New Water Cylinder in Hot Press. Advice sought.

I am having our water cylinder replaced in our hot press. I think it is called an open vented system with water coming from the tank in our attic. Our existing system is heated by a Stanley gas cooker range in our kitchen. During the summer we have an immersion heater.

We need to replace the water cylinder in our hot press.

A plumber called and suggested that we get an Indirect pre-insulated cylinder. 42" x 18" plus a new 18L expansion vessel. Cost plus VAT and supply and fit €880. Are these tanks suitable to have an immersion fitted for summer use?

Is this price about right?

We will most likely get a new bathroom installed later on this year or early next year. I assume that we will need two new pipes coming from the water cylinder to feed water to our new shower. Does the plumber create a new outlet in the tank for these new pipes or do water cylinders already come with these outlets in place? If not should I order our new tank to have these put in place now?

Finally, we will need a pump for our new shower. Is this fitted to the tank or the pipes leading to the tank and is it an easy job to put in place?

AFAIK Your tank is just one-in one-out water pipes, cold at the bottom, hot at the top. The splitting is done elsewhere. Same with the pump.

If he is draining the tank now,the best option would be too make the supply’s now with valves and end caps,it will save having too drain the tank twice
And make the new bathroom installation sumwhat easier.
Make sure the tank can handle the increase in capacity too.

Pinoy adventure said:

Make sure the tank can handle the increase in capacity too.

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We are increasing from 120L to 142L. Maybe not enough?

almostthere said:

We are increasing from 120L to 142L. Maybe not enough?

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Check the flow rate on the new shower and you’ll see if it’s ok for 142lts.

Pinoy adventure said:

Check the flow rate on the new shower and you’ll see if it’s ok for 142lts.

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Can you clarify how I do this? The shower will be put in place after the cylinder.

Here's one online shop selling the tanks at €331 and a similar expansion vessel for €53. Can take time and be a little messy to fit so pricing likely not too far off the mark.

As above, the tank itself has just a single feed in at the bottom and feed out at the very top, all other hot connections come from the pipework attached to the outlet pipe, and cold feeds may come from the pipe attached to the inlet, or directly from the tank in the attic.

almostthere said:

We will most likely get a new bathroom installed later on this year or early next year. I assume that we will need two new pipes coming from the water cylinder to feed water to our new shower.

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I presume this is re-fitting an existing room rather than building an extension? Do you have a shower in the current bathroom? If so what type is it?

Electric showers that ran from a single cold feed used to be the most common, if you are planning on switching to a pumped mixer shower you will need to add a hot feed.

almostthere said:

Can you clarify how I do this? The shower will be put in place after the cylinder.

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You need to decide on the type of shower you want, then look up the typical water usage of those, then work out how long you are likely to run the shower for typically. A good plumber will be able to advise.

Leo said:

Do you have a shower in the current bathroom? If so what type is it?

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Thanks Leo. Yes, we have an existing shower that I think is called a gravity shower. I am just wondering if leaving it as a gravity shower, without pump would suffice? Our existing shower does the job but nowhere near as nice as a shower you would get in a hotel or similar.

almostthere said:

Yes, we have an existing shower that I think is called a gravity shower.

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Do you know the make / model? Is there an isolation switch on the ceiling or wall outside?

Gravity showers have unpressurised hot and cold feeds. Adding a pump along the existing pipework usually isn't a big deal in that setup.

almostthere said:

I am having our water cylinder replaced in our hot press. I think it is called an open vented system with water coming from the tank in our attic.

Click to expand...

almostthere said:

A plumber called and suggested that we get an Indirect pre-insulated cylinder. 42" x 18" plus a new 18L expansion vessel.

Click to expand...

Leo said:

Here's one online shop selling the tanks at €331 and a similar expansion vessel for €53.

Click to expand...

The existing system is vented. Why would you need an expansion vessel unless the plumber is proposing a change to an unvented system? Replacing with a like for like vented system (with an insulated cylinder) would be simpler and cheaper.

almostthere said:

Can you clarify how I do this? The shower will be put in place after the cylinder.

Click to expand...

Have a look online for the shower your going with and read it’s instructions.the flow rate will be indicated on it.

Early Riser said:

Why would you need an expansion vessel unless the plumber is proposing a change to an unvented system?

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Good question. Unless they're switching, the pressure vessel may be to replace a failing one on the central heating circuit.

@almostthere

It sounds like an old house. I would be hesitant about changing to an unvented system in such a set up - as seems to be what the plumber is proposing. You will get better water pressure all around the house and you should be able to run a shower from an unvented system with no extra pump required. But there is a lot more water pressure in such systems. If you piping is old it may not be up to this.

Generally people who are replacing a vented system (with a tank and overflow in the attic) go with like for like, unless there is a pressing reason ,eg, needing the attic space for something else, wanting to increase water pressure around the house. There is no attic tank/space required in an unvented system but it needs an expansion vessel instead. Many newer compact houses will have such a system.

An unvented cylinder is usually more expensive as it needs to be at reinforced standard for the extra water pressure. There are extra building regulations to be complied with at installation and it is likely to be more expensive to install (probably more so as a retrofit). I am not a plumber but I believe they are supposed to be serviced/checked regularly as the compressed pressure is potentially dangerous.

Are you clear on what the plumber is proposing? If not you need to check.

There are plenty of sites outlining the basic differences in systems. This one is UK based but may help: