New rads

[NewhouseOldhouse]

Hi

I have installed new rads with pipes running across loft then down walls to rads.

I took feed of 15mm flow/return and t'ed off for each rad.

The first rad is heating up fine but rest are not.

Pressure is at level on system and I have turned other 4 rads off unscrewed valves at top of each rad and open valves.

Couple of them heated then went cold again.

Any ideas?

Thanks

 

[Harry Bloomfield]

15mm is too small for the main flow and return pipes, if that is what you have installed.

 

[NewhouseOldhouse]

15mm is too small for the main flow and return pipes, if that is what you have installed.

Main flow/return is 22mm I have took 15mm feed of it.

 

[NewhouseOldhouse]

I meant to say the flow pipe along the loft is hot but return is cold, air in system??

 

[NewhouseOldhouse]

Would 2 of these on the flow return resolve the issue?
Flamco Flexvent R½" Automatic air Vent, Radiator air Vent, Boiler Airvent Valve 27740 https://www.amazon.co.uk/dp/B00GXNNGPY/ref=cm_sw_r_apan_i_HX003BNGJVR0PR2C183G

 

[Harry Bloomfield]

I meant to say the flow pipe along the loft is hot but return is cold, air in system??

Yep, an airlock where the pipe loops up to the loft.

 

[Bod ...]

I'd say it was air as said above. If the radiators are of a designer type then the flow could be on the wrong side.

 

[gas112]

turn off every rad apart from just one of those thats not heating and that will force the air out the pipes then repeat for each of the rads not heating up

 

[CBW]

Check for air as well as balancing.

 

[NewhouseOldhouse]

I'd say it was air as said above. If the radiators are of a designer type then the flow could be on the wrong side.

That's the radiators I have installed

 

[NewhouseOldhouse]

turn off every rad apart from just one of those thats not heating and that will force the air out the pipes then repeat for each of the rads not heating up

Tried this and yes radiator that wasn't heating did heat but when all back on again went cold.

How long do you have to leave the not working radiator open for?

 

[NewhouseOldhouse]

Check for air as well as balancing.

How do I do that?

 

[gas112]

Tried this and yes radiator that wasn't heating did heat but when all back on again went cold.

How long do you have to leave the not working radiator open for?

leave it on a good 20 mins plus making sure the return get hot as well if your system is a pressurised one take the pressure above two on gauge also

 

[NewhouseOldhouse]

leave it on a good 20 mins plus making sure the return get hot as well if your system is a pressurised one take the pressure above two on gauge also

Pressure is 1.2 when heating not on then 2 when heating is on that OK?

 

[gas112]

Pressure is 1.2 when heating not on then 2 when heating is on that OK?

take it to 2 with heating not on