new boiler, rads are cold at bottom and 1 doesnt work

[angela1982]

This is the link to the WIKI. It gives you an idea of what is involved to do it all "accurately" which requires proper equipment, but also an overview of the order in which to do them which is helpful at this stage.

Than you cantaloup63, thats a very comprehensive step by step guide. Think i'll be calling my plumber up and tell him to get his bum back here to balance them correctly as I'm now certain that is the problem. the rads which were causing me issue had the lockshield valves open about 5 or 6 turns!! no wonder they werent working properly

Thanks once again

 

[cantaloup63]

You may well be able to get it going by ignoring the measurement stuff and just following the rest of the routine - the key is working out the order in which the rads get heated up, which is of course a problem if some of them don't get warm at all!!

 

[angela1982]

I've started the balancing but have reached rad number 8 and it won't heat up at all, both pipes are cold! Im turning the LS valve 1/8 at a time but nothing is happening! What am i to do now! We tested it independently yesterday and it heats up when all others are switched off. What could be the problem? Ps this is a new radiator in the extension.

 

[Youllneverguess]

If it works as the only rad on the system, you will need to close the others down a little more. Opening the LS up past a certain point offers you no benefits.

 

[angela1982]

OK thanks, dont quite get your last comment but thanks anyway.
If the other rads before it were closed anymore they'd be half cold as they weren't even open more than 1/4 or 1/2 a turn each.
Think its time to call the plumber back.
Thanks

 

[Youllneverguess]

Microbore refers to the size of the pipework and not the boiler. Microbore is roughly the same width as your little finger and 15mm is that of your thumb.

Blimey you have small hands.

 

[monoxide62]

Microbore is roughly the same width as your little finger and 15mm is that of your thumb

22mm is my little finger , 28mm is my thumb with 54mm being my....................

 

[sooey]

lengthwise???

 

[cantaloup63]

Microbore refers to the size of the pipework and not the boiler. Microbore is roughly the same width as your little finger and 15mm is that of your thumb.

Blimey you have small hands.

I was sort of thinking that the op, being female, might have more delicate hands than you bunch of orangutans

 

[Youllneverguess]

I'm not even going to start down that route

 

[angela1982]

I'm not even going to start down that route

right, now that you guys have sorted who's got the biggest! can you please help me!

I re-started the balancing. To clarify how i do it is starting will all lockshields off, TRV's on full. I go in order of the rads closest to the boiler, turning the LS valve 1/8 turn at a time,even less sometimes, until both the inlet and outlet pipe are the same temp. When i get to rad number 7 (which is the first one from the new extension) that doesnt heat up. So i turn all previous rads down a touch at a time, the 7th rad starts to heat up, but not fully, only luke warm. If i turn down the previous rads any further they go cold. Any suggestions please??
This is getting really frustrating as I feel like i'm getting somewhere but whenever i get to the same point it all f.....s up!
p.s. that rad heats up when all others are off, but it doesnt do until the LS valve is open 1.5 turns! could that be the issue, perhaps a faulty LS valve?

 

[MANDATE]

The fact that you have not got very far, suggests to me the root cause of the problem is elsewhere.
Yes! it is essential, radiators need to be balanced so each radiator gets sufficient flow to give the desired temperature for the room.
The problem radiator works ok when others are off, but not when others are on.
This is caused by too much resistance in the pipe work.
Usually there is a by pass valve which allows water to go from the 'flow' to boiler 'return'. Now if this valve is open too much, the water will take the easier path and go back to boiler rather than go to the problem radiator.
The radiators subject to this type of problem are those furthest away from pump.
Also if the heating system is divided into two sections all the lockshields on one section may have to be opened/closed a little for the other section to perform.

The flow through the radiator is dependent on water being pushed against what ever resistance exists. Which brings me to another important issue, the pump.
A friend had a similar problem, radiator did not heat up. Radiator removed, cleaned and replaced. made no difference(yet other radiator in same room hot).
Finally located by pass valve and closed it down and radiator got warm but not hot.
Next removed pump for examination, black scale formed around inlet and outlet. 20mm orifaces down to about 7mm so pump could not push water to problem radiator.
Decision made to replace pump and isolating valves.
New pump fitted, readjust by pass and rebalance problem radiator, no further problems

 

[angela1982]

The fact that you have not got very far, suggests to me the root cause of the problem is elsewhere.
Yes! it is essential, radiators need to be balanced so each radiator gets sufficient flow to give the desired temperature for the room.
The problem radiator works ok when others are off, but not when others are on.
This is caused by too much resistance in the pipe work.
Usually there is a by pass valve which allows water to go from the 'flow' to boiler 'return'. Now if this valve is open too much, the water will take the easier path and go back to boiler rather than go to the problem radiator.
The radiators subject to this type of problem are those furthest away from pump.
Also if the heating system is divided into two sections all the lockshields on one section may have to be opened/closed a little for the other section to perform.

The flow through the radiator is dependent on water being pushed against what ever resistance exists. Which brings me to another important issue, the pump.
A friend had a similar problem, radiator did not heat up. Radiator removed, cleaned and replaced. made no difference(yet other radiator in same room hot).
Finally located by pass valve and closed it down and radiator got warm but not hot.
Next removed pump for examination, black scale formed around inlet and outlet. 20mm orifaces down to about 7mm so pump could not push water to problem radiator.
Decision made to replace pump and isolating valves.
New pump fitted, readjust by pass and rebalance problem radiator, no further problems

Hi Mandate,
The boiler is only 2 years old and was serviced by the manufacturer in December last year but the problems were there before and still after the service so i think i can rule out a faulty pump. I might see if the pump speed can be turned up, i looked in the manual but couldnt find anything of how to do that.
My plumber said he wasnt happy with some of the pipework the old plumber did, too many bends and unecessary bends, he thinks thats the problem but of course i dont want to be paying to have my floorboards pulled up without eliminating pretty much everything else it could be! Does that sound feasible to you, that if there were too many bends in the pipework this would cause the rads to not heat properly. Rads 1-6 heat up fine, LS valve only open 1/4 turn. Rad 7 doesnt heat up, Rad 8 heats up fully with LS valve open 1/2 turn, Rad 9 doesnt heat up and Rad 10 heats up hot at top, cool at bottom with LS valve open 1.5 turns and rad 11 gets mildly warm at top but cold at bottom

 

[Terry7556]

hi angela you cannot assume that because you had a service last decmber
that your pump is ok. i would be surprised if your pump was even glanced at, never mind touched or checked (unless you saw something different happen).the FAQs have have some info on checking pumps, and you can adjust the speed by turning a switch on the side marked 1-2-3, if your pump has such a switch, some dont

 

[MANDATE]

As I see it there are a few situations to consider.
Pump! ok pump is working, but is it restricted in any way around the inlet and outlet orifaces or are the isolating valves either side of pump partially closed.
The flow to a radiator is caused by pump pressure overcoming resistance in pipe work. If pump pressure goes down or resistance goes up the flow is adversely affected
Agree adding extra pipe work and fitting elbows and bends all increase the resistance little by little. Likewise scale or partial blockages will increase resistance in due course, while the pump becomes less effective resulting in a struggle to supply every radiator.
A wrongly adjusted by pass valve gives the water a easier escape route and this should be checked out first.
Dont know if you have radiators in correct order, but if 6 and 8 heat up and 7 does not, then must suggest blockage/valve problem at the inlet/outlet of 7.
Also the fact 10 does get hot (only at top) whilst 9 remains cold suggests its the same problem as 7
I would have thought the order would be 'fully working' followed by 'partially working radiators' followed by 'cold non working radiators'
Out of interest are all 11 radiators on one circuit, or is there two circuits with one circuit having all the problem radiators.