Understanding my heating system?

[kedsy]

I am quite new to plumbing and dont know much about heating systems. I am trying to figure out what type of boiler system I have. I have a baxi back boiler with a hot water storage tank. From what I have been reading I think it maybe indirect but have a few queries.

The hot water tank i have is the same as this one on the right

http://www.diydoctor.org.uk/projects/domestic_hot_water_systems.htm

1. Do all indirect boiler systems have to have 2 cold water tanks in loft or can they have only 1 (as mine does).

2. The cold water tank in the loft is feeding the cold water to the hot water storage tank (could this T off somewhere for the heating too?) There is a vent pipe fed to the tank also.

 

[ollski]

Probably primatic

 

[kevplumb]

primatic single feed cylinder

 

[kedsy]

Thanks, just been doing some more reading and have come to that conclusion also

 

[MANDATE]

A 'primatic' cylinder was introduced about 30 years ago. within it there is a set up basically comprising a inverted cone and a tube. The idea being that water rising in the tube will overflow into the cylinder and when the level reaches the bottom of the cone it will start to compress the air trapped in the inverted cone and create a bubble. The tube is tall enough to ensure the water level in the cone is well below the top of the tube. So the primary and secondary systems are separated by the bubble and there is only one entry point for the water so only one water tank is needed.
This is the only case I'm aware of where a indirect system not having two water tanks. There's not many of this type around, the idea did not catch on! why I don't know? I think it's the uncertainty that the bubble may have burst somehow and the two systems may not be separated.

 

[kevplumb]

shed loads of them here mate we pull about one a week out

 

[ollski]

There's not many of this type around, the idea did not catch on! why I don't know? I think it's the uncertainty that the bubble may have burst somehow and the two systems may not be separated.

can't add inhibitor or any chemicals, take a lifetime to drain and refill, are a stupid idea etc, etc. Unfortunately thousands of warm air / circulators round here were installed as primatics before anyone realised they were more trouble than they were worth.