1 radiator not draining

[andrewukr6]

Hello, draining central heating system for second time (first went fine). Hose to lowest rad, trvs removed so valves should be open. Drain feed stopped spouting water yet one rad is still bleeding through the top valve, I took a bucket from it! This rad also has a drain off valve at bottom which I attatched with some suction but it's not pulling through either.

Another rad at mid height was also a pain, it also had a drain valve but I did empty this one.

So what gives, all bleed valves open, draining valves open, yet its still pushing out of the bleed off valve in the top (I guess suggesting water feeding to this one).

Tried to find an old water pump but no avail, anyone got a suggestion its a bloody pain!

 

[Steelmasons]

Possibly the rad has been fed from a drop down which could explain the DOC fitted to it.

 

[terryplumb]

is the rad that will not drain on ground floor ? is the drain cock not letting water pass ? are you draining system again because you are having difficulty with some rads not getting hot ?

 

[andrewukr6]

its a bungalow so little height difference, however theres a few feet. All fed from a tank in the attic. 3 of the rads have drain off valves. Actually the reason I was draining was to fit honeywell evohome TRV's and the existing type was a push fit. Previously not all the rads would get hot at once but I beleived this to be that the system was not powerful enough to run all.

PS. Any plumbers / heating engineers familiar fitting evohomes?! It's beyond me and the plumber that looked at it thought it was beyond him, the existing system is apparently a bit of a mishmash!

 

[Terry lambert]

Yeah, there's loads on here that are Honeywell connected specialists, where about are you ?

 

[terryplumb]

still think rads are not draining because of blockage ,pipework or valves / drain cock. system not heating rads equally is likely in need of balancing . how many radiators are on the system ? and I guess the pipework to rads is 10 mm.

 

[AGAS]

have you any vents ( manual or auto?? )on the pipework in the attic as bungalows normally do

 

[andrewukr6]

thanks for these tips, I will check for vents. 15mm pipework. I will try to get them balanced, and as for evohome I'm based in Sussex - I will make a new thread for it!