newbie here ... quick primatic question

[zigman]

Hi, i have two tanks in my loft. the cold water tank and a small expansion tank. the small tank collects hot water when i have my central heating on and my pump on for the back boiler in my open fire. I doesnt collect much, just to when the variable recirc pump for the fire sorts its self out.

I was looking to treat my central heating sytem to keep it healthy. However the small expansion tanks just overflows to drain, ( if needed and not that it has so far) and does not feed the water anywhere, i.e to the boiler.

Therefore im guessing i have a primatic system and therefore cannot add chemicals to the system.

Im I right?

thanks in advance

 

[Armo74]

If it was a primatic system you would only have one large tank in your loft and wouldnt be able to add chemicals as that would also feed your hot water cylinder.

 

[45yearsagasman]

No is the short answer. As you have a small expansion tank in the loft your cylinder will be indirect and therefore ok to chemically treat your system.
Getting hot water into the exp tank indicates a system fault.Most likely to be a blockage.

 

[martyndc88]

doesnt sound as if its primatic, its prob indirect, and the hw in your tank is a problem (CH water expanding 2 much) may bee as simple as the hook on the expansion going into the tank not bing high enough. is there a 22mm pipe coming off the bottom of your tank going to the AC.? and its not going to a drain because when the heating cools down the added water in the tank goes back into the system

 

[bengasman]

Hi, i have two tanks in my loft. the cold water tank and a small expansion tank. the small tank collects hot water when i have my central heating on

No, it does not.
The small tank feeds you ch system, and the pumping over indicates the common back boiler problem: badly corroded and blocked.

 

[zigman]

thanks for all the replies

the small tank has no outlets on it except for being connected to the overflow drain from the cold water tank.

there is a water feed into it via a ball cock from the cold water tank.

this is what is confusing me, i was expecting to see some sort of a bulkhead fitting on the small expansion tank taking a feed to ch if needed.

i must add here that it is an old 50's council semi that has im sure been not to well modernised over the years as regards various systems.

 

[mysteryman]

We need a pic of your Irish layout!

 

[expertgasman]

the small tank has no outlets on it except for being connected to the overflow drain from the cold water tank.

there is a water feed into it via a ball cock from the cold water tank.


You may find that the outlet to the CH is on the BOTTOM of the header tank. If the water isn't clear enough to see, get you hand in and feel around.

Would advice gloves and a wash afterwards.

 

[bengasman]

thanks for all the replies

the small tank has no outlets on it except for being connected to the overflow drain from the cold water tank.

there is a water feed into it via a ball cock from the cold water tank..

Think about it for one second. What would be the purpose of a tank with a coldfeed and no outlet?

 

[commercialman]

Think about it for one second. What would be the purpose of a tank with a coldfeed and no outlet?

Some old school plumbers used to do this years ago when installing primatic cylinders , have a think about it. .....crazy idea to say the least.

 

[bengasman]

Must be very old school, I'm no kid anymore but never seen this; are you sure you read the statement correctly? => a tank with no outlet.

 

[picasso]

I have had a think about it and as ben said I cant see any purpose of a second tank with no out let, so whats the logic behind it (if there is any)?

 

[commercialman]

An additional expansion cistern was fitted along with a seperate open safety vent , the reason being if boiler stat failed open safety vent would discharge 'dirty' water from central heating system into 'dry' cistern as opposed to main cold water cistern , another reason for OSV was to relieve any pressure in system that could potentially destroy the 'air bubble' & contaminate hot water supply.

My old college tutor was one of the 'old school' boys , i guess you could take it up with him but i would imagine he's six foot under by now.

 

[expertgasman]

But why the cold FEED into the tank?

 

[bengasman]

But why the cold FEED into the tank?

Indeed.
Either a complete muppet installer, or op did not look/describe accurately.