Radiators not Heating Up

tristanjourney

BUFF said:

A manual valve & lockshield.

As TIW said if you have a hot water cylinder that rad heating up when CH  should not be "on" could be related.

Can you elaborate why manual valve & lock shield is recommended? I see different opinions from https://forums.moneysavingexpert.com/discussion/5154548/advice-needed-radiator-towel-rail-in-bathroom-off-hw-circuit/p1

By the way, is manual valve actually similar to thermostatic radiator valve but just require a bit more efforts to adjust?

ThisIsWeird

To answer the above first, a 'manual' valve relies on being manually controlled, by hand, and is designed for this, and should be relatively to adjust. It will only be fully off if manually turned fully off - which a by-pass radiator should not be. So, the by-pass rad's valve should always be tweaked partly open to allow a permanent level of by-pass, and left like that. Often the knobs will be removed to prevent change, or it replaced by a cap.

A TRV, on the other hand, adjusts itself according to room temp. So as the room heats up, the valve will likely close - which is not what you want.

Similar setup is used in the room that has the wall stat. These should also always be manual valves, but for a different reason; here, you want the room stat to do the temp controlling, and not a TRV. The use of the latter would 'fight' the room stat - two stats trying to do the same job, but confusing eachother.

ThisIsWeird

Ok, your  boiler programmer is set to HW 'Off'? So when and how does it heat the hot cylinder...?

tristanjourney

ThisIsWeird said:

Ok, your  boiler programmer is set to HW 'Off'? So when and how does it heat the hot cylinder...?

HW was intentionally set to off by programming the timer, because no one is currently living in the house.

The timer has HW set as OFF, and CH set as TIMED.

I've asked the gas engineer who just serviced my boiler. He said the radiator in the bathroom might be fed from the hot water supply and will be on continuously with this to warm towels. This left me more confused, because my HW timer is completely off right now. Is this hot water supply radiator the same as what you called by bypass radiator?

tristanjourney

ThisIsWeird said:

To answer the above first, a 'manual' valve relies on being manually controlled, by hand, and is designed for this, and should be relatively to adjust. It will only be fully off if manually turned fully off - which a by-pass radiator should not be. So, the by-pass rad's valve should always be tweaked partly open to allow a permanent level of by-pass, and left like that. Often the knobs will be removed to prevent change, or it replaced by a cap.

A TRV, on the other hand, adjusts itself according to room temp. So as the room heats up, the valve will likely close - which is not what you want.

Similar setup is used in the room that has the wall stat. These should also always be manual valves, but for a different reason; here, you want the room stat to do the temp controlling, and not a TRV. The use of the latter would 'fight' the room stat - two stats trying to do the same job, but confusing eachother.

Thanks. Can you identify what kind of valves the radiator in my bathroom are? Are they manual valves? Or are they lockshield valves? You can see the photo from this comment https://forums.moneysavingexpert.com/discussion/comment/79940518/#Comment_79940518

I tried to remove the cap on the right side valve, the inside looks exactly the same as the left side valve. I don't know the purpose of each side, and don't know which one should/shouldn't be adjusted. 

To turn off the radiator in bathroom, which side should I adjust? I tried to turn the right side clockwise and I can hear the water flow seems reduced but not completely stopped.

Can I turn if half on?

ThisIsWeird

tristanjourney said:

Thanks. Can you identify what kind of valves the radiator in my bathroom are? Are they manual valves? Or are they lockshield valves? Yes - they are both. Identical. The differnce betwixt a manual valve and a lockshield is usually just that one has a knurled knob to make it easier to adjust - you use this to manually turn the heat output of the rad up and down - and the other has either a loose, smooth, decorative cap which doesn't turn the spindle underneath. This is the lockshield, and all rads should have one. It is set by the installer in order to 'balance' the system, so that each rad - whatever its size or location - gets the correct amount of flow, so isn't starved by other rads, or steal from others.

I tried to remove the cap on the right side valve, the inside looks exactly the same as the left side valve. I don't know the purpose of each side, and don't know which one should/shouldn't be adjusted.

To turn off the radiator in bathroom, which side should I adjust? I tried to turn the right side clockwise and I can hear the water flow seems reduced but not completely stopped.

Can I turn if half on?

BitinBOLD above first ^.

Usually, but not always, the lockshield is on the 'return' side of the rad. The 'return' is the water leaving the rad, so should be cooler. Can you compare them? Or, wait until it's cold, and then see which valve/pipe heats up first - that's the 'flow', so the manual valve (or TRV) should be there.

A note about adjusting lockshields. It's ok to do this, BUT you should first ascertain its position before any adjustment, so you can always return it to that same position if things go pear-shaped. An easy way is to tape a small paper flag to the spindle, and then count how many turns and part-turns it takes to fully close. Write that on the flag.

I suspect the knobless valve is the LS.

Is it ok to shut off that rad? No idea. It really depends on what by-passing it is doing.

Modern boilers have built-in by-passes, so it just ain't needed. And in any event, the rad in the room with the wall stat will always be 'open', so there's your CH by-pass if needed.

Old CH systems which used gravity-assisted hot water heating often needed a by-pass to prevent the whole caboodle boiling - but that's 'old'. 

There was a trend for putting the bathroom rads - especially towel rails - on the DHW circuit instead of the CH one, so that you'd always had dry towels even in summer time whenever you heated up your water tank and the CH was off. I suspect that's what you have here, but don't know.

Ok, we STILL don't know WHEN this rad heats up. Can you confirm, please? When this rad is 'hot', what else is on - the CH or the DHW?

tristanjourney

ThisIsWeird said:

Ok, we STILL don't know WHEN this rad heats up. Can you confirm, please? When this rad is 'hot', what else is on - the CH or the DHW?

Neither CH nor HW is on. That is what worries me...

There was a trend for putting the bathroom rads - especially towel rails - on the DHW circuit instead of the CH one, so that you'd always had dry towels even in summer time whenever you heated up your water tank and the CH was off. I suspect that's what you have here, but don't know.

Wouldn't that cause the bathroom too hot during summer?

BUFF

does your hot water cylinder have an immersion heater &, if so, is that on?

tristanjourney

BUFF said:

does your hot water cylinder have an immersion heater &, if so, is that on?

hmm, not sure, how can I find it out?

ThisIsWeird

tristanjourney said:

ThisIsWeird said:

Ok, we STILL don't know WHEN this rad heats up. Can you confirm, please? When this rad is 'hot', what else is on - the CH or the DHW?

Neither CH nor HW is on. That is what worries me...

There was a trend for putting the bathroom rads - especially towel rails - on the DHW circuit instead of the CH one, so that you'd always had dry towels even in summer time whenever you heated up your water tank and the CH was off. I suspect that's what you have here, but don't know.

Wouldn't that cause the bathroom too hot during summer?

Yes, but it's only a towel rail, and theoretically only on when the boiler is heating the hot cylinder, say an hour in the morn and a half hour later- ish. If folk use a lot of water, say for showers and baths, so the boiler is doing DHW more than this, then they'd likely appreciate warm dry towels then too :-)