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?

 

[tolly]

You say you capped the return, I presume you mean you have capped off the cylinder return with it being the last tee before return goes back to boiler. You sure you have not capped off the wrong pipe hence it not being able to circulate

 

[Dannyboygas]

I don't think I should put it here so not gonna go into how but I would vent it and check incase it's been sat in warehouse for a few months.

 

[thorn]

Boiler is in kitchen same location as the old one. Yes tolly you are right, I capped the 22mm cylinder return. I'm totally certain I capped the return, I always marker pen everything up before I take anything out to avoid situations like this!

 

[thorn]

Dannyboy, is this something you have encountered before?

 

[Leo21]

Have you fitted a filter? And checked pump spinning?

 

[tolly]

I assume the old vented system worked before being taken out...worth checking pump hasn't seized up from sitting in stores too long deffinatly. quick tap with a sledge hammer if it stuck lol

 

[thorn]

Yes it's got an Adey micro filter in the cylinder cupboard (couldn't feasilbly get it by the boiler), if the pump wasn't spinning would it still fire up? I should have checked pump properly it but will do tomorrow

 

[Scott_D]

Magnaclean valves open?

 

[Dannyboygas]

I fit Worcesters 90% of the time so cannot comment tbh. Have fitted a few logics before, not bad I don't think. Especially in comparison to the isars, and worse still the Istors! Had a motor problem with a Worcester, once had a pump seized years ago on a 105e my dad fitted when I was an apprentice.

I think in the technological set ups of new boilers we instantly look for something complicated before checking the basics! I know I have done before anyway. Good luck with it mate sure it will click tomorrow.

 

[thorn]

Yes Scott they are open, I double checked! First thing I'm going to do is check the pump properly and then start taking boards up

Thinking about it, it does seem like a flow issue as the heat does go up the flow pipe but only by conduction, i.e very slowly. It's acting like the valves under the boiler are off but they aren't.

thanks

 

[samwilko]

Definitely check the pump, I ve had a couple of them where the spindle of the pump has stuck from it being sat in merchants for a while. Physically take the pump out and check it's spinning freely. The couple I ve had just needed an initial turn by hand. A light tap with something wasn't enough to get them going.

 

[samwilko]

Is it going off on overheat?

 

[Rickster123]

Is the hot water working ok?

 

[hammers4spanner]

You say the valves on this boiler is defo open however on these models they look open but are closed i find them bit arse about face

maybe worth a double check

i assume you took the rubber bungs out before fitting valves just a thought

 

[southcoastboile]

Probably a stupid idea but pump valves open?