No expansion tank for radiators?

I need to fit a new radiator into my bathroom. My CH system is a 20
year old gas boiler a HW tank and cold water tank in the loft. I was
expecting to find a central heating cold water tank but I dont have
one.
Where does the water for my radiators come from and how is it heated.
I want to work out what I have to do to drain my radiators to fit the
new one.
Could the radiators just use DHW? Will my HW tank have a seperate
circuit for heating the radiators?
Reply to
405 TD Estate
|I need to fit a new radiator into my bathroom. My CH system is a 20 |year old gas boiler a HW tank and cold water tank in the loft. I was |expecting to find a central heating cold water tank but I dont have |one.
Your system could easily use the existing CW tank for both CH and HW. It could even use the same outlet pipe and split further down. Trace the pipe.
|Where does the water for my radiators come from and how is it heated. | |I want to work out what I have to do to drain my radiators to fit the |new one. | |Could the radiators just use DHW? Will my HW tank have a seperate |circuit for heating the radiators?
Probably a standard indirect system. How many pipes are connected to your HW tank?
Reply to
Howie
No, reading it again I'm not! I think there needs to be more than commas :-) From the posting I thought maybe he was confusing the CH header with the HW tank :-)
Reply to
adder1969
Sorry the HW tank/cylinder is on the 1st (bedroom) floor, boiler is on the ground floor and there is a water tank in the loft which refills when hot water has been used.
So where do the radiators get their water from - how do I drain and refill them?
Reply to
405 TD Estate
In an earlier contribution to this discussion,
It seems to me that there are three possibilities:
1. There *is* a fill & expansion tank in the loft, but you haven't yet located it.
2. You have a sealed/pressurised system - in which case there will be an expansion vessel and filling loop somewhere.
3. You have a Primatic HW cylinder (a work of the devil!) which includes an internal partial interconnection of the primary and secondary circuits, such that they share a single header tank, and therefore cannot use inhibitor in the CH system.
Sounds like a bit more investigation is required in order to determine exactly what you've got. How long have you lived in the house?
Reply to
Roger Mills
It could possibly be a Primatic system. Both the hot water and heating circuit are fed from the same tank. The water going into the storage cylinder feeds both during initial fill up but then an airlock is formed that keeps the two circuits seperate. We had one that worked fine until the inlet bush started to leak.
There is a good illustration of one here
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Reply to
John Evans
On 9 Jan,
I would expect anyone with a primatic system over 20 years old to have had problems by now. They were never very successful at isolating primary/secondary water, as they could lose the bubble of air if the water got too hot.
Radiators on a primatic system of that age may be past their best as well, as inhibitor can't be used.
Reply to
<me9
I converted mine to a sealed system in the end, bypassing the filling from the HWC and fitting an expansion vessel and filling loop instead. It's still going as far as I'm aware. Rads were never any problem. It was a mains fed one though, not from an expansion tank.
Reply to
adder1969
My boiler certainly has the same connections as the Primatic one i.e. two at the botton one either side, one halfway up and 1 at the top - would any other boilers have a connection 1/2 way up?
There could be a small expansion tank hidden in insulation towards the edges of the roof but I didn't notice one when i bourded the loft outh though I did not do all the way to the edges.
Reply to
405 TD Estate

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