Increasing Pump Head

[corgiman]

Interesting theory DH complete nonsense but interesting.

And no it doesn't matter if the L/S is on the flow or the return, it is there to balance the system, and for isolation purposes.

And you say i talk rubbish. It is a lot easier to balance the rad if the trv is on the flow and the L/S is on the return. What I say is correct and i stand by that so get your geriatric mates to try to tell me I am wrong.

in the days of bi directional TRV's DIA is not talking rubbish and is totally right.

 

[wishiwascorgi]

so that means i am. WE could both be right but i also said that it is harder to balance if the L/S is on the flow and the trv is on the return

 

[doitall]

By closing the lock shield and opening it 360 it reduces the flow rate allowing the radiator to get hotter lower down the radiator. Depending on where the cold and hot meet depends on how much you turn the lock shield.

No you increase the flow to get the rad hotter

But it will get hot all over the surface area of the radiator and that was one of the questions that was asked.

No you increase the flow to do that

he has half hot and half cold on a new rad and all i told him was to close the lockshield or open to get the whole rad bouncing

No you open the L/S

And you say i talk rubbish. It is a lot easier to balance the rad if the trv is on the flow and the L/S is on the return. What I say is correct and i stand by that so get your geriatric mates to try to tell me I am wrong.

Don't make any difference on a two pipe system
Should mention with bi-directional valves which is obvious

So that means i am. WE could both be right but i also said that it is harder to balance if the L/S is on the flow and the trv is on the return

No it means you loose, it makes no difference
[/b][/i]

 

[D_Hailsham]

Interesting theory DH complete nonsense but interesting. If hot water enters the radiator it will rise to the top and displace the cold.

Yes, the hot water will migrate to the top, but it is not being pumped to the top, it rises because of the convection currents in the radiator.

As for my "nonsensical" theory, I was not thinking about the steady state where the radiator is full of water but the initial state when the system is being filled. If there was no restriction at the output, the water would just flow along the bottom of the radiator. The water has to be flowing into the rad faster than it can exit for the rad to actually fill with water.

And no it doesn't matter if the L/S is on the flow or the return, it is there to balance the system, and for isolation purposes.

So, opening the L/S valve will certainly give a higher flow rate but the effect will be that the radiator will not get so hot.

I can't imagine a concept so ill-conceived and fundamentally wrong.

The purpose of the L/S valve is to prevent the water leaving the radiator too quickly, not preventing it entering too quickly.

I stand corrected

So all the instructions about balancing radiators are wrong are they?

They all say that you close the L/S valve to increase the temperature drop between flow and return; and vice-versa. Now the only way there can be a difference in temp between flow and return is if the water has given up some of its heat. This heat must have gone somewhere, i.e. into the metal of the radiator. So if closing the L/S valve increases the temp difference, there must be more heat dissipated into the rad and the rad will get hotter.

 

[doitall]

Think about it D_H

You close the L/S to increase the temperature drop between the flow and return.

Less hot water in radiator means colder return.

Less flow of hot water through radiator means it takes longer to reach temperature.

Got it now

 

[D_Hailsham]

I found the cause of my low flow, I had a kinked pipe which I replaced and now it heats up fine.

So it was nothing to do with having the wrong pump, or the radiator being too high or the friction losses in vertical pipes etc etc.

The whole problem was caused by bad workmanship.

Now, what's that saying: Those who can do: those who can't (you can finish it)

 

[Balenza]

D Hailsham wrote

Sanj varah wrote
I found the cause of my low flow, I had a kinked pipe which I replaced and now it heats up fine.

Where has Sanj written this ?.

 

[Breesey]

Where has Sanj written this ?.

Halfway down page 3

 

[Balenza]

Crikey.

Five pages all over a kinked pipe.
It looks like sanj should stick to the theory.

 

[doitall]

Crikey.

Five pages all over a kinked pipe.
It looks like sanj should stick to the theory.

Most of it was whether you should close or open the L/S valves to increase the heat in the radiator

Your comments would make a few people happy or not

 

[Balenza]

Doitall wrote

Your comments would make a few people happy or not

Id fully open the lockshield and use the kinked pipe instead to throttle flow (cheaper) and use various degrees of kinkability to vary the flow to the rad in question with more kinkability (hence throttling) causing a greater temperature difference between flow and return.

 

[Agile]

I found the cause of my low flow, I had a kinked pipe which I replaced and now it heats up fine.

So all his theory and calculations did not identify the kinked pipe as an additional flow resistance.

That still does not explain his statement that a heating circulator will not work if the building has more than three floors!

Perhaps thats only when the pipe is kinky?

Tony

 

[doitall]

I found the cause of my low flow, I had a kinked pipe which I replaced and now it heats up fine.

So all his theory and calculations did not identify the kinked pipe as an additional flow resistance.

That still does not explain his statement that a heating circulator will not work if the building has more than three floors!

Perhaps thats only when the pipe is kinky?

Tony

Makes you wonder why they make bigger pumps dunit

 

[Softus]

Not really. Bigger pumps provide a greater flow rate (not velocity) and overcome greater circuit resistance.

That still does not explain his statement that a heating circulator will not work if the building has more than three floors!

It's because he is a theorist and without any practical nouse that would enable him to spot when a theory is flawed and/or ridiculous.

 

[doitall]

YA mean they shift more water