Two radiators not getting hot

[Richieduliban87]

Two radiators on my heating system. I believe the last two, are not getting hot.

There was previously a lot of air in the system which I removed. The boiler pressure is at 1.5bar, should I increase this?

I closed both valves on all the working radiators and still no luck!

 

[Mottie]

Have they ever worked?

 

[Richieduliban87]

Yes

 

[Madrab]

Leave it @ 1.5bar.

Firstly it needs investigation by removing the flow and return pipes and testing the flow/return for blockages. Can the pipework be exposed and checked for correctness?

What size is the pipework?

 

[Richieduliban87]

There does appear to be inadequate flow.

The pipes are 15mm except for the first 50cm or so from/to the boiler where they are 22mm.

I had my thermostat changed to a Nest thermostat a few months back. Could that have been a factor?

Cannot really expose all pipework but the pipework down from the boiler in the loft are fully exposed.

 

[JohnD]

.

 

[Richieduliban87]

Also I removed the only radiator in the loft. Were simple tees from the flow and return pipes. I cut its pipes as as close to the tee as possible and put blanking nuts. Wudve thought would improve flow if anything.

 

[Madrab]

I assume the supply to the radiator in the loft stopped at that radiator?

How old is the boiler?

 

[Richieduliban87]

Yes, I’ve solved it. Boiler is 3 years old. I did a boiler reset. And then instead of closing the three working radiators completely off, I left then one quarter turn open. They still get very hot but enough heat now gets to the remaining two. For some reason turning them off stops the flow for whole system. This will be annoying if someone wants their radiator off. Could there still be an underlying issue?

 

[Madrab]

How many rads, size of system?

Just sounds like you just need to balance the system correctly.

 

[Richieduliban87]

5 rads. Not sure about the size.

 

[Madrab]

Wow, you shouldn't have any issue feeding 5 rads with a 3yr old boiler unless they're like 60 meters apart. Sounds like there's a flow issue somewhere. Needs investigated.