Pressurised cylinder

Dopey

I read on a solar panel provider's web site that they can install a pressurised hot water cylinder. Does this mean that you get better water pressure? I have a Triton electric shower that is tank fed because the water pressure from the mains supply is not good.

If I were to opt for a pressurized cylinder would this allow me to replace the power shower?

djpbarry

Moved from Green Issues.

Cheeble

Sounds dangerous:

http://www.youtube.com/watch?v=rGWmONHipVo

Perhaps they mean a pumped hot water system?

Cheeble-eers

Dopey

Cheeble wrote: »

Sounds dangerous:

http://www.youtube.com/watch?v=rGWmONHipVo

Perhaps they mean a pumped hot water system?

Cheeble-eers

That's exactly what I'm looking for.

RVR

Although spectacular, I'm not sure this video is a very relevant piece of advice?!?

I watched the episode above and they did everything they could to make the above happen. They removed all safety valves and then increased the pressure to over 23 bar before this happened. A typical pressurised DHW system would rarely be above 2.5 to 3 bar.

In fact this system is used a lot in modern houses. It is called a sealed or unvented system. You can simply pressurise the incoming cold water using a pump before it ever gets to the taps, boiler or showers.

This means it has good pressure at outlets but it does mean you need a tank and pipework capable of handling the ~3 bar that these systems operate at. There are also safety devices (valves etc) and pressure vessels that must be fitted.

Hope this helps - the exploding tank is spectacular but the reality is a lot more straightforward!!!

Dopey

Thanks for the response RVR. I take it then that it may require re-plumbing work. We have a 6 bar water pump servicing the shower in the attic room but I don't know if the pipes would be up to it in the rest of the house. The house is 50 years old.

I hate the noise from the electric shower. It wakes up the whole house. Would the system you mentioned be quiet or also have a loud pump?.

RVR

Dopey wrote: »

may require re-plumbing work...I don't know if the pipes would be up to it in the rest of the house. The house is 50 years old.

You are most likely right - the pipes in this case may have to be replaced, so it may not be feasible to do!

Dopey wrote: »

I hate the noise from the electric shower. It wakes up the whole house. Would the system you mentioned be quiet or also have a loud pump?.

You can put in a cold water tank (e.g. black tank in attic, like now) with a sumbersible pump in it. The submersible pump would be as it sounds, inside the water. This deadens any noise and gives a very quiet system.

--

Unfortunately it might be more work than it's worth to refit your older house (e.g. piping might not take it), especially given the times we're in!!!!

Cheeble

Yes, but I though the link was worth it anyway .

IME sealed (unvented) systems are commonplace for central heating, not for DHW. That's why I suggested perhaps they mean a pumped system.

The danger with sealed systems isn't the pressure, it's the temperature (ok, I know, the two aren't unrelated).

A cold water pressurised system might burst with a bang, but it won't explode like the video.

In a hot water pressurised system, the temperature can exceed 100C (water under pressure has a higher bp). When the pressure is released e.g. by a leak, or turning on a tap, the entire contents of the system instantly boil, hence the explosive effect.

You don't need very high pressures to cause this effect, 2 or 3 bar is plenty high enough if you have a large volume of water and heat it to a high enough temperature.

Cheeble-eers

quentingargan

Just coming back to Dopey's original question, I am sure that what they meant on the website by "pressurised" is simply that your mains pressure is used throughout your hot water system.

This is quite commonly done and as RVR pointed out, there are multiple safety systems to prevent exploding cylinder and for very good reason as shown in that video. Most one-off houses with dormers etc., have this system as if there is no proper loft, then there is nowhere to put an attic tank and no other way of getting pressure into an upstairs bathroom.

I just wondered if Dopey has poor mains pressure in the only tap which is usually fed directly by the mains - the kitchen cold water tap. All other taps in the system would be fed by the attic tank, including any showers.

Dopey

quentingargan wrote: »

I just wondered if Dopey has poor mains pressure in the only tap which is usually fed directly by the mains - the kitchen cold water tap. All other taps in the system would be fed by the attic tank, including any showers.

Thanks for the response quentingargan. That's correct. The water pressure through the kitchen tap from the mains is very poor. We also have mains supply to the toilet in the attic conversion to avoid the pump starting every flush. It's slow to fill but works fine. I don't think it's sufficient supply to mix with very hot water from a cylinder.

If I go for a solar panel system I guess I'll still have to have a consider a pumped shower for the bathroom on the same level as the hot water cylinder. The attic shower will also still need the pump because it's located above the level of the hot water cylinder.

KAGY

Dopey wrote: »

Thanks for the response RVR. I take it then that it may require re-plumbing work. We have a 6 bar water pump servicing the shower in the attic room but I don't know if the pipes would be up to it in the rest of the house. The house is 50 years old.

I hate the noise from the electric shower. It wakes up the whole house. Would the system you mentioned be quiet or also have a loud pump?.

I have such a system and all the pipe work have brazed connections, you would have to eliminate all dribbly taps etc. because the pump is pressure controlled, all it takes is a few drips and the pump turns on for 15 seconds to bring the pressure back up. As far as noise is concerned there is some, we have the pump outside in a boiler house attached to the house and you can hear it if you are on that side of the house, but now it's one of those back ground noises, no louder than any central heating noise.

Joey the lips

Its worth bearing in mind that going from the irish antiquated system to a pressurised system is not the holy grail in all cases. There can be problems initially with leaking pipes etc just while you are getting the system right.

Having said that at a cost ESTIMATED to be around 6k for the adverage house. It is worth every penny. In fact I will stick my nose out and say it has more seen advantages than solar.

1. There is no need for electric showers of any type meaning you can have a lovely brass chrome valve

2. The heathing time for pressurised water is quicker and lasts longer when heated

A slant on the pressurised system is to have a dual coil pressurised solar cylinder installed if your thinking of pressurising giveing you the option of looking at solar later which your heart and budget recovers.

rodred

i am just about to start a system like this, i want to put the
solar cylinder and tank in the attic, pressurized system.
my plumber suggested to build a small boiler house on the side
of the house for the cylinder and tank with the pump etc.
can anyone tell me if this is advisable?
he said the noise form the pump could be very annoying,
house is 1200sqft.
any info much appreciated

One of the issues with a lowish pressure is poor flowrate, it makes the shower a bit of a dribble. Where we live also has a poor flow, so I have installed a cold water accumulator.
It's a tank with a rubber diaphragm that fills up with water while all the taps in the house are off and empties when a tap is turned, the flow is much improved.

quentingargan

rodred wrote: »

i am just about to start a system like this, i want to put the
solar cylinder and tank in the attic, pressurized system.
my plumber suggested to build a small boiler house on the side
of the house for the cylinder and tank with the pump etc.
can anyone tell me if this is advisable?
he said the noise form the pump could be very annoying,
house is 1200sqft.
any info much appreciated

A long pipe run from the panel to the cylinder causes huge heat loss in the solar water heating system - it is always best to keep that pipe run as short as possible. I would have thought that would be a lot better to locate and isolate the pump in such a way that it doesn't transmit noise.

Also, it depends on where you could locate such an outhouse - if there are long pipe runs back to the kitchen tap, or from other heating systems, then it would mean longer waiting time for hot water to come through (and more wasted heat).

rodred

quentingargan wrote: »

A long pipe run from the panel to the cylinder causes huge heat loss in the solar water heating system - it is always best to keep that pipe run as short as possible. I would have thought that would be a lot better to locate and isolate the pump in such a way that it doesn't transmit noise.

Also, it depends on where you could locate such an outhouse - if there are long pipe runs back to the kitchen tap, or from other heating systems, then it would mean longer waiting time for hot water to come through (and more wasted heat).

thanks for getting back, it would be located on the other side of the wall to the boiler inside the utility. all the pipes would be lagged to reduc the
heat loss.
is it a good idead to have a pressurised cylinder with 300l of water in the
attic if anything went wrong??
i suggested to box in the pump and insulated the hell out of it on all sides.. and also have the cold water and toilets gravity fed, so as to
minimise the amount the pump is running...
any suggestions??