Unsuccessful work done to cure cold rads

BigColy · 20 Mar 2008

Powermax 155 system. House is 8 years old.

It started last xmas with two cold downstairs rads - rest were hot. Rads removed and flushed and refitted with new valves. No success.

Have had the pumps and boiler checked out - all ok.

Local Plumbing company put cleaner in two weeks ago and performed power flush last Monday. No success. Indeed, I now have five cold rads!!!

The company now want to come in and rip up floor boards to try to locate the blockage.

Is this the normal way to go?

Bahco · 20 Mar 2008

Is it a microbore system perhaps?

Read post 8 FAQs and see if the tips help you.

The blockage will have to be sorted but strange after only 8 years.

BigColy · 20 Mar 2008

Bahco,

Wow! I cant believe how quick I got a reply .... thanks!
I read the FAQs as advised and, although these are very good, don't seem to help.

I really just want to make sure that I'm not being led down the garden path re pulling up floorboards to trace the blockage. I.E. is there any other treatment that would normally be tried first?

Again - thanks for the advice and quick reply.

ChrisR · 20 Mar 2008

First has to be the pump. They can be going slow, have the impeller undone or blocked.

9/10 times people who say they've "checked" a pump have done nothing of the sort.
You HAVE to take the pump apart, try to stop it (knowing what to look for), check it's clear, and check the valves. I used to check them with a tachometer as well, until I lost the second one...

having_a_gas · 20 Mar 2008

ChrisR said:
First has to be the pump. They can be going slow, have the impeller undone or blocked.

9/10 times people who say they've "checked" a pump have done nothing of the sort.
You HAVE to take the pump apart, try to stop it (knowing what to look for), check it's clear, and check the valves. I used to check them with a tachometer as well, until I lost the second one...

ChrisR
I'm interested in the tachometer you use to check pumps with as I have never seen one, where do you get these from? how do you use it?

Thanks

I would also add to the OP to turn off all the other rads and open each one that is not working one at a time to prove if its blocked or air locked. Problem may just be a bit of air and / or system needs balancing.

JPC · 20 Mar 2008

is at microbore ?

martyc · 20 Mar 2008

Sounds like pump/circulation..did u try turning up the speed of the pump??
Also turn off all rads except the ones that arent heating and see if they heat as said by someone else above
Marty

BigColy · 27 Mar 2008

Thanks for all the replies. To clarify :-

The system is 10mm microbore.
First thing I tried was closing all radiators off except the cold ones, each in turn. Also tried this again after the Power Flush.
The pump was certified 'ok' by a Heat Team engineer who was confident it was fine. He also turned it up to full speed.
Following the cleaning agent and Power Flush, I now have FIVE cold rads!

The local Plumbing Co. who performed the clean and Power Flush, say the house builders could have nipped a pipe with a clip or something, which has caused a block to get worse, hence they now want to pull up the floor boards up stairs and trace the pipes.
The chap also said this is the first time his Power Flush service has failed -despite 6 bottles of cleaner being put in.

Bahco · 27 Mar 2008

Hope you get it sorted.

********** Microbore!

fitz1 · 28 Mar 2008

take the pump outand check the flow side of it.had a similar problem on a job before xmas , and the flow side bore was vastly reduced with rock hardened sludge.

Agile · 28 Mar 2008

BigColy said:
The pump was certified 'ok' by a Heat Team engineer who was confident it was fine. He also turned it up to full speed.

He cannot certify it as fine unless he has removed the head to check for blockages.

If you now find its blocked then will the Heat Team engineer pay the costs arising from his missdiagnosis???

Do you even know his full name?

Tony Glazier

namsag · 28 Mar 2008

Wrong Agile if heat team have a similar lap top programme such as BG limpet system this will tell him exactly what the pump is doing and wether there is a blockage within it or impellor etc has come off. Which is all done in position.

Sounds like a pile of carp in manifolds and cutting out is best way to clear it

BigColy · 1 Apr 2008

fitz1 said:
take the pump outand check the flow side of it.had a similar problem on a job before xmas , and the flow side bore was vastly reduced with rock hardened sludge.

Wouldn't such a problem affect all rads? Some of them are piping hot.

superdupergasman · 1 Apr 2008

You can get a bit of crap partially blocking some rads in the manifold.

Water will find the easiest way to circulate and only use that path.

As the guys are doing, cut out manifold and check or replace. This would have been better done before flush. Powerflush never removes hard blockages and the source of the problem is better to be removed.

Only other solution that could work is cold main pressure down the pipes, or a foot pump on the pipework and blast in through.

BigColy · 4 Aug 2008

It has taken some time, but between the local plumbing company and myself we tracked down several blockages in the pipework to the cold rads. Solid blockages! And lots of rubbish (grit, scale, rust) in the system.
I think the problem must have stemmed from our first years in the house (eight years old now) when I had to top up the water in the Powermax 155 every week or so to maintain pressure. Couldn't find a leak, but eventually had the expansion vessel replaced which seemed to stop the need to top up. However, I recon I've inadvertantly watered down the inhibitor which has led to the problems.

Got a cleaner circulating at the moment. How much inhibitor should I put in once I clear and refill the system?

diynot

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Unsuccessful work done to cure cold rads

namsag

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