No header tank?

[NSBARR]

I have no header tank in my central heating system.
This is the first time I have used this forum so please bear with me. I have a two up two down Victorian terrace house with a Gloworm Ultimate Boiler. There is a 'Fortic' (indirect combination unit) style immersion cylinder with the top section being the header tank as such. It is a pumped system but with no TPD vale. All the (five) radiators are installed below the height of this cylinder. It has a very basic controller that allows either hot water of hot water & heating (will not allow heating only!). The system had to be drained down but now I can find no way of filling the system, there is no header tank in my loft and I have checked throughly - no tank and no expansion pipe. I am at a loss how this system works but it has been fine for at least the last five years, Any one know anything about such a system- help urgently needed!

 

[bathstyle]

Primatic cylinder, other will advise on what to do to refill system, I'm out the door....

 

[Goldberg]

It's probably a Primatic.

Presumably you closed a valve to stop water entering the system while you drained it, so all you need to do is open that valve again. Don't add any chemical corrosion inhibitor.

 

[NSBARR]

Ah! I think I should explain. The reason I drained the system was to replace the old cylinder. I believed I was replacing like for like as the new cylinder had exactly the same fittings and design as the old one (or so I thought). The new one is a RCM Indirect Combination (900 x 450) with an open top combined header tank. I assumed it was the same as the old Fortic F2 I replaced. Is Primatic a generic term or have I got the wrong type and shoud have gone to one marked as Primatic? Could this explain why it wont fill up the heating system. It works fine for hot water at present using the emmersion heater only. Many thanks for your comments so far.

 

[kevplumb]

primatic cylinder

View media item 15179
might help

 

[Goldberg]

Ah! I think I should explain. The reason I drained the system was to replace the old cylinder.

Good explanation

I believed I was replacing like for like as the new cylinder had exactly the same fittings and design as the old one (or so I thought).

You can't tell a Primatic from its connections.

The new one is a RCM Indirect Combination (900 x 450) with an open top combined header tank.

As you probably realised, that header tank is for the secondary water, i.e. domestic hot water. You probably have a very poor hot water flow rate from your combination cylinder.

I assumed it was the same as the old Fortic F2 I replaced. Is Primatic a generic term or have I got the wrong type and shoud have gone to one marked as Primatic?

Primatic has become a generic term, but AFAIK they're not made anymore.

Could this explain why it wont fill up the heating system.

Yes. Your choices were:-

1. Vented (or unvented) cylinder with unvented primary circuit.
2. Vented (or unvented) cylinder with vented primary circuit.

In the second case, you would/will need to install a feed and expansion cistern for the primary circuit, but if the cylinder coil will take it, you could convert the primary circuit to unvented.

 

[JohnD]

getting rid of the old primatic is no bad thing, but you will have to do some pipework and add a small Feed & Expansion tank.

Have you got a loft, and does it have a cold water main into it?

How much room is there around or above the cylinder in your aiting cupboard or wahtever?

If you can post plenty of photos showing your pipework, it will help a lot

//www.diynot.com/forums/viewtopic.php?t=129539

 

[Goldberg]

...AFAIK they're not made anymore.

I was wrong:-

http://www.heatandplumb.com/acatalog/Range_Primatic_Vented_Single_Feed_Cylinders.html

 

[NSBARR]

Can't believe how many of you have troubled to post a reply, thanks to you all.
I think the best solution would be to add an expansion tank in my loft. I have plenty of room and can easily get a mains supply up to it. I gather this should include the cold water mains to the tank, into a suitable ball valve (and include an overflow!). I'm presumning I can the run the gravity feed from this tank to the incoming C/H pipe (top) to the cylinder and run an expansion pipe from the outgoing (bottom) C/H pipe from the cylinder to rise above the new tank with a suitable bend. Should both the C/H pipes be in 22mm or can the expansion be 15mm? I guess it's OK to have the mains feed in 15mm. Please excuse any non-technical terms I'm an electrician by trade (retired).

 

[Goldberg]

...I gather this should include the cold water mains to the tank, into a suitable ball valve (and include an overflow!).

Not sure what you mean by the word "include" there, but yes you need to run a cold mains supply to the cistern, with a 1/2" float valve. And yes - you MUST fit an overflow warning pipe. This should be at least 1" below the mounting hole for the float valve. You should use a Part 2 float valve and fit the float at the extreme bottom of its range of positions, to allow for sufficient expansion of the primary water without reaching the warning pipe outlet.

I'm presumning I can the run the gravity feed from this tank to the incoming C/H pipe (top) to the cylinder..

Again, I'm not sure what you're intending there, but you should connect the feed (from the F&E cistern) into the boiler return, i.e. the pipe from the cylinder to the boiler. The vent should run from the flow, connecting to the highest point of the pipe run from the boiler to the cylinder, to a vent pipe looping over the F&E cistern. This vent pipe must constantly rise, and is best piped using 22mm copper tube.

I guess it's OK to have the mains feed in 15mm.

Yes. You should lag it to cut down on condensation which can otherwise cause degradation from dampness.

Please excuse any non-technical terms I'm an electrician by trade (retired).

Ah, that explains a lot.

 

[NSBARR]

Many thanks Goldberg. That makes it much clearer.
Plumbers! With a sense of humour, whatever next?

 

[Goldberg]

I'm not sure I like being called a plumber

 

[NSBARR]

Sorry, meant to say Kwontum Mechanik!

 

[doitall]

Sorry, meant to say Kwontum Mechanik!

Handyman would be better

 

[NSBARR]

Alright, already! Thank you handyman.

But seriously, it is so useful to be able to post to a forum like this and get such a good response, thanks to all.