2 radiators out of 10 stone cold

[shadybrady]

I have a Vokera Linea 28 Combi Boiler in the garage.

The house is two storey with 5 rads upstairs and 5 downstairs.

I replaced the cr*p valves on all the radiators (cheap turn valves) with Pegler Terrier 2 TRVs and new lockshields.

I flushed the system, and removed all air from all radiators, set all lockshields fully open and all TRVs to 5.

All the rads are centrally controlled by a Honeywell CM67 digital thermostat in the hall.

My problem is that when I fire up the boiler, (setting the thermo to 21 to make sure the heating stays on for a bit), all the radiators come on boiling hot EXCEPT the two living room radiators that are STONE COLD.

The radiators have been bled fully - they have been removed and flushed when the valves were replaced, but both in and out pipes are stone cold and they are not heating up.

I have checked the TRVs are not stuck and that water is flowing in and out - ANY IDEAS????

 

[Gasman1015]

The system needs balancing. Shut down the rads that are working firstly, using the lockshields, to ensure flow.
Then start opening other rads by opening lockshields by approx. two turns
Water always takes the easiest route.
This is only basic to get your rads working and not comprehensive balancing, which requires measuring your flow and return temperatures.

 

[shadybrady]

I always though that you didn't have to balance a system with TRVs??

Could I just set the TRVs in other rooms lower to restrict flow as some rooms will have them set lower as they are unused / used not as regularly??

Do i have to adjust all the lockshields ??

 

[breezer]

i have my coat at the ready, but do all rads now have a trv? if so does boiler have a bypass valve? if not oh dear (one arm goes into coat sleave)

 

[shadybrady]

The bedroom radiator has not had its TRV fitted until I put the bathroom towel radiator in, as I know that if all rads have TRVs the system can end up completely locked for water flow.

Also on another note I read somewhere that you shouldn't have a TRV fitted where the thermostat is - is that true?? If so need to remove the thermo head and replace with the simple turn handle.

 

[breezer]

as far as i know, you are right regarding stat / trv stat will stop boiler, but if trv closes first stat wont stop and all trvs will then close (eventually) leaving water no where to be pumped as boiler is still on and pump running, but some boilers ahve a built in auto by pass to compensate (breezer takes arm back out of sleve)

 

[shadybrady]

The Voker boiler does have an in-built by pass so I am ok on that front.

So do you recommend removing the TRV from the rad near the thermostat and then just going round adjusting all the lockshields to get the system balanced?

 

[Gasman1015]

Yes, remove the head, no need to change the valve.

 

[shadybrady]

Do I still have to adjust all the lockshields on the rads to sort out temperature imbalances?

 

[Bahco]

Do I still have to adjust all the lockshields on the rads to sort out temperature imbalances?

Just for you mate, try THIS

 

[ChrisR]

Certainly you have to gaet the flow about right by balancing. It isn't as critical with TRV's though.

If the rad right by the boiler is say in a bathroom - a towel rail with the trv wde open, lots of flow will go through the one route. If someone's left 2 windows open the room may have trouble getting to the 28C or whatever the trv would need. SO the rest of the house has trouble heating up. Once the boiler is up to temp, it turns off.

Also, you would expect noise from the trv if not the pipes, because the flow would be so high.

Where the wall thermostat is,you can just leave the trv wide open, unless your stat is set above (in this case) 28. Quite often you can use a range-setting pin to stop the trv being turned down.