open vented systems without a feed and expansion tank.

[jimbo639]

Hi, I would like information on open vented systems which do not have a feed and expansion tank and have a small cylinder approx a foot high and 8 inches dia,often situated above the hot water cylinder.This small cylinder has three pipes attached and a float type automatic air release valve, one of the pipes appears to be a feed from the cold water storage tank in the attic.It's function appears to be topping up the heating system automatically.Any replies greatly appreciated.

 

[danielp]

picture

 

[jimbo639]

Danielp,I will go back to the customer and take a picture next week.I am going to replace the boiler and they want to keep the existing system so I want to fully understand it.

 

[Mike Jackson]

I think it's some sort of variation on the primatic single feed cylinder system. Saves having a separate F&E cistern. Problem is it relies on an air gap to keep the two systems separate so you can't add any chemicals to the heating system.

 

[flat pack]

sounds like a servowarm company design.

what the name of the old boiler and age.
lots of these were put in the airing cuboard

 

[Bernie2]

Hmm

Sounds lika an old servowarm job. On some of their systems they used what they call a top up bottle instead of an F and E cistern.

 

[flat pack]

You also may find the pipe work may be silver colour.
this is crap pipe they used .
if you work on this it will cause you problems .
1/ fall apart in bits.
2/ or leak from pin holes.
3/ don't put any chems in the system you could be call back with leaks
uplifting floor boards etc.
4/ check it and pre warn your clients
5/ there a echo in the room

 

[jimbo639]

I think I have managed to attach a photo called 000_0203.jpg in attachments. Let me know if it has not worked!

Jim

 

[jimbo639]

Here is the over all photo.

Jim

 

[Mike Jackson]

Definitely an adaptor turning it into a variation on the single feed indirect system.

Mike

 

[Puddle]

This is a external primatic system fitted on the hot supply supply.This was fitted so that the hot water cylinder could have a pumped flow from boiler which you can not do on a primatic cylinder
As Mick says you can not add chemicals to system
due to room it takes up can not see why it can not be removed and small header tank fitted or system presurised

 

[jimbo639]

Yea i see what you mean, but has any one fitted a modern open vented boiler to one of these systems and did they encounter any problems? It would be very difficult to fit a feed and expansion tank to this particular system and changing it to a pressurised system would have potential problems as well.

 

[Puddle]

I have not fitted a modern boiler to this system but have seem as few pre He potterton suprima's and ideal classics on it
New boilers will work on this system ,no problem with updated controls but the problem is ,as mentioned,you can not put chemicals in system,and all new condensate boilers require chemical inhibitor in system to provent corrosion and electrolyis
between all differant metals now in system and boiler