Two Radiators Not Working on a 1 pipe System

benedictm · 10 Dec 2008

Hi there,

Not an experienced plumber here but know what i'm doing to a degree. In my flat there is a fairly old 1 pipe system. Two of the radiators seem to not be working. I have:

- bled them
- checked the valve's on both sides (they open freely with pliers)

The pipe underneath that feeds them is nice and hot and the radiators before and after the two broken ones are working fine.

Am I missing something here?

Thanks,

Ben

Agile · 10 Dec 2008

Its difficult for a one pipe rad to not work.

But as in all cases there can be a blockage.

If its a half modern system you could disconnect the rad and see if the valves will deliver water into a bucket.

Thats the Bucket Test!

Using pliers on a rad valve implies that you dont know what you are doing!

Tony

benedictm · 10 Dec 2008

That's what I thought. Looking at it I can't see an obvious way to remove a rad without draining the system.

I'll have a proper look at that this evening and am also going to try turning all the other rads off to see if that might clear any blockage.

Also, the only reason I had to use pliers, is the plastics 'tops' on the valves have worn down so don't turn the valve themselves. That makes sense right?

Agile said:
Its difficult for a one pipe rad to not work.

But as in all cases there can be a blockage.

If its a half modern system you could disconnect the rad and see if the valves will deliver water into a bucket.

Thats the Bucket Test!

Using pliers on a rad valve implies that you dont know what you are doing!

Tony

Agile · 10 Dec 2008

Turning the other rads off on a one pipe system is unlikely to have much effect.

Tony

benedictm · 10 Dec 2008

Agile said:
Turning the other rads off on a one pipe system is unlikely to have much effect.

Tony

Ok, well I guess taking the rad off and checking for blockages is the way forward.

I'll try that this evening.

If there isn't a blockage what'd next?

thanks very much for your advice by the way.

Agile · 10 Dec 2008

I would have to say there MUST be a blockage!

There is another trade trick that you could try! Thats to freeze the pipe which by passes the rad so that ALL the one pipe flow has to go through the rad ( of course done with pump on but boiler off! )

That might possibly force the blockage out.

But in most cases its a machanical blockage removal thats needed.

On a one pipe the pipe has to be completely clear, a partial flow is not adequate.

Tony

benedictm · 10 Dec 2008

Ah that sounds a good trick! What would you freeze the pipe with?

If this doesn't work I think I may need to get a proper plumber in - taking rads off is, I think, a bit beyond my skills...

Agile said:
I would have to say there MUST be a blockage!

There is another trade trick that you could try! Thats to freeze the pipe which by passes the rad so that ALL the one pipe flow has to go through the rad ( of course done with pump on but boiler off! )

That might possibly force the blockage out.

But in most cases its a machanical blockage removal thats needed.

On a one pipe the pipe has to be completely clear, a partial flow is not adequate.

Tony

Agile · 10 Dec 2008

I said that its a trade trick that someone with an electric freezer might do.

Its unlikely to move any blockage without chemicals.

Its a dismantle job !

Tony

simond · 10 Dec 2008

You haven't got TRVs on this rad, I assume?

benedictm · 10 Dec 2008

simond said:
You haven't got TRVs on this rad, I assume?

one does, the other doesn't.

skowi187 · 10 Dec 2008

we had a similar problem the other week where the water was just passing through the pipe below but not actually flowing into the radiator. we powerflushed it and still no heat. the way we got around this problem on this job was to cut out the middle bit between the two tails going to the rads therefore forcing the water through the radiator. make sure there are no t.r.vs either as they have a more reduced bore than a standard lockshield valve and the water will travel by its easiest route.

seco services · 10 Dec 2008

skowi187 said:
we had a similar problem the other week where the water was just passing through the pipe below but not actually flowing into the radiator. we powerflushed it and still no heat. the way we got around this problem on this job was to cut out the middle bit between the two tails going to the rads therefore forcing the water through the radiator. make sure there are no t.r.vs either as they have a more reduced bore than a standard lockshield valve and the water will travel by its easiest route.

that isn't no good in the long run is it.

skowi187 · 10 Dec 2008

that isn't no good in the long run is it.[/quote]

customer would not foot the bill to have the system changed to 2 pipe what other option did we have spent 2 days doing the most precise balancing there is and still only getting luke-warm water. there was two options leave the radiator cold and rile the customer or do what we did.

Agile · 10 Dec 2008

If the radiator had even worked, then something had changed and restricted the flow to the rad.

In that case doing anything which does not solve the underlying problem is unprofessional and would not be supported by the CIPHE but then I dont expect you are a member!

Tony

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Two Radiators Not Working on a 1 pipe System

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