air trapped in boiler circuit

[cypher007]

ive had an old pumped CH gravity HW system changed to an unvented indirect fully pumped, using the gravity 28's for a flow and return. they moved the pump from above the boiler and put it in the cupboard upstairs where the cylinder is. the ch and indirect coil are still header tank fed.

the problem ive got is there seems to be a large airlock in the 28's. the plumber seems reluctant to remove said air, saying its normal to sometimes have air in the system. the trouble is the boiler keeps cycling but the rads and hw don't seem to get very hot. in fact if we put the hw and ch on together the hw doesn't get very hot at all.

so whilst looking at the manual for the old boiler, I noticed the gravity connections are normally capped. would the fact they have used the gravity feeds instead of the ch flow and return cause the airlock/poor heat up that were experiencing?

heres a pic:

 

[twgas]

Can you post a picture of the pump, motorised valve(s) and the pipework around that area.

 

[stardanny]

Is the boiler a Ideal Classic?

If yes, the pipe work is wrong, from left to right,

pipe A ( gravity flow ) should be capped.
Pipe B ( pumped return ) this is the one where all heating and hot water return to.
Pipe C ( gravity return ) should be capped.
Pipe D ( pumped flow ) this should go to pump and any motorised valves.

If left on gravity tapping, you will get poor heating.

Daniel.

 

[cypher007]

last night I went through the manual to check the connections. the plumber, who is gas safe, I call him a plumber but im beginning to wonder, has connected to the boiler back to front. so the flow is going down across the heat exchanger. probably the air is getting forced into the heat exchanger where it gets stuck, until the pump turns off, then it bubbles back up the return pipe.

stardanny I don't know how you figured it was an ideal classic but it is, an RS250.

incidentally are the gravity tapping's different inside the heat exchanger? I wondered if they might have a different internal arrangement.

anyway plumbers coming back Monday to fix it.

 

[cypher007]

Can you post a picture of the pump, motorised valve(s) and the pipework around that area.

picture of tank and stuff:

please tell me if there are any other Fups, as ill take him to task when hes sorting the other mess. also I didn't realise unvernted was supposed to be lagged by the plumber, he didn't, but I did it before I found out he should have done it.

 

[cypher007]

p.s. there's no restriction on the cylinder coil return, should there be? as I would have thought the water when the hw is calling and ch will just rush round the hw coil.