Smiths ss5 plinth heater not getting hot water

[lmhud]

Our old plinth heater stopped blowing hot air so as we got a new kitchen we plumped for a new smiths ss5 plinth heater, the heater works on cold but the supply pipes are not getting hot.
I have turned all the rads off and hoped it would force the hot water through to the heater but it didn’t work, the 2pipes that supply the heater in the next room are warm at the top turning cold as you move along the pipes. I thought if I put the heater over a large bowl and open the bleed screw on the heater it would eventually start to run hot which it did, so I locked up the. Bleed screw and left it for 20 mins but rather than the heater bursting into life the pipes just went cold again.
Any advice please

 

[dang32]

i would guess one of the flexible hoses is blocked. i bet when the heater was changed, the old hoses weren’t

 

[lmhud]

i would guess one of the flexible hoses is blocked. i bet when the heater was changed, the old hoses weren’t

How do I unblock it

 

[dang32]

remove them and fit the new ones that would have been supplied with the new heater

 

[lmhud]

New braided flexible hoses have been used.

 

[ianmcd]

Some of the braided hoses have small service valves on them to allow the plynth heater to be removed for servicing without draining, if your have these make sure they are open, some pics of what you have would help

 

[lmhud]

Thanks all. They had used the old flexible connections instead of the new ones that came with the heater, I swopped them and found old ones were blocked. Which is probably why we thought the old heater was broken. With new flexible pipes it’s working now.