?

Ah - seems like they go more than 1/4. At least one turn, don't know about several.

 

[Mottie]

With them both open and the heating on, the pipe to the one that gets hot first is usually the wheel head side.

 

[parakeet]

With them both open and the heating on, the pipe to the one that gets hot first is usually the wheel head side.

Okay, so...

-- Open both fully (all the way anti-clockwise?).
-- The side that gets hottest first (wheel head) is effectively the temperature control.

?

But then, still, how would I use the two together? Where should the lock head one be placed / how to balance? ie how much water to let in?

Also -- "the pipe to the one that gets hot first is usually the wheel head side"... is this different if they were 1/4 valves?

Thanks.

 

[Mottie]

Once you know which is which, you can experiment by slightly opening the lock shield valve. As you say it’s pretty near to the boiler, I’d start by cracking it open a small amount and opening the wheel head fully. If it doesn't get hot enough, quick enough, open it a bit more until you are happy with it. Trial and error really.

 

[Madrab]

The side that gets hottest first (wheel head) is effectively the temperature control.

Not really .... with normal wind down taps all they do is slow the flow, they won't actually control the heat as such. That's controlled by the temp of water and that's set at the boiler. If you adjust the valve ever so slightly then it can slow the warm up of the rad therefore you could get a little temp control as the rad will lose heat quicker than the inflow can warm it, if you see what I mean, but it's not really meant for that. Only way that the actual temp of the rad could be controlled is using a blending system or adjust the boiler output.

The side that gets hot first is the flow but either side of the rad can be the 'wheel head' as either will slow the flow in and out of the rad. All that is usually used for really is to aid balancing as part of the whole central heating system.

 

[parakeet]

Ok, pretty confused!

So, what should I do and how should I use these, for the season ahead?

Turn them both off/closed? And then turn on one and the other? What's the appropriate mix I'm looking for? Ie. Letting in water but letting it out?

Does it flow out to (and thus feed) all the other rads in the house? Or does it just flow back out as waste?

I don't even see any way to bleed this.

In an ideal world, I would be able to put a programmable TRV on this so that it comes on only at certain times of the day. Working from home in one room, I don't really think i need to be keeping the bathroom towel rail on all day.

But I know the towel rad is supposed to have an important role in a system and apparently should normally not be closed? Nervous about getting this rad right on behalf of all the others.

 

[terryplumb]

With both valves fully open ,turn on central heating. Go to the rad and feel both pipes ,one will heat up before the other and that is the flow.
The valve on the flow side is what you will use to turn that rad on or off as you wish. The other valve is the lockshield and must be left open,to some degree ,exactly how much is a bit of trial and error . Try closing it fully ,leave the rad to cool then open it a little bit until the rad starts to heat up. And leave it in that position.
Show us a pic of the top of the rad, the air bleed valve may be under a removable cover.

 

[parakeet]

With both valves fully open ,turn on central heating. Go to the rad and feel both pipes ,one will heat up before the other and that is the flow.
The valve on the flow side is what you will use to turn that rad on or off as you wish. The other valve is the lockshield and must be left open,to some degree ,exactly how much is a bit of trial and error . Try closing it fully ,leave the rad to cool then open it a little bit until the rad starts to heat up. And leave it in that position.

Ah, okay. Left was first to heat up. Left is flow.
I have ended up putting the lock shield somewhere between open and closed, and the flow at maybe a quarter open. Sound about right?

Show us a pic of the top of the rad, the air bleed valve may be under a removable cover.

Silly me. There is a slatted hole at the top of the right-hand upright.
I just opened it up but, to my surprise, no water came out.

 

[terryplumb]

No water came out the bleed valve? Did air hiss out ? If so ,You may need to top up the system pressure.

 

[parakeet]

No water came out the bleed valve? Did air hiss out ? If so ,You may need to top up the system pressure.

No water. It definitely hissed.
That was a few hours before now. Just now, I checked the boiler - the pressure had all gone to 0 and the boiler was displaying a low-pressure warning. No hot water.
I:
-- re-pressurised to 1.6.
-- changed the towel rad knobs to a more accurate mid-point (seems like they can each turn three times in full)
-- used the wireless thermostat to specify a set-temp, to ensure the boiler would send hot water. At this point, the towel rad is the only one open in the house.
The towel rad is indeed warm now - too warm, frankly. I just turned it down another quarter-turn.
The boiler pressure is now about 2.2 when actually active (it drops when inactive).

So complicated. I'm learning that the left-hand one should control effective strength, but I'm especially anxious about proper use of the right-hand one and what it means for the rest of the system.

(The boiler is new as of February, when we also took the opportunity for the engineers to replace a couple of legs of upstairs piping with thicker-diameter pipes, due to previous pressure issues).

Thanks for the help.

 

[parakeet]

Thanks @terryplumb. Big help. Much appreciated.