Barking up the wrong Gravity Coil?!

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Hi All,
In a previous post I asked if anyone could help to identify a combination tank that is connected to the solid fuel Rayburn No.2 in a property I just purchased.
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The consensus was that it was a Direct Fortic, possibly Primatic. There is no F&E tank anywhere so not sure whether it is or isn't.

I trotted along to my local Plumb Centre and explained that I wanted to replace the DHW system with a separate well lagged cylinder with provision for an immersion and a CWT. The gent recommended a Gledhill, and to be sure of what he was selling rang Gledhill Tech to confirm. They said an Indirect Gravity coil with 1 inch tappings was the boy, so I purchased accordingly, along with a polytank CWT sized to fit into the airing cupboard I was building.

Now the kicker, and the leading question! Having now removed the old cystern, the label on the back (typically!) identifies it as a Gledhill Direct Combi to be used with secondary system only. It has a coil with 1 inch tappings at 15 inch centres and an immersion fitted.

The million dollar question(s)..

How did the original coil get maintained if no F&E is present, and what stopped it going 'Bang' if it was sealed between the Rayburn and the cylinder?

Does my new setup need a F&E tank or should I just reconnect the cylinder to the flow and return pipes to the Rayburn, and if so how are they filled waterwise?

I rang the company that did the original tank install as the owners son was at school with me, but they were vague to say the least.

Your advice, as always, is very much appreciated.

Regards, Nick.
 
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I'm sure it's a primatic that you've taken out they are just called direct combination cylinders because both CH/HW are fed direct from the one single tank.
Confusing this plumbing game in-it?
 
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And Gledhill charge 60p a minute to to talk to their technical line, which is why I never phone them, so dont tend to use their products.
 
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You`re talking to the wrong people :LOL: Try Rayburn :idea: You don`t say if there are any rads - maybe you do in a previous post - But rayburns can be connected to a direct cylinder - combination or otherwise . There could be 1 cast iron rad on the primaries to the cylinder . That is quite a common setup .Also with a solid fuel Rayburn , a non - lagged cyl. is ( in my opinion) a good idea - Those B`guers boil the water - solid fuel isn`t controllable like gas
 
M

mysteryman

It could be either a direct cyl, perfectly normal if connected to a Rayburn with no rads, or it could be a Fortic Primatic.

Examine the heating connections on the old cylinder. If they go straight into the tank, it is a direct cyl. If not, put your hand across one to block it, and blow into the other. If you can't blow into without pressure building up, it is an indirect, which seems unlikely in this case. If you can blow into it continuously and it clearly has a coil or other heat exchanger, then it is a Fortic Primatic.

In this case, you may need a feed and expansion tank for your updated installation. Ask Gledhill - perhaps on a website?
 
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Fitting a Foamed Cylinder to a Solid Fuel Rayburn can cause serious overheating problems, due to insufficient heat loss- also I am not aware that FORTIC ever made a Primatic Cylinder so I am pretty sure yours would have been direct the Rayburn will have a GLASS LINED boiler, for use on Direct water supply one way to find out if your new gled hill is indirect or direct would be to try and fill it outside before connecting, if water comesout of lower coil connrection, then I think you can be pretty sure that it also is direct ;)
 
M

mysteryman

There were Fortic Primatics available, and you could fit Rayburns and the like in hard water areas without glass lined boilers. The limescale protected the boiler - which had to be descaled every now and then with sulphuric acid.

Quote to me, as a small boy at the time: "It's not hot if you stick a thermometer in it, but it's hot if you stick your finger in it!"

If you are connecting a new cyl plus radiators, you are going to need an indirect cyl plus feed and expansion tank, so go for it. Leave at least one radiator on gravity and lockshields, to protect against overheating.
 
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Its often overlooked that an F&E tank on a solid fuel system should NOT be plastic !

Normally galv iron although I would expect a fibreflass one would probably be able to withstand boiling water.

Its also often a good policy to have a bathroom rad on the gravity circuit to act as a heat dump if it all gets too hot. In the ideal world the gravity connection to the cylinder should be temperature controlled with a Cytrol valve!

Tony
 
G

Goldspoon

Its often overlooked that an F&E tank on a solid fuel system should NOT be plastic !


Tony

Can you point me in the direction of any regulation? I believe plastic, if WRAS approved F&E tank, can withstand boiling water for a minimum 500 hours...
 
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Thank you all for your replies so far, and apologies for not replying sooner, couldn't find lead for my camera and wanted to post more pics.

Nige F, you kindly replied to my last thread about this tank, and to recap, there is no heating from this setup at all, although you did advise on fitting a heat dump rad in the bathroom which would be a great idea. My concerns in this area is trying to tap into the return pipe work and running a feed to the rad without it looking a dogs dinner. As the flow and return from the rayburn emerge at waist height and run across the kitchen wall into the bathroom next to it, is it possible to drop to floor level to the rad and back up to waist level for the return? Also what diameter tube as the F&R are in 28mm?

Also, I appreciate what you're saying about an unlagged cylinder and would agree were it not for the fact that I will at a push only be using the Rayburn in the coldest months as there is no heating in the house and was hoping the heat would go somewhere to providing some background heat, with hot water being an added bonus. At all other times I was intending to use the immersion for an hour a day which is why I wanted a well lagged tank.

The combi tank is a Gledhill now that I've removed it
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Mysteryman, i tried blowing down it as you suggested, but couldn't get a note out of it!!! I did however notice that I could see out the other side of the tank when looking through the top 'Flow' tapping so think it's a Direct as you and others state. Assumably then all hot water in the cylinder passed through the Rayburn boiler which is why there is no F&E tank?
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It's looking likely then that I'm going to need a F&E tank, but not sure if I can shoehorn one into the airing cupbaord I'm building. The bathroom has a sloped ceiling and is so small you have to go outside to change your mind!! I was going to see if I could get a 4Gall poly tank in, but the size of the tank isnt so much the problem as the height of the expansion pipe I'd have to allow. It's looking more and more likely therefore that I'm going to decommision the boiler with sand and run the tank by immersion, unless any of you guys can think of an alternative?

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Cylinder is already at waist height to preserve no dip in the Flow pipe.

Thank you all again for your replies.
 
M

mysteryman

I not sure if Gledhill mean a Primatic type cylinder or a Fortic type by 'Direct combination', although I think it is the latter.

The Primatic type will be a cylinder as described in various posts above.

A Fortic type will have it's own header tank on top, like your old cyl, but this will be a direct cylinder, meaning it has not got a heat exchanger within.

If it is this direct Fortic type, which I think it is, you can't connect a steel radiator to the layout, and you won't need a cold feed tank. You can fit a non-ferrous [brass or copper] towel rail.

If on the other hand, it is a Primatic type - which is what I understood you wanted, you will need a cold feed tank for the domestic hot water supply into the cyl.

You could in this case add a steel radiator.

Either way, for the rad or towel rail, bring your return from the cylinder along under the rad or towel rail, and branch both ends of it into that return pipe. The return can then rise up into the Rayburn return connection. The main 28mm circulation pipes should NOT be lagged for this sort of job. This I am sure will work well. Just promise you won't sue if it doesn't!

By the way, a Rayburn number 2 is quite a rare beast, dating from the early 1950s. They introduced No 1 and No 2 models - one and two oven respectively, but the No 2 was revamped into No 3 almost at once, and this continued, I think, until it became the Royal series in the 1960s. Please let me know if I am wrong about this.

Rayburns and Agas are still made in this town, which is also home to two different boiler manufacturers' UK headquarters.
 

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