To combi boiler or not ?

sherlock · 24 Sep 2006

We live in a victorian apartment building in which there are 9 flats. We live on the top floor.

I have a gravity fed gas central heating system.
Our boiler is an ideal elan 2
The cylinder is a hercal coil indirect cylinder and the sticker on it says 1984.

For some time now I have noticed that when I try to run a bath, brown things almost like bits of algae come out in the hot water. This does not always happen, but it does happen very frequently.

The tank in the attic (a large wooden lead lined one has been looked at and is clean) Thus the problem must be coming from the cylinder.

A plumber advised me to run the hot water for hours to try to clean it out. I did this a few weeks ago and ran the water until it actually stopped running at all. This took about 2.5 hours. Initially there was great improvement, but after about a week the problem came back.

We are also having a problem with the rads. They are hot at the top, but not at the bottom. Sludge? related to the algae problem? We have 7 rads. They are westherm. The bore of the pipes to and from the rads is quite thin, about as thin as a thin womans wedding ring finger. (not very scientific I know!) I feel that the people who lived here before us may have installed these rads themselves.

I had a plumber round a week ago who suggested getting a combi boiler? It is my understanding that a combi boiler takes water directly from the mains and that also it may not be suitable for all systems. What would you advise in this case? Should a combi solve the problems?

pannierstan · 24 Sep 2006

You need to check 2 things before deciding on a combi and they are the standing pressure of your mains water up at the top of those appartments and also the flow rate of the cold water.

There is no point having a combi if these two are inadequate and the plumber should have checked them before he even mentioned it.

Your system is difficult to cast judgement on but generally if the rads are less than 20 years old, the water in the system is good and the rad valves are a resonable make then the system should cope with a combi.Again a good plumber

will be able to make these judgements for you

stan

sherlock · 24 Sep 2006

Water pressure used to be terrific here, but lately we in the building have all noticed that the pressure has got much lower, Scottish water of course deny this, so I'm not sure about that.

Do you have any view on the algae? Could we just not change the cylinder in the kitchen? Is that an easy job?

Agile · 24 Sep 2006

Although the cylinder is presumable very old like your boiler it should not be necessary to replace it just because of the algae.

I am guessing that the algae occur because the roof cistern is too big and the chlorine is evaporating and your hot water is not adequately dosed to kill the algae. Some of them are pretty impervious to algae.

My suggestion is to add a bottle of domestic beach to your cylinder and leave it for a few hours. Perhaps get it in through an opened compression pipe connection.

If there are only a few people fed by the cistern then perhaps add a bottle of bleach to the cistern twice a day for a few days and warn others to be aware of the extra chlorine in the water.

Tony

doitall · 24 Sep 2006

Bleach in a domestic cylinder, you must be mad

Get it chlorinated properly. although I suspect that maybe the cylinder coil has gone, which could also account for the sludge build up.

sherlock · 24 Sep 2006

Hi Tony.
Are you suggesting that I put the bleach into the hercal cylinder in my kitchen? I don't have the foggiest how to do that. I would need to get a plumber to do it, which I don't mind at all. However The plumbers who have seen the algae type substance have all seemed at a complete loss to identify it and have acted as though this is a problem that they have never come across before. Incidentally, do you think we are in any danger health wise from this stuff?

do you have any opinion on the radiator problem. i.e the rads being hot at the top and not the bottom

sherlock · 24 Sep 2006

hi doitall. I've just seen your post. How do I go about chlorinating properly? Is this a job for a plumber? Also, you seem to think I should be replacing the cylinder. What about the boiler too?

doitall · 24 Sep 2006

sherlock said:
hi doitall. I've just seen your post. How do I go about chlorinating properly? Is this a job for a plumber? Also, you seem to think I should be replacing the cylinder. What about the boiler too?

The cylinder would need to be checked by a plumber to verify the coil is good or gone

Chlorinating is done by a dedicated Company (water pure) do all ours, have a look in your local directory.

The Elan is a very good boiler but not very efficient, and as it's getting on a bit, it would pay you to replace it.

As for a combi it all depends on the mains supply and pressure, I would look at system boilers with a new cylinder.

Is the storage tank a communial one or just for your flat.

sherlock · 24 Sep 2006

The tank in the attic is for everyone in the building. I believe there should be a header tank for our flat, but I have not been able to see it in the attic and I have been up there loads of times now. It may be above the cylinder in the cupboard in the kitchen but since everything is very snugly fitting I can't see above the cylinder.

sherlock · 24 Sep 2006

Actually, I have just got a torch and had a good look in the cupboard and there is no tank above the cylinder, but just pipes leading to the attic and presumably to the big tank where the water is.

doitall · 24 Sep 2006

In that case look around the cylinder for the words "Primatic"

will be near the top of the straight section around the area where the primary pipe connect.

sherlock · 24 Sep 2006

Cannot see the word primatic anywhere. The sticker just says coil indirect cylinder .

doitall · 24 Sep 2006

Ok follow the pipes that connect to the side of the cylinder and run up, maybe into the loft, there should be a small tank on the end somewhere.

Can you post a pic of the cylinder showing the connections.

sherlock · 24 Sep 2006

Cannot go into attic to find small tank as it is a two person job. Very high ladder required to get into attic and need someone at bottom to hold. Attic hatch is about 15 feet high up.
Also , have no scanner at the moment so cannot post pic unfortunately.

gasdave · 24 Sep 2006

Yes quite right, wait for help.

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To combi boiler or not ?

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