Pressurised Hot & Cold System

tedimc

Folks,

Renovating a bungalow with a basement at the moment. Had planned to do the plumbing myself as I have some experience working for a few summers with a plumber. I was going to get the UFH and Geothermal done by a pro, therefore it would be just the pipes to the sinks, toilets, showers and 2nd fixing.

A few people have recommended a pressurised system, with the tanks in the basement and a pump.

I'm finding it difficult to get info on this type of setup online, and a family friend who is a plumber (who I can't really pass) has never done this before.

Would someone be able to assist with the following?

1. Should I run a ring loop for hot and cold?
2. If so, should this be an inch pipe, with 1/2 inch tee'd off it?
3. Where is the pump located in relation to the cold water tank and hot water cylinder?
4. Where does the return of the ring loop go to?
5. I presume if I get high pressure fittings, I don't need a pressure reduction valve?
6. Do I need, and where should I locate a non-return valve?
7. What size pump would I need? What should the pressure be - 3bar?
8. I've attached a rough drawing - am I missing anything?

The house will have 1 main bathroom (with bath & shower) and 4 en-suites. But unlikely to be used concurrently. Apologies for the basic questions - I would be very confident completing a gravity fed system, but have never done a pressurised system.

Thanks in advance for any feedback.

rightjob!

if he is putting a pressurised system in and has no experience be very carefull as if installed wrong they can be very dangerous.

1.theres no need to run a "ring loop",it doesnt need to be returned to the cylinder.

2.usually 3/4 is more than enough,would need to see the size of the building to put one inch in but if its a bungalow 3/4 is enough.

3.you can put the pump anywhere,be careful where you choose to put it as they do create noise and around a bedroom is not an ideal place for them

4.no return

5.high pressure fittings??if your plumber doesnt know how to install one of these systems i would choose somebody else.

6.non return valves should be fitted at the pump

7.a mains booster pump,grundfos mq or the likes

8.every safety component you can think of on a pressurised system,that cold loop doesnt need to be looped back into the tank your just going to fill the tank up that way.same for the hot.
get a competent installer.

tedimc

Thanks rightjob! - appreciate the response. Can I follow up with a few more questions?

rightjob! wrote: »

2.usually 3/4 is more than enough,would need to see the size of the building to put one inch in but if its a bungalow 3/4 is enough.

The house is about 360 sq meters, but the run for the water would be less than a 40 meters. Would there be any downside to using inch as opposed to 3/4 apart from cost? Also, any recommendations round the max length of the tee'd 1/2 inch lines?

rightjob! wrote: »

3.you can put the pump anywhere,be careful where you choose to put it as they do create noise and around a bedroom is not an ideal place for them

It can go in the basement, but wanted to ensure it was located correctly in the diagram - but that's probably no longer relevant now that I'm not looping a return.

rightjob! wrote: »

4.no return

Just a dead stop then at the last bathroom? I was under the impression that there was a return to cut down on the amount of wait time for hot water from the tap?

rightjob! wrote: »

5.high pressure fittings??if your plumber doesnt know how to install one of these systems i would choose somebody else.

Agree, but that is going to give me a whole bucket of headaches.

rightjob! wrote: »

6.non return valves should be fitted at the pump

Presumably immediately after the pump?

rightjob! wrote: »

8.every safety component you can think of on a pressurised system,that cold loop doesnt need to be looped back into the tank your just going to fill the tank up that way.same for the hot.
get a competent installer.

What else should I be including - pressure release valve, expansion vessel, etc?

K.Flyer

tedimc wrote: »

A few people have recommended a pressurised system, with the tanks in the basement and a pump.

A good suggestion, but needs to be set up properly, with consideration given to safety and potential flooding.

I'm finding it difficult to get info on this type of setup online, and a family friend who is a plumber (who I can't really pass) has never done this before.

Try to get someone else, the risks are too high and the problems too costly to rectify later.

Would someone be able to assist with the following?
Should I run a ring loop for hot and cold?

As you have said that the furthest point is nearly 40m, then a circulating loop on the hot line would be recommended as that is way too long a run to wait for hot water to arrive.
No need for one on the cold.

if so, should this be an inch pipe, with 1/2 inch tee'd off it?

With the correct water pressure boosting pump giving good strong flow rates 3/4 should be sufficient (dependant on site visit or plans)

Where is the pump located in relation to the cold water tank and hot water cylinder?

Put everything in the Basement.
Simple Explanation.
Incoming mains water feeding to cold kitchen tap with branch to large cold water storage tank (1000L). From the cold tank usually a 1" pipe feeding the booster pump, then from the pump a 1" splitting into 2 X 3/4" pipes, one pipe goes directly to cold services, the other feeds into unvented hot water cylinder.
Hot water from cylinder, under pressure from the pump, to hot services via returned loop which is circulated with a circulation pump wired into a separate timer.

Where does the return of the ring loop go to?

Back onto a pre determined connection on the hot water cylinder.

I presume if I get high pressure fittings, I don't need a pressure reduction valve?

The pump will run at approx. 3 bar +/-, all typical plumbing fittings are designed to withstand higher pressures.

Do I need, and where should I locate a non-return valve?

Usually between the cold water tank and the pump.

What size pump would I need? What should the pressure be - 3bar?

One that caters for your needs. In a set up like yours I would fit a pump that has a speed controller and typically I would set them up for at least 3 bar +/-

What else should I be including - pressure release valve, expansion vessel, etc?

Pressures release valves, expansion vessels and temp and pressure valves are all essential parts of the safety sytem on an installation of this kind.
The incorrect installation of these items can, in the event of something going wrong, cause huge amounts of damage to property.
That is why it is essential that all unvented hot water cylinder are correctly fitted by an installer who is experienced with these type of installations.

The house will have 1 main bathroom (with bath & shower) and 4 en-suites. But unlikely to be used concurrently. Apologies for the basic questions - I would be very confident completing a gravity fed system, but have never done a pressurised system.

Thanks in advance for any feedback.

If you have the advantage of a good sized basement where all of this can be installed, then I would put everything in the basement. Correctly sized and balanced you should be able to run a couple of showers at the same time without any problems.
Basically you would be installing a smaller version of the type of system that you would have in a hotel where hot water is almost instant from the taps and showers and enough pressure to run a couple of showers at the same time.
Hope that's some help.

sky6

You should also consider adding a mixer or blending valve on the system to prevent anyone getting scolded,
especially as you have Solar Water Heating.

antoinolachtnai

The risk here isn't just the risk of property damage, unfortunately. If anything goes wrong, there is a risk, however marginal, of really bad burning from superheated steam coming out of the taps. You are talking about heating water under pressure. There is no way for the heat to escape like in a gravity system. That means that the water won't actually boil at 100 C. It could superheat to an even higher temperature.

The way to avoid this, and to use an uncontrolled heat source like solar panels safely is to use a thermal store.

That sort of stuff needs to be installed by someone who really knows what they are doing. In the UK you would have to have a pressurised cylinder setup serviced by a qualified person every year (though I think a thermal store should be safer).

You should read this.

http://www.gasapplianceguide.co.uk/Mains_Pressure_Hot_Water_Systems.htm