back boiler and combination cylinder questions....please help

[kay-jay]

right

went to swap 2 rads today! draining down rolls meself a ***, stood in garden waiting for drain down to finish.

house and rads and pipes stone cold! thinks to meself drain down seems to be taking a while (its a bungalow) then i notice theres steam coming off the water coming out my hosepipe, i'm thinking eh! scratches my head a bit then goes and looks in loft.

f and e tank not draining at all, but cylinder is!!!!

so initial thoughts were tee blocked where f+e tees into heat circuit and some wazzer has teed into the hot distribution adding a rad, thinking it was either flow or return.


question

cylinder looks like a standard combination, but could it possibly be a primatic? and if the feed from f+e is blocked would the suction created during drain down be sufficient to pull the air bubble in the primatic and thus drain rads and hot water header tank? or am i most likely correct in assuming someone has teed the hw into the heating?


also there was no open vent over the f+e, so where the buggery is the expansion going? is there some kind of ancient system which would see expansion elsewhere?


your thoughts would be greatly appreciated.

KJ

 

[stevetheplumber]

if you have two tanks its not primatic as they feed from the cws
if its a combination cylinder that would feed from its own built in tank
without pics its hard to say more

 

[kay-jay]

turned out it was a 'fortic primatic' few and far between but in existence non-the-less.
a quick search on internet proved that it feeds off hw tank and expands into the primatic air bubble. so problem solved. f+e must have been a hangover from previous open vent system.
cheers

kj