How bad is this system?

[matt-l-p]

Generally works okay, but bubbling when on hot water only. How can I easily alter this to works better?
Please see picture

 

[SJB060685]

I don't like that setup at all, especially as the vent is compromised.
Seal the system would be my advice, unless you want to recipe a lot.

 

[ShaunCorbs]

Old gravity set up either needs moving eg feed and vent or as above sealing

 

[Ric2013]

Very bad. Someone has reversed the flow to allow a quasi-S-plan system but that means the cylinder coil flow and return are reversed, the cold feed and vent are reversed, and (could be a serious safety issue) the open vent isn't really open. Needs a competent plumber to modify that into a proper S plan.

 

[matt-l-p]

Thanks for your replies, what about this set up in the picture? Or would it be a waste of time. The pump and valves are right next to the boiler,
so would be really difficult to get the vent and feed before the pump

 

[SJB060685]

That's no safer mate. The vent needs to be off the boiler flow and before the pump ideally you will position the cold fill there as well with the vent first and the cold fill after with a maximum of 150mm between the two centres of the tee's.

 

[ShaunCorbs]

Like this right one eg c

 

[matt-l-p]

Thanks allot, looking at it, will probably be easier to seal the system possibly

 

[Ric2013]

What boiler do you have? What systems are safe and possible depend on the nature of the boiler itself and its inbuilt safety features.

 

[matt-l-p]

 

[SJB060685]

Your oil boiler is suitable for sealing the system.

 

[matt-l-p]

Thanks everyone, plumber been round and agrees seal it. I'll let you know the result

 

[SJB060685]

I would not install the pump and expansion vessel as shown in the image though. The plumber if he/she understands it will know where to position.

 

[matt-l-p]

Okay , I showed him the diagram and he already said about putting vessel on the return side

 

[SJB060685]

Okay , I showed him the diagram and he already said about putting vessel on the return side

Yes for a number of reasons, perhaps most the function and durability of the system is that the vessel should be on the return and with the pump shortly after, this way you will create a positive pressure through the boiler and throughout the system where it meets the vessel connection and point of no pressure change. This will ensure no air is drawn into the system, as well as not allowing any dissolved gases from being drawn from the fluid. Positioning the vessel on the return will also prolong the life of the vessel diaphragm as its not subjected to the higher temperatures.
Whilst the engineer is making the adjustments I would strongly advise a filter installed on the return as well and pay attention to the quality of water when draining down. Your system may benefit from a flush with chemicals.