Radiators not all getting to temperature after fitting new boiler & new radiators

[RoyLittle0]

Hi All,

I am having a few problems with my radiator system, I have had a new boiler fitted earlier this year and I have also fitted an additional radiator as well as rerouting the pipework to another radiator, this was all earlier in the year, but it's not until now the temperature has dropped that I jhave noticed the problem.

My problem is that one room isn't getting to temperature, I have one radiator which is noticeably cooler than all the others on one that is slightly cooler than the others, both are new and in the same room, they are fed from above indipendanly tee'd into a 22mm pipe with 15mm pipe (Close together).

The area that I think is the problem has 4 radiators Tee'd off in a close location to each other, probably they all Tee off within a 500mm area of the 22mm main pipe, could this cause one radiator to be bypassed by the main flow and just receiving a trickle from the Flow.

I have tried various things like turning radiators off and balancing the system which has improved things but not solved them, any thoughts?

The system is:-

• Combi Boiler "Potterton Titanium 33"
  22mm pipework for Flow and Return
  15mm Branch pipes to each radiator
  underfloor heating system
  It has been Flushed
  all radiators have been balanced to 1/2 turn on lockshield
  15 Radiator system
  Mainly all TRV's

 

[joni os]

If all rads have been balanced, as stated, then some rads would not be cooler than others unless something has blocked flow since, or valves are sticking. Remove heads of TRVs and ensure pins move freely. Close all hot rads and if cool rads then heat up, you need to rebalance system. CROPPIE's REBALANCE GUIDE is the definitive bible.

 

[kris]

Hi there Roylittle and welcome along, irrespective the size of system as aslong as the boilers big enough to handle said amount of rads then aslong as its correctly balanced then you shouldnt have bypassing , you may get bypassing if incorrectly balanced though,,,,, like said below double check that the pin / thermostatic valve is working correctly , also the danfoss ones have a directional adjustment , depending on direction of flow you adjust the grommet to same direction the heats traveling , ( only with danfoss),,, also when you taped up the radiator valve insert did u make sure you didnt cover the internal hole with ptfe tape which can easily be done if not carefull, you may have a bit of trapped air however prob not as pressurised,
Id close all but that 4 to see if it fully heats , if it does then the problem is circulation / balancing , get an engineer to make sure the automatic air valve on the pump is open,

 

[RoyLittle0]

Thanks for the replies,

The TRV's are not Danfoss and the pins are not sticking, I did have one stick closed but that is a different rad and now fixed.

I can remove the rads to check if PTFE is covering the end but this will be a last resort as I was quite careful fitting them, but an option

I will close off most of the rads and see how hot the ones in the cold rooms get, the other one of the 4 which is in the bedroom gets very hot.

When I balanced the system I turned off all radiators apart from the ones that were cold and then opened up the lockshields by 1/2 turn, which certainly improved things. where can I get hold of a copy of CROPPIE's REBALANCE GUIDE.

 

[joni os]

Hi Roy.
Should have read "CROPPIE'S BALANCING THREAD" and link can be found in day old post under "Too many rads", reply 2.
Sorry my IT skills do not allow me to put up direct link.

 

[Dotty]

Hi Roy.
Should have read "CROPPIE'S BALANCING THREAD" and link can be found in day old post under "Too many rads", reply 2.
Sorry my IT skills do not allow me to put up direct link.

Mine are. .....

http://www.ukplumbersforums.co.uk/central-heating-forum/87115-croppies-balancing-thread.html