I am struggling to get a couple radiators to work. What could be the problem?

JadeHighland

WIAWSNB said:

JadeHighland said:

Is there such thing as a TRV valve without a dial? That second valve doesn't twist off like the other. It turns and stops like a TRV. I'll report back on the turns tomorrow. 

There are essentially two types of radiator valve - a TRV, and a 'manual'. 

The TRV, as you have found, has a spring-loaded 'pin' that sticks out, and when you press it firmly down it shuts the valve off. When you release it, it pops back up. The 'head' controls this by pressing down the right amount depending on the room temp.

Then there's the 'manual' valve. This has a 'spindle' which you turn, just like a tap. Turn it clockwise and it shuts the rad off, anti and it opens. It'll have a good 5-ish turns within that range.

If you fit a cap - a knob - on that spindle that engages with the spindle so it turns it, like the white one on the white rad looks to be, but might not, then it becomes a 'control' valve, which is one you'd usually adjust in order to control the amount of heat coming out that rad - its on and offability. Obviously, tho', if the other end has a TRV, you let that do the controlling instead, and you don't normally touch the other end.

Ok, if you pull off that 'control' knob and replace it with a 'cap' that doesn't engage with the spindle but just spins loosely ad infinitum, then that valve is now a 'lockshield' type. 

The idea is that each radiator in your circuit gets the right amount of flow for it to work equally - balanced - with the other rads. So, a larger rad's lockshield would be opened slightly more. A radiator at the end of the pipe run would ditto. Once the lockshield spindles are tweaked the right amount - 'balancing' your system - then the protective cap is pushed on and you don't touch it again. So, lockshield valves usually have that loose cap that doesn't turn the spindle - you need to remove it to gain access to the spindle each time.

The other - non TRV - valve on your white rad appears to have a 'control' cap, but it should still be considered a 'lockshield'. So, once it's set correctly you don't touch that end - the TRV does all the controlling.

I asked that you count how far open each valve is so that we can determine the current 'lockshield' positions, and also hopefully shed light on the cause of the lukewarm rads.

So, you mark the position - starting point - of each spindle. You then turn it clockwise until the valve stops - it's fully off. You note down how many turns and/or part-turns that takes. It could be a fraction of one turn, or a few turns.

If you could do that for the white valve, and then both towel rad valves, please. 

If any of these caps/knobs just spin loosely and are clearly not attached to the spindle, then pull them off first.

Please report back.  

Heya. White radiator turns a good 5 times before stopping. I have to use a flat head for the towel one but it's the same. 

Slinky said:

Have you tried turning off every other radiator in the house and seeing what happens? Do they get hot then?

We extended our house and had problems with the lounge taking a long time to warm up. Upstairs, where the boiler is and had all new piping, was nice and hot, downstairs where we had the original 1960s pipes plus new piping in the extended parts wasn't. Got around the problem by having a faster pump. Not much other option than digging up the floors to replace the pipework which we didn't want to do.

We have one in the hallway that was struggling (downstairs next to the living room one). Turned off all the heaters upstairs, ran it for a bit and it started getting pretty warm after. Apparently I was forcing some air out in the system. 

For whatever reason, I can't get the same result with the two newly fitted ones. Each time I try balancing, forcing air out, turning of upstairs or downstairs, the most I've got is it gets mildly warm. 

WIAWSNB

JadeHighland said:

Heya. White radiator turns a good 5 times before stopping. I have to use a flat head for the towel one but it's the same. 

We have one in the hallway that was struggling (downstairs next to the living room one). Turned off all the heaters upstairs, ran it for a bit and it started getting pretty warm after. Apparently I was forcing some air out in the system. 

For whatever reason, I can't get the same result with the two newly fitted ones. Each time I try balancing, forcing air out, turning of upstairs or downstairs, the most I've got is it gets mildly warm. 

Thanks. Ok, that's disappointing. 

I was hoping you'd find the white lockshield only required a part-turn before being fully off, as this would have suggested it simply needed opening a bit more to allow a greater flow. But, at 5 turns open, it's pretty much fully open. So, if the white lockshield is 5 turns open, and the TRV pin is fully up, then that rad is getting as much flow as it can, assuming the other house rads are still not pinching most of it. However, by shutting off the other house rads, the white one should heat up fully and quickly. But it doesn't.

That suggests summat else is amiss. It could be plumbing fault - the pipes were run to it incorrectly. Or it could be a partial pipe blockage. Or I guess the valves could be faulty - stuck partially closed inside - but that's very unlikely. 

By the way, by making a rad become hot by shutting off other rads isn't usually a result of shifting air out of the system, but simply 'rebalancing' it - ie, by depriving other rads of flow, the cool rad now gets more. 

The black towel rad is the same - if both ends are opened by a few turns as you say, then that rad is fully open. 

Oookaay, have you tried bleeding these rads? If not, please do so, and report back - any hiss, and for how long?

And do you have a magnetic filter fitted near your boiler? If so, do you know how to check and clean it?

And, does your boiler have a pressure gauge? 

JadeHighland

WIAWSNB said:

JadeHighland said:

Heya. White radiator turns a good 5 times before stopping. I have to use a flat head for the towel one but it's the same. 

We have one in the hallway that was struggling (downstairs next to the living room one). Turned off all the heaters upstairs, ran it for a bit and it started getting pretty warm after. Apparently I was forcing some air out in the system. 

For whatever reason, I can't get the same result with the two newly fitted ones. Each time I try balancing, forcing air out, turning of upstairs or downstairs, the most I've got is it gets mildly warm. 

Thanks. Ok, that's disappointing. 

I was hoping you'd find the white lockshield only required a part-turn before being fully off, as this would have suggested it simply needed opening a bit more to allow a greater flow. But, at 5 turns open, it's pretty much fully open. So, if the white lockshield is 5 turns open, and the TRV pin is fully up, then that rad is getting as much flow as it can, assuming the other house rads are still not pinching most of it. However, by shutting off the other house rads, the white one should heat up fully and quickly. But it doesn't.

That suggests summat else is amiss. It could be plumbing fault - the pipes were run to it incorrectly. Or it could be a partial pipe blockage. Or I guess the valves could be faulty - stuck partially closed inside - but that's very unlikely. 

By the way, by making a rad become hot by shutting off other rads isn't usually a result of shifting air out of the system, but simply 'rebalancing' it - ie, by depriving other rads of flow, the cool rad now gets more. 

The black towel rad is the same - if both ends are opened by a few turns as you say, then that rad is fully open. 

Oookaay, have you tried bleeding these rads? If not, please do so, and report back - any hiss, and for how long?

And do you have a magnetic filter fitted near your boiler? If so, do you know how to check and clean it?

And, does your boiler have a pressure gauge? 

Bled the radiators. No hissing, just water. Don't know what a magnetic filter is and boiler is properly pressurised. I think I might get it flushed and see if that changes anything. 

gefnew

You could try and increase the pump speed to force it through the system if not already set to max.

WIAWSNB

JadeHighland said:

Bled the radiators. No hissing, just water. Don't know what a magnetic filter is and boiler is properly pressurised. I think I might get it flushed and see if that changes anything. 

Ok, it ain't 'air'. And, being a pressurised system, it was unlikely to have been an air 'lock' either.

The filter is a usually-black cylinder around 8"-odd inches tall, mounted on the CH return pipe, usually close to the boiler - any such beast?

When you bled the rad, what colour was the water? 

Yup, we are at the getting-the-pros-in stage. Do you have a trusted plumber? 

Hang on - these are new rads, and never worked properly? Hmm, you know what you need to do, don'tcha? 

Albermarle

OP,
There was a similar thread recently and they actually found the problem. Just maybe it could be the reason for your issues.
Radiator issue — MoneySavingExpert Forum

WIAWSNB

Albermarle said:

OP,
There was a similar thread recently and they actually found the problem. Just maybe it could be the reason for your issues.
Radiator issue — MoneySavingExpert Forum

Now, that would be hilarious! Three plumbers getting their arris pipe mixed up with their elbow. Lawdie...

JadeHighland

gefnew said:

You could try and increase the pump speed to force it through the system if not already set to max.

Interesting. How would one do that? 

So, a bit of an update for everyone. Pressure gauge has always been at 1.5 bars when the heating wasn't on. When the heating was on, I noticed it was still around 1.5 bars and expected it to be higher. I topped up the boiler just a bit. Eye balling it, I changed it from 1.4 bars to about 1.6. Didn't think much of it, walked into the bathroom and for the first time the towel radiator was actually warm enough to heat the room. 

Heating has just turned on so will see if it's had any impact on the downstairs one. 

WIAWSNB

JadeHighland said:

gefnew said:

You could try and increase the pump speed to force it through the system if not already set to max.

Interesting. How would one do that? 
So, a bit of an update for everyone. Pressure gauge has always been at 1.5 bars when the heating wasn't on. When the heating was on, I noticed it was still around 1.5 bars and expected it to be higher. I topped up the boiler just a bit. Eye balling it, I changed it from 1.4 bars to about 1.6. Didn't think much of it, walked into the bathroom and for the first time the towel radiator was actually warm enough to heat the room. 
Heating has just turned on so will see if it's had any impact on the downstairs one. 

I suspect the pump is integral to the boiler? If so, then it's likely controlled by the boiler, so is unlikely to have a user-adjustable speed control on it. A GasSafe could possibly do this by tweaking the PCB controls, but it would have to be a reasoned decision.

Could you confirm make and model of boiler, please?

A pressure of 1.5bar is fine, and is actually a wee bit higher than I would normally suggest (in essence, the lower for the system stress the better), but it's perfectly ok. The pressure ideally shouldn't rise significantly when hot as boilers have Expansion Vessels inside them to prevent this from happening. However, it is quite normally for some pressure rise to occur. I'd suggest the fact that yours doesn't rise is 'good'. 

So, how did tweaking your system pressure seemingly cause this difference? No idea - it doesn't make much sense.

The only time I'm aware of when a higher-than-normal pressure may be required in a sealed system is in a multi-story home, where the boiler is on the ground floor, and there may be, ooh, 3 floors above it. If the ground floor gauge was set to 1bar, then the pressure on the top floor may well be less than satisfactory for good performance.

This doesn't appear to be the situation here, tho'? 

So, if increasing the pressure that small amount made a significant difference to performance, I'm stumped.

JadeHighland

WIAWSNB said:

JadeHighland said:

gefnew said:

You could try and increase the pump speed to force it through the system if not already set to max.

Interesting. How would one do that? 
So, a bit of an update for everyone. Pressure gauge has always been at 1.5 bars when the heating wasn't on. When the heating was on, I noticed it was still around 1.5 bars and expected it to be higher. I topped up the boiler just a bit. Eye balling it, I changed it from 1.4 bars to about 1.6. Didn't think much of it, walked into the bathroom and for the first time the towel radiator was actually warm enough to heat the room. 
Heating has just turned on so will see if it's had any impact on the downstairs one. 

I suspect the pump is integral to the boiler? If so, then it's likely controlled by the boiler, so is unlikely to have a user-adjustable speed control on it. A GasSafe could possibly do this by tweaking the PCB controls, but it would have to be a reasoned decision.

Could you confirm make and model of boiler, please?

A pressure of 1.5bar is fine, and is actually a wee bit higher than I would normally suggest (in essence, the lower for the system stress the better), but it's perfectly ok. The pressure ideally shouldn't rise significantly when hot as boilers have Expansion Vessels inside them to prevent this from happening. However, it is quite normally for some pressure rise to occur. I'd suggest the fact that yours doesn't rise is 'good'. 

So, how did tweaking your system pressure seemingly cause this difference? No idea - it doesn't make much sense.

The only time I'm aware of when a higher-than-normal pressure may be required in a sealed system is in a multi-story home, where the boiler is on the ground floor, and there may be, ooh, 3 floors above it. If the ground floor gauge was set to 1bar, then the pressure on the top floor may well be less than satisfactory for good performance.

This doesn't appear to be the situation here, tho'? 

So, if increasing the pressure that small amount made a significant difference to performance, I'm stumped.

It's a Baxi and model is a 825 I think.

The bathroom one is getting warm but downstairs still cold. I give up to be honest and going to get a plumber to flush the system or take a look when I can afford it.