Old Central Heating Where is the filling loop?

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I have recently moved from a property with a combi boiler complete with pressure guage and filling loop which allowed me to alter the system, drain down and refill etc as needed. We have recently moved to a property that has seen very little updating for what looks like several decades with the exception of the boiler (Potterton Precission).

From what i can see it only has a feed, flow and return with no method of topping up. I am sure this cant be the case but cant find any method of filling or measuring the pressure, both of which i would like to be able to do for a number of reasons. Is there such a thing as a self filling system used in older systems?

I have attached photos of the boiler and hot water cylinder with what i think to be the pipe uses. Those that i don't think i know have been marked"?" Let me know if i am incorrect on any so i know what i am looking at.

Any help much appreciated.

 

[Burnerman]

Have you looked in the loft, Mr.P?
Methinks you’ll find a small header tank that keeps the boiler happy, and a large tank that supplies the copper cylinder with cold water, ready to be heated by the indirect coil within.
The little dead leg is a bleed to let any air out, so the boiler can heat the domestic hot water.
John

 

[ianmcd]

you dont have a filling loop or a pressure guage you have a gravity fed open vent system with as @Burnerman says you will have a small F&E tank in the loft, are you having problems with how it is working ?

 

[padstar]

There are 2 tanks in the loft. I wondered if it was the case that the 2nd topped up the heating system. So it is a self sufficient CH system? Are these common now days or reserved for older systems?

The boiler trips out every few days which i thought may have been a result of low/drop in pressure in the central heating but i guess not if it tops itself up.

 

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Are the pipes i have marked from the cylinder in red/hot serving the hot water or the central heating? What are the pipes marked in green?

I would like to remove a few rads and cap off until i get the full system replaced. How would i go about draining and refilling the central system?

 

[Burnerman]

It looks like you have the older, traditional open vented system, hence the loft tanks.
Looking at the picture with the green cylinder, the two white pipes on the right are from the boiler and provide the domestic hot water, which exits the tank from the top, heads downwards eventually but has an expansion pipe branch on the horizontal run.
Heating wise, the two port valves control the boiler heat to either the radiators or the HW tank, depending on demand.
John

 

[Burnerman]

Regarding radiator removal, closing both valves will allow the radiator to be drained.
The rad should automatically refill so long as the feed from the small loft tank to the central heating circuit isn’t blocked.
John

 

[Madrab]

You pipe on the left is the cold water feed into the hot water (hw) cylinder from the large cistern up in the loft. The green ? on the right is the boiler flow into the coil in the cylinders that heats the water in the cylinder and the one below it is the return to the boiler. Water out of top is your HW supply as already mentioned.

It's a tried and trusted CH system that, like most others have been about for years. It is gravity hot water though so it won't have the pressure that you have been used to with the mains hw from the combi.

 

[ianmcd]

Are the pipes i have marked from the cylinder in red/hot serving the hot water

That is the hw that comes out of your cylinder that comes out of your taps

What are the pipes marked in green?

the one in Green that goes in to the center of the cyl is the flow from the boiler to heat the HW in the cylinder coil,( edit ) the other is the cold feed from the Cold water cistern to the cold taps

You are asking far too many questions at the same time you will just get confused with all the answers you get, below the boiler what you call the feed pipe is the gas supply to the boiler.

Back to your problem what lock out code do you get when the boiler wont come on

 

[padstar]

Thanks for the help guys. Happy with isolating the rads using the valves in most instances (where the pipes drop down within the floor void) but some have the feed and return pipes surface fixed along the skirting (which I want to remove and work on). In these instances is it ok to drain the system from a drain off valve i have yet to locate then cut the surface mounted pipework back past where i need to access and cap off.

How long does a gravity fed system take to refill (8 rads on the system)

 

[Madrab]

Oh and on your first pic, the copper pipe going into the bottom will be the gas supply. The plastic coming out is the condensate.

 

[Burnerman]

You can do it that way if you need to, but sometimes gravity feed systems are prone to airlock on refilling -which will manifest in the odd cold radiator until the airlock is cleared.
John

 

[padstar]

You are asking far too many questions at the same time you will just get confused

Agreed - Sorry i will start again and slow down.

1st off, is the new mark up below correctly labelled so i understand the basic working of the cylinder?

 

[ianmcd]

Agreed - Sorry i will start again and slow down.

1st off, is the new mark up below correctly labelled so i understand the basic working of the cylinder?

View attachment 179322

yep that all looks correct

 

[Burnerman]

All good there with the possible exception of the gate valve on the right.....I’d guess that is a gravity cold feed to an outlet somewhere? Looks like 22mm, or maybe the old 3/4”.
John