Rads fed from return pipe!!!

[JohnnyDollar]

Hi all,

Looking into a problem on a brand new install where 12 of 14 rads work normally but 2 are working the wrong way round where the incoming water is from the return!!! Any ideas? More info available but don't want to bore people.

Any help greatly appreciated.

JD

 

[Plumbstar Tom]

How do you mean

Is it coming through the side of the rad that has the TRV and hand wheel valve?

What your saying doesn't make sense to me fro 12 rads to work from the flow but then 2 have feeds from the return

The water would not make a complete circuit if that is so and would not circulate?

 

[JohnnyDollar]

Hi Tom,

Thanks for getting back so quick. I know I'm baffled, it's a twin pipe sealed system on a combi boiler and all valves are reversible with flow direction.

I can feel one pipe much hotter (when first started) so surely must be the flow. But both rads fill from the cooler pipe. The 2 rads in question only get hot once the rest are, again making me think the returns feeding them.

 

[doitmyself]

I can feel one pipe much hotter (when first started) so surely must be the flow. But both rads fill from the cooler pipe. The 2 rads in question only get hot once the rest are, again making me think the returns feeding them.

How do you know the two rads fill from the return?

If all rads are not heating up at the same rate, the probability is that the system is not properly balanced.

How to balance a CH system

 

[JohnnyDollar]

When I've turned the heating on from cold I can feel one pipe get hot first - so I'm thinking this should be the flow. I can't trace it properly as it goes into a ceiling void where there's no access.

The other rads all heat up at approx the same time as I've managed to balance them. Then when I check the cooler pipe, which I would expect to be the return pipe, I could feel the tail to the 2 problem rads getting hot and then the rads before the flow tail got warm.

Something seems to be fundamentally wrong but I can't figure it out so any help is massively appreciated.

 

[doitmyself]

Shut off all "good" rads and then monitor the temperature of the rad pipes of the two "bad" rads. That will tell you which is flow and return.

Incidentally do any of the rads have TRVs? If they do, remove the head on each valve and check that the pin is not sticking. Then check what happens to the heating up when the TRV heads are removed.

 

[JohnnyDollar]

Thanks for all the advice and the link to the balancing info. I'll try all of the above and let you know.

Many Thanks

 

[moony]

check the trvs are set to the right setting f/r if they are the 2 way sort

 

[Billy Bob Bob]

you have a airlock knock all good rads of and leave the boiler plug away at the other 2 for 30 mins this should sort it also check balancing