Replacement Copper Cylinder Advice

Myles45

Hi,

Have just sprung a small leak in the very bottom of our 9 year old copper indirect cylinder (unlagged). It's 1050mm x 450mm.
We have well water which has only had a softener put on it about 2 months ago. The leak suddenly appeared after the tank had been fully drained & then refilled (Had run taps to drain cold water from attic tank for other reasons, but father had also drained hot water!!) Obviously this didn't cause the leak but I think it may have perhaps dislodged some sludge that may have been blocking the hole.
Anyway, the upshot is we're going to need a replacement now & I'd quite like to upgrade it if possible without too much additional cost. It's for family of 4 & we can run short of hot water & it does cool down fairly quickly as it only has one of those crappy red jackets. I have lagged the pipes around it but don't think that helps much.
Water is heated & pumped by oil boiler. Not sure if any more info is needed for advice.
I gather stainless is not good for well water with softeners & to be honest I think it would be too costly. I'm thinking maybe a slightly bigger pre lagged tank but open to advice.

Thanks

Myles45

OK I thought I'd fixed it with a good lash of silicone & some epoxy resin but sadly it's leaking again. I've been looking around on the internet for a replacement but more confused by the options & not really sure of the differences. Anyone have any knowledge on this please?

What's difference between grade 2 & 3 copper? Standard & rapid option & single or twin coil cylinders?

trobbin

Hi. It's hard to determine exactly how the cylinder began leaking, but I wouldn't worry too much about your fresh water source, copper is very good with fresh water. It was more likely sludge or if the cylinder was sitting on a piece of metal like a nail, it will cause a corrosive reaction called electrolysis.

For replacing. Consider the size of your current cylinder if that doesn't provide enough hot water, get a bigger one, if you've got the room. Always get an insulated cylinder, saves money. You only need a single coil cylinder as you've only one boiler, ie. one return and flow. Twin coils are for homes with an extra heat source, ie. wood burner, solar, ect. I'm also not sure on the grades, but you just need a standard.

Hope that helps in some way.

donedl1

http://www.grantengineering.ie/wp-content/uploads/2011/04/grant-cylinder-brochure.pdf.

This would be a good place to start. The better the insulation the longer the hot water will last.

7ofBrian

AFAIK the grades refers to the thickness of the copper sheet used to make the cylinder.

Myles45

Thanks. ok I think i have it now. Hursts in Castlebar do them. Insulated single coil, just have to hope it will hold out over night now.

Dtp1979

Myles45 wrote: »

Thanks. ok I think i have it now. Hursts in Castlebar do them. Insulated single coil, just have to hope it will hold out over night now.

I'd go with a dual coil cylinder. Join the coils and your water will heat much quicker than before

Myles45

Dtp1979 wrote: »

I'd go with a dual coil cylinder. Join the coils and your water will heat much quicker than before

I think they actually do a rapid recovery version which I think has a bigger coil area to do the same as that. Although your idea may work out cheaper I suspect, but would also give us the option to add solar in future if we wanted?

Dtp1979

Myles45 wrote: »

I think they actually do a rapid recovery version which I think has a bigger coil area to do the same as that. Although your idea may work out cheaper I suspect, but would also give us the option to add solar in future if we wanted?

Of your thinking of solar then buy the one with solar coil. Link the oil into that and whenever you get solar just disconnect the oil from the solar coil

shane0007

Downside of using both coils is it will take a lot from the heating side, especially if the system is not fully zoned.

Myles45

shane0007 wrote: »

Downside of using both coils is it will take a lot from the heating side, especially if the system is not fully zoned.

So would you say then that really we would be better off getting the rapid recovery cylinder in that case?

I don't know if you would say we had a fully zoned system. it's pretty basic in that we have two switched valves which open or shut the heating separately for upstairs & downstairs & the hot water tank branches off from the feed before the valves so if boiler comes on then it always heats water.

I don't in reality envisage actually getting solar for a good few years if ever so don't think we'd really need a second coil.

I did however think that the rapid recovery would potentially save money in the summer when we are only heating water as I presume we would be using less oil if the tank heats quicker?

shane0007

Rapid recovery coil cylinders are excellent if they are what they say on the tin.
Many call themselves that but are far from it. Some are just an extra length of 3/4" copper pipe coiled, a bit longer than what they usually are.
In my opinion, a rapid recovery coil is a finned coil so that the actual surface area of the coil is significantly increased to increase the water temperature quicker. All cylinders should also be issued with tested data sheets.
I would also give consideration to stainless steel cylinders if you are mains fed. Even if you are not mains fed, I would consider them. Stainless steel cylinders retain water temperature far better than copper cylinders. Copper is a very good conductor of heat & therefore transfers a lot of water heat into itself, whereas stainless steel is not. Typically over a 24 hour period, a copper cylinder will loose approx 30C, whereas a similar stainless steel cylinder over the same time period would only loose approx 5C. So you are signicantly saving on DHW heating costs & recovery times are greatly reduced.

shane0007

Precision Heating do the Gledhill Envirofoam stainless steel cylinder, sized as copper sizes. I haven't used the a s yet but I hear good reports back on them. They are made by Gledhill.

http://www.gledhill.net/page/91/EnviroFoam-Stainless.htm
http://www.gledhill.net/pdf/Spec%20107-06%20EnviroFoam%20Stainless.pdf

Myles45

shane0007 wrote: »

Precision Heating do the Gledhill Envirofoam stainless steel cylinder, sized as copper sizes. I haven't used the a s yet but I hear good reports back on them. They are made by Gledhill.

http://www.gledhill.net/page/91/EnviroFoam-Stainless.htm
http://www.gledhill.net/pdf/Spec%20107-06%20EnviroFoam%20Stainless.pdf

Interesting Shane. But just read the brochure there & it states only suitable for pumped systems. Ours is gravity fed, so presume it wouldn't work?

Also we are on our own well with recent softner & filter fitted which I've heard isn't good with stainless tanks?

Myles45

Called Precision today & apparently they are suitable for use on open vented system.. Happy Days
Just have to clarify manufacturers specs for well water quality as apparently they will void warranty if tank fails & a water test shows certain undesirable elements. Can cross reference with recent water test & if all ok then I think this is the way to go.

shane0007

Myles45 wrote: »

Called Precision today & apparently they are suitable for use on open vented system.. Happy Days
Just have to clarify manufacturers specs for well water quality as apparently they will void warranty if tank fails & a water test shows certain undesirable elements. Can cross reference with recent water test & if all ok then I think this is the way to go.

Yes, all unvented cylinders are suitable for vented installations.
You may not be able to test for what fails a s/s cylinder as they generally fail due to the low oxygen levels in well water. Mains water goes through treatment systems which due to the process naturally re-oxygenates itself.
Well water, sitting below ground has much lower levels of oxygen & this low oxygen level water can react with the stainless causing corrosion & failure.
It is this the manufacturers will not hold up a warranty & it is difficult to test for.

There are other minerals, etc. in well water that can corrode your cylinder but these can be tested for & treated.

Low oxygenated water is not very common but you should be aware of the warranty implications.
I have a stainless cylinder in my own home with no issues from my well.

Myles45

Strange anomaly that really, being that it's normally oxidization that causes rust in metal. So you would think that less oxygen in the water would be better!!

I'm also presuming that whatever reaction that takes place to corrode a stainless tank would do the same or worse to a copper tank, no? & the fact that the price of the stainless tanks are relatively similar to copper I would be better going with the stainless do you think?

I think I read somewhere that some of the stainless tanks are glass lined, but I would imagine they would be rather more expensive.

jack of all

shane0007 wrote: »

Rapid recovery coil cylinders are excellent if they are what they say on the tin.
Many call themselves that but are far from it. Some are just an extra length of 3/4" copper pipe coiled, a bit longer than what they usually are.
In my opinion, a rapid recovery coil is a finned coil so that the actual surface area of the coil is significantly increased to increase the water temperature quicker.

+1 on the above; I replaced a rapid recovery cylinder in my own house last year (it was a true rapid recovery cylinder with finned coils) as it had developed a leak in the coil. I ordered a replacement, made to order, to minimize modifications to the existing pipe connections in a tight hotpress space. The cylinder was stamped and labelled rapid recovery but the coils were not finned, just longer than a standard coil. What could I do, 4 days without hot water and no heating, I fitted it anyway but I wasn't happy about it!

Myles45

jack of all wrote: »

+1 on the above; I replaced a rapid recovery cylinder in my own house last year (it was a true rapid recovery cylinder with finned coils) as it had developed a leak in the coil. I ordered a replacement, made to order, to minimize modifications to the existing pipe connections in a tight hotpress space. The cylinder was stamped and labelled rapid recovery but the coils were not finned, just longer than a standard coil. What could I do, 4 days without hot water and no heating, I fitted it anyway but I wasn't happy about it!

So have you noticed a big difference in the ability of it to heat quickly then compared to your old one? & if so what sort of a difference would you estimate?

jack of all

Myles45 wrote: »

So have you noticed a big difference in the ability of it to heat quickly then compared to your old one? & if so what sort of a difference would you estimate?

It's really hard to gauge, I am happy enough with the new cylinder's performance and it heats up quickly enough for our household as we use a lot of hot water (2 adults, 3 children). I did go for a grade 2 cylinder in the expectation that I should get a longer life from it. When I looked at the old finned coil I couldn't figure out how it is manufactured (some sort of extrusion process?) but I wonder if the finned coil is inherently more prone to failure as a result (there was a lot of scale build up on the fins as the system was installed and operating for a few years before I retrofitted a reverse osmosis water softener).

Irish Steve

I know it needs an extra pump to make them work, but I can't understand why the number of heat exchangers isn't higher.

Small unit external to the cylinder, no internal coil needed or used, the second pump takes cold water from the bottom of the tank, and pumps it through the heat exchanger, and hot water then goes into the top of the tank. Recovery is very fast, and the real advantage is that if it's the right size, and set up correctly, it's single pass, so the hot water is HOT within minutes. So, when we go away for a few days, and come home, fire the boiler, there is HOT water, (not much initially of course) on the top of the tank within 5 minutes. thermostat on the lower part of the tank turns the pump (and zone valve etc if appropriate) off when the tank is up to temperature.

If there's a LOT of hardness in the water, it can cause problems, but there are ways around that without too much work. Had ours for 20 years now, and wouldn't go back to internal coils unless I was forced to. It's also a way to use an internal coil for solar, and then have a way to use the "old" oil, gas or solid fuel system without having a second coil.

All I need now is a cheaper cost per Kw fuel source, but that seems to be a low priority to our wonderful leaders, they need the massive taxes associated with coal, and oil.