Radiators hot at top,warm at bottom, Flow rate??

[npl2009]

Hi, first sorry about the length of this question.

I started of with a valiant boiler gravity fed system, this was installed by the pervious owners of my house. The boiler was located next my upstairs toilet, I wanted to move the boiler downstairs so I could build a shower room in its place. The plumber advised my that while I was moving the boiler I should change to Mega flow type system, he installed 210litre tank too. However, the radiators didn't heat up, he found a blocked valve and this partially fixed the issue, but the radiators never worked that well. He then said that the pipe work needed to be replaced to 22mm downstairs to make the system work correctly. At this point I decided to get a second opinion, the second plumber found that when the boiler had been moved the previous plumber had linked straight into 15mm pipes which restricted the flow around the house. So he advised that I run 22mm pipe back to the original boiler location and connect back to the pipe work there. At a cost of £900 I agreed for him to do this, after doing the work the radiators downstairs didn't heat up fully, and he said the the radiator were old and needed to replaced. So we replaced the 5 radiators, but the only get hot at the top and warm at the bottom, and this is with most of the radiators switched off upstairs. Now he thinks that the system might need a power flush, as the water was black when he drained the system.

Can anyone please advise what checks I can make to improve this situation?, I have reasonably large house and the radiator furthest away are causing the problem, the return pipes are only warm, does this mean I have a problem with flow, should I have replaced the pipe work as the original plumber suggest?

Any help would be greatly appreciated [/b]

 

[Fluffster]

Sorry to hear you have been having such issues which should have been put right by the plumbers you employed. The pipe work network could be the issue which is something that cannot be really commented upon from here as it has to be viewed in place.

If the previous plumbers have correctly balanced the system then it could be your pipe work design or possibly the pipework is restricted with magnetite deposits (oxidised iron debris from radiators)

A power flush maybe required and a magnetic filter Fernox TF1 for example would filter and trap this debris.

We generally carryout an inspection at no charge before recommending a power flush (if required).

Pete

 

[Blagard]

<snipped> I have reasonably large house and the radiator furthest away are causing the problem, the return pipes are only warm, does this mean I have a problem with flow

I'm not impressed by either plumber from what you have posted but I do wonder if you simply failed to accept recommendations and told them to do the minimum.

Warm return pipes mean you have circulation, but how much cooler than the flow is the real issue. You should try and measure the temperature of the flow and the return. The difference could easily be 20 degrees C and the system working fine.

Was the system flushed out with a cleaner prior to the pipework alterations the second time?

 

[npl2009]

Thanks for your comments, I had a go at balancing the radiators myself today, I now get all the radiators up to 50 degree at the top at least. The bottom half is 10 degrees less at 40 degrees. On most do the radiators I get a 30 degrees difference on the input versus the return. 67 degrees in and 37-40 degrees on the return pipe.

So in terms of heating my house this is a big improvement.

The quote I received to re-pipe my house was 6.5k, and involved lifting all the wooden floor at a cost of 1k, so I wanted to make sure this was completely necessary before do this work. So when the second plumber said I didn't think that was the issue I was understandably happy with what he was saying.

With regards to power flush, I was told that the system not been power flushed was the boiler was installed and when I asked the first plumber if I should get the system power flushed, he said it wouldn't make much difference and not to bother. He installed a magnaclean filter on my boiler to protect it.

I tempted to get a power flush done, to ensure my system clean, do you think this a good idea?

I'm planning on upgrading the pipe work upstairs and do the same down stairs when I have my new kitchen installed,

 

[Fluffster]

Like I said we always test the water and pipe work before recommending a power flush. Where are you based in London?

Pete

 

[npl2009]

I've move to Hertfordshire, rickmansworth. I've update my profile now