Radiators never get hot - help

[bigbohan]

I've no doubt that this question has been asked many time as conducting a search has resulted in a number of previous posts. None of them are exactly like my situtation so I was wondering if anyone can help.

In Nov (2009) we had a brand new Vaillant Eco Tec Pro 24 installed upstairs in the back bedroom, replacing where the old hot water storage system used to be. We thought that this would cure our heating problems as the boiler which we replaced packed in last year.

The problem is though that apparently we are on a one-pipe system and literally the only radiators that get hot are those located upstairs.

The one in the bathroom has been converted two-pipe system (so I've been told) and this does get extremely hot. The others in the bedrooms get hot enough to warm the room so I am not concerned about those.

The radiators downstairs are luke warm at best even after the heating has been operating for 4 hours! It seems that the further away you are from the boiler the cooler the radiator. Initial research on the Internet suggested that the pump may be the issue but surely a brand new boiler would not have this problem?

Is there nothing I can do to get more heat into the downstairs radiators? Even though the installed said it is symptomatic of a one-pipe system surely they must have worked in the past? We are sat here of an evening wrapped up in multiple layers of clothes under a spare duvet having paid over £1600 for a new boiler and fitting! What we do?

Many thanks in advance.

 

[glasgowgas]

have a look at balancing radiators in the FAQS for a starting point

 

[bigbohan]

I was told that balancing the radiators would not make a difference.

I cant remember whether I was told it was due to the fact that it was combi/condensing boiler or that it was due to it being a one-pipe system.

I'll take a look now though. Thanks.

 

[glasgowgas]

I was told that balancing the radiators would not make a difference.

whoever told you that is a cowboy

I cant remember whether I was told it was due to the fact that it was combi/condensing boiler

absolute b o llox

or that it was due to it being a one-pipe system.

all systems must be balanced especially one pipes

I'll take a look now though. Thanks.

try closing the bathroom lockshield right down to closed and see what difference it makes to other rads, post back, we will try and keep you right

 

[bigbohan]

OK. I'll give that a go to see if it makes any difference. Thank you for the suggestion.

 

[D_Hailsham]

Here is a drawing showing the difference between one-pipe and two-pipe systems.

View media item 17739
In one pipe systems the flow temperature slowly decreases as it gets mixed with the cooler water leaving each radiator. This means that, as you move down the chain, radiators have to be progressively oversized to account for the reduction in flow temperature.

If the position of the boiler in the chain is changed, e.g moved to the other end, the rad sizes will now be wrong.

But in a two pipe system, all radiators receive the same temperature water at their flow connection. So you do not have to oversize radiators and, speaking generally, the location of the boiler in the system is irrelevant.

Could moving the boiler have messed up your system?

 

[bigbohan]

It's difficult to say whether moving the boiler has made a difference as the previous boiler was a heap of junk. I think they built the house around the bolier and the house was built in the 1930's!

We never really got much heat out of the old boiler but we put that down to its age and inefficiency.