AGA, Cylinder and Radiator Issue

[Jimmeh]

Hi guys, hope your all having a good evening!

Today I went to look at a job near me, lovely people.

Now they have an aga downstairs, that appears to me to be providing heat to a cylinder upstairs via a gravity feed system (believe thats the name for it) (has no pump and relys on hot water rising to the cylinder, through the coil to heat the hot water (has an immersion as back up of course!)
Now they have had a plumber come in and install a single radiator, which he has tee'd into the flow and return (just outside of the cylinder) and he has added a pump to the flow side of this pipework and he has added a full bore valve to isolate the radiator circuit if needed.
Now the customer is complaining that if they open the valve and turn on the pump that all of a sudden they get dirty hot water (brown and mucky) from their hot taps and it drains all the water from the tank (in the loft)

This would make me think that the coil is cracked in the cylinder, but wouldnt they get dirty water all of the time regardless of the pump being on, and also I was under the impression that maybe a pump is not needed as a towel rail type radiator could be used as a "heat sink" and would not need the pump?

What are your opinnions as I am a bit stumped on this one!

[stani]

are you sure its an indirect cylinder and not a primatic?

[ADM360]

With out looking at the I couldn't say for sure, is it an old install? sounds like its a direct cylinder! is there a seprate F+E tank in the loft to feed the aga side, in the airing cupboard where the 28mm gravity feeds from the aga go into the cylinder is there a cold feed and vent!! if I remember correctly when you look at the tapping for the aga feeds if there are made with male irons then it's a direct, if Female irons the indirect apart from primatics!!
which if it is a direct cylinder the aga will directly heat the water that comes out of the taps, therefore and crud will have settled over the years at the bottom of the cylinder and the gentle action of opening and closing the taps dosn't really move it but when the pump is turned on all the crud is stirred up and comes ot the taps!! also if this is the case then a rad should not have been fitted to this side of the system as no inhibitor can be added the rad will rust out in no time as it always be feed with freash oxygenated water!!

hope this is some kind of help!!

[Jimmeh]

hmm come to think of it, it did appear to be a single feed, which would make it primatic, however I have zero experience
of primatic cylinders apart from knowing they are self priming I believe!

[stani]

ADM360 got it in a nutshell pump stirs all the muck up

[Jimmeh]

deffo 28mm feeds aha so basically being a direct cylinder, there is no coil and the plumber did not realise this, whats the best option then, as I doubt they will want to change the cylinder as I am aware of the incredible heat that the agas can produce! Should I just suggest adding an electric element to the towel rail that they have and I can deal with the existing pipework?

I just realised how tired I must have been when I looked at this tonight, of course its a direct cylinder, as the aga has its own cylinder as well doesnt it... duhhh

Solutions welcome though!

[jase158]

sorry bit confused, are you saying that the pump is pushing the central heating water to mix into the tap water?

[ADM360]

If they went for the cylinder change then with in reason you could add more rads etc. but you would need to add new F+E tank to feed the aga side, and in my oppion I would recomend that they changed the cylinder it would be better all round as when water is heated the limescale drops out so all the lime is slowly filling the aga!! and as the aga will probably be cast fresh water will sped up its faliure, so an upgrade will improve everything!! you can say that the brown water is always there to some degree or another and a change would remove that!!

again hopes this is of some help!!

[ADM360]

sorry bit confused, are you saying that the pump is pushing the central heating water to mix into the tap water?

not excatly, but in an older direct system there are one and the same, the cold feed enters the cylinder out though aga return back up the flow into the clynder and on out the the hot taps!!

[jase158]

oh ok, so no radiators then?

[ADM360]

oh ok, so no radiators then?

no not really, and you don't want to put to much lagging on the cyliner either if its an older aga as this could end up boiling the cylinder!!

[Best]

An Aga is supposed to be joined to an unlagged cylinder. It can be joined directly, as this seems to be, but could be joined indirectly using a exp/feed tank. Aga didn't recommend a rad joined to them, but a small towel rail should be the most you use & on a gravity link only. No pump anywhere or valves should, or need to be on the pipes to cyl. Obviously if it stays on a direct cyl, then a rad would have to be brass or copper.

[Jimmeh]

so i could in principle, remove the pump and replace the towelrail with a brass towel rail ? would that work?

[stani]

you would probably get mugged carrying a copper radiator before you got it to your van. lol

[Best]

Yes, you should be able to put a towel rail to the pipework but remember ordinary towel rails are made of steel, so no good on direct Agas. Link from flow, falling into a top connection of rail & drop from a bottom connection to return. Easy if rail is on wall of hot press. I would prefer indirect way, with an ordinary standard cheaper rail.