zoothorn

Extension- Last Stuff.

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20 minutes ago, PeterStarck said:

I've already asked and was told no.

What about one of these, probe clipped to radiator, cheap as chips?

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12 minutes ago, joe90 said:

What about one of these, probe clipped to radiator, cheap as chips?

 

They are excellent, invisible too. 

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2 hours ago, PeterStarck said:

 

So is the radiator in that bedroom consistantly the same temperature as the other radiators and it is the room temperature which varies.

 

The rads all do the same it seems, not pumping out heat until suddenly 8am ish. Most times. Sometimes they start earlier consistant with a normal 7 ish am time (why this big inconsistancy, when the outside sensor's job is to regulate & produce a similar heat inside, if irregular heat outside.. is a Q Id surmise only for Vaillant).

 

But I can only tell if new top room isn't warm at 8am one day, better the next, etc.. because you see most of the other rooms you cannot tell any difference the rads being on for hours bc room temp increaces by only 1 or 2* all day! (maybe 3* in main room if lucky).

 

In new rooms, the temp does at least increace by enough -only just in top room tho- to feel a scrap of warmth AM sometimes, average warmth at its very best effort sometimes say 5pm. I can only determine the 'health' of the CH by measuring in the new room.

 

 

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Ok they will get warmer on the circuit but to be honest you’ll need to switch it all on when the rads are cold and then start walking round and see which rad gets warm first just by feeling the joint where the pipe valve joins the rad. 
 

From this you start to balance the rads by turning all the lockshields off. Closest gets a half then open, next gets one turn and so on. You can also frig the balancing to give the more “needy” rooms more heat by opening them more than the ones needing less heat but it takes time and patience. 

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@PeterW understood. But this exercise is nigh on impossible.. because of the 'delay' of when they actually suddenly give out heat, you just dont know when this point will be day to day even a series of similarly cold days one day 7.40am, next day 8.15am, another day 6.55am.

 

Once I get the noise stopped (if ever do) & determine why inconsistancy in 8am room temp day to day, & get this evened out.. I can fine tune it. But this looks like a long way away: Vaillant I get impression have no idea (just like overnight noise- no idea). In meantime I'm happy enough with the balance, I think, even if not perfect.

 

Thanks.

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But the rooms aren’t heating up so how can you be “happy enough with the balance”..??! Balancing will sort some of these issues. 

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3 minutes ago, PeterW said:

But the rooms aren’t heating up so how can you be “happy enough with the balance”..??! Balancing will sort some of these issues. 

 

The rooms aren't heating up, because they're too cold to do so. Its not the fault of the CH system (once it's decided to actually come on 90mins after I told it to). It has no possible chance of getting my bathroom above 13.3*C on a cold day, with the rad on hot most of the day. And if the rad's on at the same time and temp as the others, them afaict it is sufficiently balanced, if not pin-point perfectly, so Im happy with this aspect: in fact its the only thing thast seems to be correct!

 

Imagine plonking a small rad in a single brick small 2mx2mx 2.5m H contruction, snow outside, on clay, tin roof on (the best idea of how my bathroom feels) it wouldn't heat the room, the heat would just go up above the rad & disaapear. Sit on a khazi 1m away from rad & you'd barely notice it was on.

 

If adjacent to it there was another the same, but with insulation, under floor too, on roof.. it'd get the room warm. But the two identical rads aren't unbalanced just bc you measure very different temps in the two rooms tho. You wouldn't curse the CH in the 1st room.. you'd only curse the room.

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How hot are the radiators actually getting? 

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Or the rooms aren’t heating up because the radiators aren’t balanced, system isn’t full of water, the system is full of air, the radiators are undersized for the rooms.

 

its a process of elimination 

 

 

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2 minutes ago, MJNewton said:

How hot are the radiators actually getting? 

 

Well I can only say 'to what Ive set them to go to' 55*. So actually 5* above usual for this system I believe.

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Just now, TonyT said:

Or the rooms aren’t heating up because the radiators aren’t balanced, system isn’t full of water, the system is full of air, the radiators are undersized for the rooms.

 

its a process of elimination 

 

 

 

Yes, but if one room -does- get toasty unlike the remaining cold ones, and all the rads are equally as hot and equally as on timewise.. then they're not unbalanced, its just the rooms that are "unbalanced". You can't expect a rad to 'know' the characteristics of the room & change its performance accordingly, unless of course it has a trv (none of mine do).

 

I'd think you could say purely by the rads coming on similar timewise, and similar heat, that they are sufficiently balanced. There's nothing suggesting a radiator imbalance, I'm rather bewildered by the suggestion tbh.

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12 minutes ago, zoothorn said:

 

Yes, but if one room -does- get toasty unlike the remaining cold ones, and all the rads are equally as hot and equally as on timewise.. then they're not unbalanced, its just the rooms that are "unbalanced". You can't expect a rad to 'know' the characteristics of the room & change its performance accordingly, unless of course it has a trv (none of mine do).

What you're saying when you say "it's just the rooms that are unbalanced" means the radiator is too small for the room.

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25 minutes ago, zoothorn said:

 

Well I can only say 'to what Ive set them to go to' 55*. So actually 5* above usual for this system I believe.

 

Not quite sure what you mean by that? Seems a long way of saying 55C? To avoid misunderstanding, you are measuring this? (ie it's not just what you've set it to) 

 

I don't have any experience of those sorts of temperatures, but it does sound low to me and I'd expect a major contributor to why the rooms aren't heating up? 

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13 minutes ago, zoothorn said:

I'd think you could say purely by the rads coming on similar timewise, and similar heat, that they are sufficiently balanced. There's nothing suggesting a radiator imbalance, I'm rather bewildered by the suggestion tbh.


You don’t understand rad balancing.
 

What you need to understand is that you need to reduce the flow - heat input - into certain rooms and increase it in others. That allows you to ensure that the rooms that need more heat get a better flow, and heat is “lost” to the room quicker increasing room temperature. 
 

For example, your workshop I would turn right down, whilst bathroom and bedroom sound like they need to be more open. 
 

Also, if the rad isn’t heating the room (such as the bathroom) then it’s too small. Rads have BTU or kW outputs, if the the rad is too small you will not get enough heat from it.  

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3 minutes ago, MJNewton said:

I don't have any experience of those sorts of temperatures, but it does sound low to me and I'd expect a major contributor to why the rooms aren't heating up? 


It’s a heat pump so won’t be as hot as the temperatures you see for a boiler

 

6 minutes ago, PeterStarck said:

What you're saying when you say "it's just the rooms that are unbalanced" means the radiator is too small for the room.

 

Yep agree - and the rads need to be sized for the lower room / flow delta temperature 

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2 minutes ago, PeterW said:


It’s a heat pump so won’t be as hot as the temperatures you see for a boiler

 

Absolutely, and my main concern was that the actual radiator temperature (average across flow and return) might be even less than 55C as it is not clear how/where its being measured. 

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11 minutes ago, PeterStarck said:
11 minutes ago, PeterStarck said:

What you're saying when you say "it's just the rooms that are unbalanced" means the radiator is too small for the room.

 

No, Im defo saying the room's too cold for the rad! they physically cannot be bigger in: kitchen, bathroom, bedroom, spare bedroom, both the main room's rads cannot be any bigger too. New bedroom I think has the biggest rad in wales in tbh.

 

The only room possible to get a bigger rad in, bc I asked them not to put in a medium they wanted to (bc I had the intuition it'd be too hot in there.. & I was right) was the toastiest room, the new workshop, with its small rad in.

 

Its impossible to explain this house I think, both the layout, the 4x different builds cobbled together, especially the huge difference in insulative aspects one room to the next. Almost as impossible as coming down 2p with your thermometre reading 9*C Peter! It'll be spring soon & my plums can come down again.

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15 minutes ago, MJNewton said:

 

Absolutely, and my main concern was that the actual radiator temperature (average across flow and return) might be even less than 55C as it is not clear how/where its being measured. 

 

It's not.

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I still think upstairs rad is plumbed into the return of the system.

Can't remember what my basis is on this.

 

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17 minutes ago, PeterW said:


It’s a heat pump so won’t be as hot as the temperatures you see for a boiler

 

 

Yep agree - and the rads need to be sized for the lower room / flow delta temperature 

 

 

Unless the system enables you to put it up to 55* though: mine feel 'very hot' ish, much like a typical boiler rad.. if not super hot these sometimes run at like maybe 58 or even 60 (?). A very good temp I was thinking today 5pm, ass on rad, but go 1m away & you'd not know it was even on.

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2 minutes ago, dpmiller said:

 

It's not.

 

 

No this is true, my 55* is solely based upon what me (& Vaillant chap on phone telling me how) set the flow temp to on the digi controller, upped it from 50*.

 

I'm happy all rads are hot enough, and working one to the next consistantly whether 53* or 57*. That is all I am confident in tho.

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If that was your bare ass on the radiator I don't reckon it is 55C. You really need to measure them Zoot - it could really help pinpoint where the problem lies. 

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1 hour ago, zoothorn said:

No, Im defo saying the room's too cold for the rad! they physically cannot be bigger in: kitchen, bathroom, bedroom, spare bedroom, both the main room's rads cannot be any bigger too. New bedroom I think has the biggest rad in wales in tbh.


Seriously, a number of us are trying to help and at every turn you say we are wrong. 
 

Unless you’ve got a floor to ceiling rad in the bathroom then you don’t have rads that are maxed out. Trust me, I’ve fitted some huge rads in my time and you’ve seen nothing ..!

 

1 hour ago, zoothorn said:

much like a typical boiler rad


Standard boiler run temp is 65-72°C 

 

These will be “standard” rads but when you size them you change the flow temps. I’ll give you an example. 

Using BS EN 442, the industry standard for radiator sizing, a delta 50°C is assumed for calculation. This delta is the difference between the average flow temperature and the desired room temperature. Most plumbers / Heating engineers therefore use a flow temp of 70°C and a target room temperature of 20°C. 
 

My “room” example is a 3.5 x 3.5m living room with a standard ceiling of 2.4m. I’ve said it has two 9” solid external walls, and no insulation under the floor. I’ve added a single 1sqm window that is double glazed. 
 

The heat requirement of this room is 1540 W based on delta 50°C. To heat this room, I would specify a 1100 x 450 double convector compact radiator. 
 

If I now change the delta to delta 35°C, then the room loss is still the same but the rad now needs to be an 1800 x 450 double convector compact radiator. 


Do you see the difference ..?? 


The radiator for the lower flow temperature is 63% larger to accommodate the same heat requirement. 
 

I can - from your numbers and description - see that your bathroom should have something like an Opus 600 towel rail, which is 600 x 2000..!! If you’ve got anything smaller, it is undersized. It’s not the room, it’s the rads. 

Edited by PeterW
Corrected as below
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15 minutes ago, PeterW said:

Using BS EN 442, the industry standard for radiator sizing, a delta 50°C is assumed for calculation. This delta is the difference between the flow temperature and the desired room temperature

 

It's not even that - it's the difference between the *average* radiator temperature (thus (flow-return)/2) and room temperature which therefore drops the actual output even further. It doesn't change the rest of your point though so don't anyone let my pedantry get in the way! 

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