water pipe

[john b.]

Hi. All.

I am considering running my water pipes ( water pump to all services etc) in 15mm push fit plastic. Is this O.K. or as somebody suggested should I use 22mm. The interior length is 30ft. What is the norm.

Many Thanks.

john b.

[DHutch]

All our domestic water pipe is 15mm plasitc push fit. except the bits in the engine room which are 15mm copper.

- As far as i know thats the norm, certainly it works fine.

 

Some of our house plumbing done in 22mm, but i can see it making any diffrence if you just using a normal pump like th surflo, and i cant see the point in having anything bigger, you'll only fill up more often!

 

 

Daniel

[Richard Bustens]

I used 22 for the runs and T off in 15 . if you do use 22 dont get the big roll's they are buggers to uncoil.

 

Dan

And how will he use more water and have to fill up more ?

[DHutch]

And how will he use more water and have to fill up more ?

Im just saying that if use a larger pump and pipe that water can/will come out faster, so without meaning to you'd end up using more water.

- A 10 litre/min shurflo is more than enough. (but not really enough to warrent 22mm pipe)

[Big COL]

Hi. All.

I am considering running my water pipes ( water pump to all services etc) in 15mm push fit plastic. Is this O.K. or as somebody suggested should I use 22mm. The interior length is 30ft. What is the norm.

Many Thanks.

john b.

 

15mm is the norm, with it being a pressurised system there is always enough volume of water delivered through the outlets. Unless you go for 22mm thoughout including all outlets you will gain no advantage. Stick to 15mm.

[john b.]

15mm is the norm, with it being a pressurised system there is always enough volume of water delivered through the outlets. Unless you go for 22mm thoughout including all outlets you will gain no advantage. Stick to 15mm.

 

 

Woops.

Thanks guys, 15mm it is.

 

johnb.

[Bones]

I have 15mm from my accumulator to the taps which carries cold water. I want to fit the hotwater this weekend (hahahahahaha). Do I continue this cold water 15mm pipe braching off for bathroom taps along the way and then attach it via a non-return valve(to stop hot water returning down the cold) into the calorifier, or do I need to do it differently?

[Big COL]

I have 15mm from my accumulator to the taps which carries cold water. I want to fit the hotwater this weekend (hahahahahaha). Do I continue this cold water 15mm pipe braching off for bathroom taps along the way and then attach it via a non-return valve(to stop hot water returning down the cold) into the calorifier, or do I need to do it differently?

 

Hi Bones

 

Thats OK I didn't even use a non return, the water doesn't get thet hot at low level. All that may happen is a small pressure rise on the cold feed due to expansion as the water heats up.

[Bones]

Hi Bones

 

Thats OK I didn't even use a non return, the water doesn't get thet hot at low level. All that may happen is a small pressure rise on the cold feed due to expansion as the water heats up.

 

 

ah... does that matter, or do I put an expansion thing on the hot water side (what does one of those look like?)

 

ah... does that matter, or do I put an expansion thing on the hot water side (what does one of those look like?)

 

ALSO - is it Heb20 I use - and where do I get it... homebase doesn't have it but their own brand but I don't know if I can use that for this?

[DHutch]

ah... does that matter, or do I put an expansion thing on the hot water side (what does one of those look like?)

 

ALSO - is it Heb20 I use - and where do I get it... homebase doesn't have it but their own brand but I don't know if I can use that for this?

The expantion-tanks/acumulators are a steel tank, with a rubber diafram half way up, with air in the top half, and the water on the bottom, so as the water expands, it compresses the air.

 

We have a small one (2L ?) just after our water pump, and then i dont think there is a non-return valve between that and the calorifyer.

- Then we also have a slightly larger expantion tank on the centralheating loop, as its a closed system.

 

Our boat is done in Hep20, but thats just because they where the first, and 15years ago, there wernt many other brands of push-fitt tube.

- I would be suppresed if there was a big diffrence in quality.

 

 

Daniel

[John Orentas]

The best way is the old way. Half inch dia. high pressure hose as you would use on pneumatics, you can buy all the brass connectors quite cheaply, never leaks, on need to drain off for frost, you can even get a high temp. version for hot water.

 

Pipe an entire boat in one day easily.

[Bones]

so an accumulator is the same as an expansion tank?

[Keeping Up]

so an accumulator is the same as an expansion tank?

Yes, and ours is the simpler type than described. From Jabsco, it is nothing more than a container with a fitting for the pipe at the bottom, and a stopper at the top. You don't pressurise it, you just turn things on and it sits at about half full of air but every few months some of the air will have dissolved away so you turn off the pump and release the pressure, then unscrew the top to let more air in.

 

On non-return valves, I was very puzzled because I knew we had one but couldn't find it. Eventually I gave up and asked the boatbuilder, he explained he always puts the valve AFTER the hot tank. If it's before the tank, then the hot system has no room for expansion so every time it heats up it dribbles out of the pressure-release valve. Putting the valve after the tank means no increase in pressure in the hot pipes, and the expansion in the hot tank is taken up by just a small extra compression of the accumulator; the valve works just as well after the tank, water still can't syphon backwards because to do so would create a vacuum in the tank.

 

Allan

[John Orentas]

And while we are at it, why not get a decent quality pressure switch and pressure gauge, gives good control of pressure and you can see what is going on. So many people throw away perfectly good pumps simply because the pressure switch has jacked it in.

[DHutch]

so an accumulator is the same as an expansion tank?

Yes, there exatly the same as the things you get in domestic pumbing (we have a 36l on top of our imersion cylinder at home) between the non-return valuve and the tank.

 

 

Eventually I gave up and asked the boatbuilder, he explained he always puts the valve AFTER the hot tank.

I cant see what you get for a non-return valuve after the tank!

- If you have one at all, its got to be before the tank, with some sort of expantion tank after it surely?

 

 

The expantion tanks we have are just small versions of domestic ones (link

- With a schrader valve on the top to pump in replacement air, which we pre-load to 2bar (the surflo is about 3, so we recon thats about right)

 

 

Daniel

[Bones]

And while we are at it, why not get a decent quality pressure switch and pressure gauge, gives good control of pressure and you can see what is going on. So many people throw away perfectly good pumps simply because the pressure switch has jacked it in.

 

 

I seee - now I understand... however, I already have an accumulator - easy peasy!!! I had that fitted when I had a water tank installed underneath the bow (rather than numberous bags up and down the boat...!!! don't ask)

 

I had a look at the calorifier this afternoon and have done a search on line... The calorifier was installed before but using washing machine hose, and bits of copper - is this alright to re-use? The previous person had also used washing machine hose for all the water plumbing, but I don't like this for cold water as alge can grow inside and thats not nice apparently.

[lymmranger]

Make sure you check the max pressure that your calorifier will take...

 

I cant remember figures but I had to get a lower pressure pump than was normal

 

(I think mines 10psi normal is 35psi?????)

 

more modern calorifiers make take more but remember to rate your pressure "blow off" valve to match!

[Amicus]

so an accumulator is the same as an expansion tank?

 

No it aint, an accumulator is the red bit herein http://www.cleghorn.co.uk/item.asp?ls=&v=A...1534C10&id=2750

an expansion tank is a smaller version of the cistern in many domestic lofts

[Bones]

Make sure you check the max pressure that your calorifier will take...

 

I cant remember figures but I had to get a lower pressure pump than was normal

 

(I think mines 10psi normal is 35psi?????)

 

more modern calorifiers make take more but remember to rate your pressure "blow off" valve to match!

 

Oh horrors, this is getting more complicated. Good tip.

[lymmranger]

Oh horrors, this is getting more complicated. Good tip.

 

Well dont worry too much - you cant afford to lose any more weight!!!!

[DHutch]

No it aint, an accumulator is the red bit herein http://www.cleghorn.co.uk/item.asp?ls=&v=A...1534C10&id=2750

an expansion tank is a smaller version of the cistern in many domestic lofts

This is what i beleave to be an expantion tank. http://www.thermotechs.com/ExpansionTank.htm

- Which is eactly what is inside that "red bit" you refer to.

- Are you sure you dont mean header tank?

 

 

Daniel

[Bones]

This is what i beleave to be an expantion tank. http://www.thermotechs.com/ExpansionTank.htm

- Which is eactly what is inside that "red bit" you refer to.

- Are you sure you dont mean header tank?

Daniel

 

 

Oh dear... whats a header tank and do I need one?!

 

This is what i beleave to be an expantion tank. http://www.thermotechs.com/ExpansionTank.htm

- Which is eactly what is inside that "red bit" you refer to.

- Are you sure you dont mean header tank?

Daniel

 

 

are you sure Daniel... coz if it is then how come the pump kicks in when the level gets low... - and surely an expansion tank should be purely for expaning and not storing the water?

[Big COL]

Oh dear... whats a header tank and do I need one?!

are you sure Daniel... coz if it is then how come the pump kicks in when the level gets low... - and surely an expansion tank should be purely for expaning and not storing the water?

 

Bones

 

An expansion tank and accumulator are basically the same animal, Depending on how you install them, An expansion tank is normally used on a sealed central heating system, it is there only to take up the expansion of the water, if the system was of an open type with a header tank then there is no need for one to be used.

When used as an accumulator it helps to smooth out the cold water pumps pulses and if adjusted correctly will help stop the pump short cycling (cutting in and out )

For the simple question you first asked things have escalated a bit. If I was doing the job I would do it exactly as you described. Check first that your calorifier has a PRV (Pressure relief valve fitted) Most of todays calorifiers are tested to at least 5bar 70psi some are only tested to 3bar 42psi check what pressure your cold water pump delivers.

 

PS You do not need a header tank on your cold water supply, header tanks are used on central heating systems.

Edited January 20, 2006 by Big COL

[Bones]

Bones

 

An expansion tank and accumulator are basically the same animal, Depending on how you install them, An expansion tank is normally used on a sealed central heating system, it is there only to take up the expansion of the water, if the system was of an open type with a header tank then there is no need for one to be used.

When used as an accumulator it helps to smooth out the cold water pumps pulses and if adjusted correctly will help stop the pump short cycling (cutting in and out )

For the simple question you first asked things have escalated a bit. If I was doing the job I would do it exactly as you described. Check first that your calorifier has a PRV (Pressure relief valve fitted) Most of todays calorifiers are tested to at least 5bar 70psi some are only tested to 3bar 42psi check what pressure your cold water pump delivers.

 

PS You do not need a header tank on your cold water supply, header tanks are used on central heating systems.

 

 

OK - the accumulator has a thing of 8bar on it, and the calorifier says it should be 20psi and not above. What do I do about this?

[Big COL]

OK - the accumulator has a thing of 8bar on it, and the calorifier says it should be 20psi and not above. What do I do about this?

 

If the calorifier is labelled for 20psi safe working pressure it would be unwise to ignore this. To get over this problem you will need to fit a pressure reducing valve and a pressure gauge. The pressure gauge needs to be fitted after the pressure reducing valve which is manually adjustable. The gauge will allow you to see the pressure going into the calorifier as you set the valve, in setting the valve start at the lowest pressure possible and adjust the valve up to 20 psi. You will need to buy a valve that is adjustable down to a minimum of 1 bar/14psi. You can do this using a gate valve instead of a pressure reducing valve but it will require the gate valve to be locked off to avoid anyone accidentally opening it and over-pressuring the calorifier. You could remove the handle of the gate valve after setting, I personally would go for the pressure reducing valve.

This is assuming that your water pump is delivering over 20psi even if the pump is opperating at around this pressure you need to safegaurd the calorifier for any quirks with the pump. You can set the pump to cut out at 20psi but this will leave a short band for the pump to opperate in and this is also assuming that the pump has an adjustable pressure switch. Considering the low safe working pressure the calorifier is rated at, the safest way and to give peace of mind is to guard the calorifier with a pressure reducing valve.

Edited January 21, 2006 by Big COL