Underfloor Heating Issues

[Kryptonite]

Hi All

Issue
I have had underfloor heating fitted about 10 years ago and all was working well. I have been having issues with 3 zones not heating up downstairs and 2 zones not heating upstairs recently.

Setup
I have a 12 port manifold downstairs, and a 10 port manifold upstairs, towel radiators are connected to upstairs UFH. I have just recently replaced the entire manifold downstairs as of this issue, grundfos pump connected to the downstairs manifold and original wilo to upstairs manifold. I have a Worcester Bosch 40kw boiler with a Grundfos magna pump aswel as another smaller grundfos pump feeding.

The upstairs/downstairs manifold work independently aswel as the hot water independently through brand new 2 port zone valves. I have tried running downstairs on its own for a while without anything else on.

The plumber who has recently replaced the downstairs manifold has stated there is definitely no air in the manifold. The pipes were powerflushed downstairs before fitting. However there are 3 zones not heating up, the inlet pipes are hot however the return pipes are cold. I have tried balancing etc but it seems like its not circulating. Same issue with upstairs where-by 1-2 zones are not heating up.

I desperately need some help getting this sorted as I have run out of ideas and money on parts. All other rooms are getting hot as expected.

Please can someone shed some light, Thanks!

 

[BenH]

I can't help but I'm interested in the solution for this. BTW what kind of room thermostat you have there? Do they have a battery in them? it might need a battery change after 10 years. And do you know for sure that the relevant actuator(s) on the manifold is(are) open when heat is required?

 

[Kryptonite]

Hi

Upstairs Ufh manifold is run with 1 stat and downstairs Ufh with another stat. All actuators are open by default.
I can feel all flow pipes get very hot however the zones where there's no heat the return are cold

 

[Synergy]

Start by isolating all the circuits that are working at the manifold and see if you get flow through the ones that arent working. Depending on the type of manifold you have you will have independant thermostatic heads on each curcuit if this is the case just turn each head down on the working circuits. If you dont have this type of manifold you may have a visual flow vial that can be turned down to adjust the flow around the circuits. Basically they are only 3 things that can be wrong with it 1. The pin is sticking on the thermostatic control to the circuits that arent working. 2 the circuit is still restricted with sludge. 3. The system hasnt been balanced properly. The 3rd option is the most likley i would have thought without seeing it due to the manifold change. Some pics of the manifold would help if you arent sure what i mean

 

[Kryptonite]

Thanks for getting back to me.

I have attached some pictures of my downstairs manifold and boiler system.

Also I have just tried to shut off all zones bar the ones that are not heating up with no luck, however my boiler temp was going very high when i did so I quickly opened them back up again.

 

[jonnyswamp]

Turn off the blue and red iso's and refill each circuit in turn with a hose from your cold mains, making surer that each circuit is connected to the right valves
Let the water run through each circuit until water runs clear of bubbles out of the drain hose(5 mins or so per circuit should do) it will ensure all are full and eliminate blockage problem