F+E tank with no vent

[dom brennan]

hi i was just wondering if this is normal or it it was a mistake. the F+E tank never had a vent on it, we drained it down and it took 2 hours to get up and running. some of the air was coming though the cold feed to the primaries to the tank. I've had a look though my college books but can't find anything. thanks dom

 

[Dannypipe]

22mm cold feed off the tank? Combined feed and vent. Bit unusual but allowed on certain boilers.

 

[dom brennan]

i don't really know much about this kind of things but if the pressure got to much it would usually go back into the F+E tank, so does it go into the Cold water storage cistern but wouldn't that contaminated the hot water

 

[Dannypipe]

F&E is heating (primary)

Cold water storage is supplying your domestic hot water, via the cylinder, and cold tank fed outlets.

I assume the tank you are talking about is the f&e (smaller of the two tanks).

 

[Ollieg]

I think you may have a primatic system? Maybe?

 

[dom brennan]

but the primary is the same water in the radiators so if that pressure got to high for some reason i would go into the cold water storage or would this never happen i tried asking my employer but he just said he doesn't know

 

[Toxic Ted]

No Dom when the heating gets warmer it expands back into the f&e tank back through the feed pipe.

 

[Dannypipe]

Like Ted say's....the primary water in the rads will expand back into the the feed and expansion tank (smaller one) and isn't connected to the cold water storage tank (big one). So no chance of contamination.

Primatic cylinder is another thing to go into, but I don't come across very many.

 

[Dannypipe]

Also, your employer probably does know, but is too busy to explain it, which is common. Hence why this forum is helpful.

 

[dom brennan]

thanks so much guys i think i understand a bit more now

 

[Chalked]

Primatic cylinder.
The term 'Primatic' is a registered trademark of IMI.
Primatic cylinders perform the function of an indirect hot water cylinder with the primary services for a domestic heating system.


Primatic cylinders only use one supply cistern but functions as an indirect, automatically performing the duties of the feed/expansion tank in the double-feed system.


The working principle is based on the buoyancy of air; this considerable natural force is used to create the seals between the primary (boiler) and secondary (domestic hot water) systems.


Consequently, there is risk of cross-contamination between the hot water discharge and the central heating system, thus the use of treatment chemicals is not recommended.


If you only have one supply cistern, or your cylinder is marked Primatic, then you should not use treatment chemicals.

 

[tamz]

I think you may have a primatic system? Maybe?

How could it be a primatic with an expansion tank. Think about it. Google myson appollo install instructions (among others) and you will see a diagram. Btw the correct name for a primatic (which as the above post, is a trade name) is a single feed indirect.