New logic + central heating issue

[thorn]

Any help would be greatly appreciated

Just fitted a logic + today to an old open vented system. All piped up and pipework changed etc, but when it calls for heat, it won't flow from the boiler and the temp goes sky high and then cuts out. The old boiler flow in the cylinder cupboard is connected to the heating flow and the return is capped. Flow and return at the new boiler are correct way round according to the old boiler. ISO valves are open and the rad valves as far as I can tell are bidirectional.

have never had this problem before - stumped

any help or ideas
thanks

 

[oil gasman]

Any help would be greatly appreciated

Just fitted a logic + today to an old open vented system. All piped up and pipework changed etc, but when it calls for heat, it won't flow from the boiler and the temp goes sky high and then cuts out. The old boiler flow in the cylinder cupboard is connected to the heating flow and the return is capped. Flow and return at the new boiler are correct way round according to the old boiler. ISO valves are open and the rad valves as far as I can tell are bidirectional.

have never had this problem before - stumped

any help or ideas
thanks

hope u don't mind me asking been out of the industry a while , what is a logic plus please

sounds like a combi ,

thks mate

 

[Rickster123]

What boiler came out? Any non return valves on the system?

 

[thorn]

I was wandering about the non return valve possibility, I even changed the flow and return over at the boiler so in my mind cant see that being the issue. The cylinder cupboard had had a new pump and 3 port in the last couple of years by the looks of it. The cupboard has hot and cold (obviously), 28mm boiler flow, 28mm heating flow and 22mm return. Could these have been altered with the previous work making me link/cap the wrong ones?

 

[thorn]

Oil gas yes it is a combi and APP the old boiler was an Apollo 50si

 

[Rickster123]

Might need some floor up and trace back the pipework. If it was a bbu coming out it's not unusual to find a non return valve in boxing to the side. Same if there was a floor standing boiler removed from the kitchen. I'd start tracing back the pipework mate.

 

[thorn]

Luckily shouldn't be too hard to do that APP, all along the landing and straight to the kitchen and above boiler. Can you think of any reason that the 28mm pipes shouldn't be linked, and maybe it should be the 22mm linked? I've still got the pump and 3 port pipework in one big piece so I'm 100% sure on how it was and don't want to doubt myself yet!
thanks again

 

[Dannyboygas]

Sounds daft but is the pump turning ok? Had new boilers with various faults before. Don't they have a self diagnostic (limited I know) on the front display?

 

[thorn]

The pump is running as far as I can tell, haven't actually checked it electrically but the fan is running and it fires up so would have thought it wouldn't fire up if the pump wasn't running. Will check the pump properly tomorrow.
Regarding self diagnostics it doesn't come up with any fault, just says it is going into standby mode

 

[anz]

New boiler went into the cylinder cupboard?