High Spec Shower / Wet Room

[notnormal]

Hi there,

1st post and a DIY numpty so please play nice! I'm at the planning stages of a major extension and refurb to my house. I was to install an en-suite shower room or wet room, not made the decision yet. Either way I want the shower to be a MONSTER, I'm talking warm fire hose!!! My main bathroom has a 10.8kw electric shower which does the job but isn't as powerful as I'd like.

My boiler is a Combi which is down in the garage a good distance from where the shower will be located and is only good for up to 11.4 litres per minute so I don't think that will do the job either. Also the mains water pressure where I am isn't great (no means of measuring it).

Any suggestions as to what my options are? I'm looking for a really powerful shower and maybe bodyjets as well. I was thinking of having a second boiler just to heat the shower water, is this feasible? Either a combi in the loft closer to the shower itself or is it an option to get a 'system boiler' with a pumped power shower? I appreciate there isn't going to be a cheap option but I think two boilers might be cheaper then replacing my combi with a regular boiler and the required tanks and using a power shower on that system.

Thanks in Advance

 

[electronicsuk]

If you have poor flow rate and/or dynamic pressure on your incoming supply then you will be unable to get a good shower from an unvented cylinder without either upgrading the incoming mains or fitting an accumulator.

A combi boiler will suffer the exact same problems with your lack of flow/pressure. Even if you were to provide more water, a large domestic combi is unlikely to provide enough water to run a drencher shower with body jets, especially in this weather when the incoming water is so cold.

The cheapest option is likely to be a vented cylinder with a good quality pump and decent size pipework. You could enquire about increasing the size of your incoming main, but in some areas there is still no guarantee that you will see a massive improvement if the pressure in your area is unusually low.

 

[notnormal]

Thanks for the reply. A bit of it went over my head though! Sorry to be slow but can you explain what a vented cylinder and pump would actually entail to be fitted.

Please excuse my lack or the right terminology but would the above be:

Two water tanks in the loft one hot and one cold but that fill like a cistern using the existing combi to provide the hot water to the hot tank. Both these tanks would be 'vented' so not a sealed system and not directly connected to the mains water as they refill from it like a cistern. I could then connect a powerful shower pump to both tanks and use a power mixer shower for my bathroom. As the pump is not directly linked to the main water system it doesn't matter that I have a combi?

Am I getting closer in my understanding? What size tanks in the loft would I need to allow maybe 30 minutes of showering before running out of hot water as I'm sure the shower would empty it quicker than the combi could fill it?

 

[electronicsuk]

Please excuse my lack or the right terminology but would the above be:

Two water tanks in the loft one hot and one cold but that fill like a cistern using the existing combi to provide the hot water to the hot tank. Both these tanks would be 'vented' so not a sealed system and not directly connected to the mains water as they refill from it like a cistern.

You would need a cold water storage tank in the loft, which would then feed into the bottom of an indirect vented cylinder. The cylinder contains an indirect coil which would be connected (through a zone valve, cylinder stat and timer/programmer) to the heating circuit, allowing the boiler to heat the tank. You could also fit an electric immersion heater as a backup heat source if you wish.

In addition to the cylinder feed, another pipe would be taken from the cold water storage tank to one side of a twin impeller pump, a quality brand such as Stuart Turner would be a good choice. The other impeller would be fed with hot water from the top of the cylinder. The output from the pump would feed your shower.

You could keep your existing combi and continue to use it to supply hot water to kitchen and bathroom taps if you wish, or take all hot water from the cylinder if that is what you would prefer.

I could then connect a powerful shower pump to both tanks and use a power mixer shower for my bathroom. As the pump is not directly linked to the main water system it doesn't matter that I have a combi?

Correct, as you are pumping stored water from the cold water tank, not mains water.

Am I getting closer in my understanding? What size tanks in the loft would I need to allow maybe 30 minutes of showering before running out of hot water as I'm sure the shower would empty it quicker than the combi could fill it?

Again, it would depend on the flow rate of your incoming main. A worst-case estimate would suggest that twice the capacity of the hot water cylinder would be a good start. You may have a problem finding an indirect vented cylinder large enough to provide 30 minutes of showering, though...

 

[notnormal]

Thanks for that, I'm off to research indirect vented cylinders!

 

[notnormal]

Sorry for a further question but what sort of ball park figure should I be working on for litres per minute to calculate the size of cylinder needed? ie 20 l/min would need a 400 litre cylinder for 20 minutes of showering.

 

[electronicsuk]

Sorry for a further question but what sort of ball park figure should I be working on for litres per minute to calculate the size of cylinder needed? ie 20 l/min would need a 400 litre cylinder for 20 minutes of showering.

Presumably you don't shower at 65 degrees C, so will be mixing hot and cold water, reducing the HW demand. Exactly how much hot vs cold you'll require depends on how hot you plan to shower!

Unfortunately I think you may struggle finding a large enough vented cylinder, but do let us know how you get on.

 

[notnormal]

Ahhh yes 65 degree showers would be a little on the warm side. The largest I've found with a quick search is 300L which to be honest would probably do the trick. Say 75% hot mixed with 25% cold at 20 litres per minute would give me the 20 minutes of shower time. Also the combi would kick in as soon as the cylinder started refilling from the cold tank and whilst not keeping pace with the 20L per minute output would manage to extend the time slightly. The wife can always have a cold shower!

I definitely need to do some working out the figures as to buy and install and then find it only gives a few minutes of shower time would not be good. Thanks again for the advice.

 

[muggles]

It's going to get expensive, that's for sure, a pump for the kind of shower you describe is not going to be cheap.

 

[notnormal]

It's going to get expensive, that's for sure, a pump for the kind of shower you describe is not going to be cheap.

You're not wrong! Early research is looking at around £400 for the pump!!!! Up to £800ish for the cylinder and £150 for a 455 litre cold water tank and thats before a shower itself and fitting etc. Like I said I'm at the planning stage of a major refurb and an amazing shower and wood burning stove (for downstairs obviously) are two things I've always wanted and will sacrifice other things to get!!!

 

[muggles]

Should be able to get a cheaper vented cylinder than that, depending of course on how big you're thinking! As you're going to be pumping on high demand, look at the Albion SuperDuty range, they have much better heat recovery times and should therefore keep up with your shower pump.

The pump(s) could well be the main expense, depending on just how powerful you want you may need two, if you really do want knock-you-over kind of power from your shower a pair of ST Monsoon Extra 4.5s would be the way to go http://www.buyaparcel.com/pageview.php?page=show_product&ecommerce_stockcode=46326