Size of Cold Supply to Hot Cylinder with Pump

[Invisible-Man]

Hi,

I have read on the forum that it is advisable to up the size of the water supply from the cold water tank to the hot cylinder if using a shower pump (this would be a 28mm feed).

My question is: If the pump is to supply all of the hot (with no other tappins for hot from cylinder), would It make any difference being 28mm cold feed opposed to 22mm.

I know that this is advised in case of emptying hot cylinder but thought that as there is only one 22mm pump out, a 22mm feed from the cold storage tank would be ok.

This will be a new instalation (not done yet) so it is not a matter of changing pipe work to one or the other, just a case of getting it right, but not using 28mm unnecessary!

Also the cold connection to the cylinder is 1" male, does this take a special kind of fitting/connection (tank connector) or just a 1" female to whatever with PTFE!

Many many thanks !!!

 

[doitall]

For starters the connection will be a maleiron and not a female.

Conex 302 is the compression coupling.

Size depends on the pump pressure.

If a gravity circuit is 22mm then it stands to reason that if you treble the demand then the pipe has to treble the supply or it will suck air, and or drain the tank down to the connection.

 

[Invisible-Man]

For starters the connection will be a maleiron and not a female.

Conex 302 is the compression coupling.

Size depends on the pump pressure.

If a gravity circuit is 22mm then it stands to reason that if you treble the demand then the pipe has to treble the supply or it will suck air, and or drain the tank down to the connection.

The pump is a 3 bar, I assume from your reply that you would go for the 28mm!

 

[doitall]

No, for a 3bar pump on whole house I would consider 35mm

 

[Invisible-Man]

For starters the connection will be a maleiron and not a female.

Conex 302 is the compression coupling.

Size depends on the pump pressure.

If a gravity circuit is 22mm then it stands to reason that if you treble the demand then the pipe has to treble the supply or it will suck air, and or drain the tank down to the connection.

I can confirm that the connection on the cylinder is 1" male, needing a female connector, preferably on a 90 degree elbow/bend to save space.

 

[doitall]

For starters the connection will be a maleiron and not a female.

Conex 302 is the compression coupling.

Size depends on the pump pressure.

If a gravity circuit is 22mm then it stands to reason that if you treble the demand then the pipe has to treble the supply or it will suck air, and or drain the tank down to the connection.

I can confirm that the connection on the cylinder is 1" male, needing a female connector, preferably on a 90 degree elbow/bend to save space.

Perhaps you had better say what cylinder it is in that case, as the cold feed is always taped femail.

 

[Agile]

I seem to remember that BS 747 or similar required a 28 mm feed to cylinder in aby situation.

If you are going to suck HW out then a larger pipe as DIA says is required!

Tony

 

[Invisible-Man]

I seem to remember that BS 747 or similar required a 28 mm feed to cylinder in aby situation.

If you are going to suck HW out then a larger pipe as DIA says is required!

Tony

It is a new Gledhill E7 cylinder 1" female for hot out!

 

[Agile]

Its the size of the feed pipe we are talking about!

The inlet or outlet connection size is irrelevant.

The cylinder connections are sized for normal gravity usage. Sucking water out with a pump creates a conpletely different set of operating parameters.

Tony

 

[Invisible-Man]

Its the size of the feed pipe we are talking about!

The inlet or outlet connection size is irrelevant.

The cylinder connections are sized for normal gravity usage. Sucking water out with a pump creates a conpletely different set of operating parameters.

Tony

So Agile, would you think that 28mm supply would be sufficient, it is only a small 1 bedroom flat, 1 sink, 1 basin and 1 shower to be pumped on the hot side with the cold being mains!

Thanks

 

[doitall]

Its the size of the feed pipe we are talking about!

The inlet or outlet connection size is irrelevant.

The cylinder connections are sized for normal gravity usage. Sucking water out with a pump creates a conpletely different set of operating parameters.

Tony

So Agile, would you think that 28mm supply would be sufficient, it is only a small 1 bedroom flat, 1 sink, 1 basin and 1 shower to be pumped on the hot side with the cold being mains!

Thanks

If you are talking about an unvented cylinder then forget the pump unless you are thinking of a break tank and pump set.

 

[Invisible-Man]

Its the size of the feed pipe we are talking about!

The inlet or outlet connection size is irrelevant.

The cylinder connections are sized for normal gravity usage. Sucking water out with a pump creates a conpletely different set of operating parameters.

Tony

So Agile, would you think that 28mm supply would be sufficient, it is only a small 1 bedroom flat, 1 sink, 1 basin and 1 shower to be pumped on the hot side with the cold being mains!

Thanks

If you are talking about an unvented cylinder then forget the pump unless you are thinking of a break tank and pump set.

Vented system

 

[doitall]

Its the size of the feed pipe we are talking about!

The inlet or outlet connection size is irrelevant.

The cylinder connections are sized for normal gravity usage. Sucking water out with a pump creates a conpletely different set of operating parameters.

Tony

So Agile, would you think that 28mm supply would be sufficient, it is only a small 1 bedroom flat, 1 sink, 1 basin and 1 shower to be pumped on the hot side with the cold being mains!

Thanks

If you are talking about an unvented cylinder then forget the pump unless you are thinking of a break tank and pump set.

Vented system

With a cold mains feed, I don't think so.

In any case you cannot connect a pump to the mains.

What model is the E7

 

[Invisible-Man]

Its the size of the feed pipe we are talking about!

The inlet or outlet connection size is irrelevant.

The cylinder connections are sized for normal gravity usage. Sucking water out with a pump creates a conpletely different set of operating parameters.

Tony

So Agile, would you think that 28mm supply would be sufficient, it is only a small 1 bedroom flat, 1 sink, 1 basin and 1 shower to be pumped on the hot side with the cold being mains!

Thanks

If you are talking about an unvented cylinder then forget the pump unless you are thinking of a break tank and pump set.

Vented system

With a cold mains feed, I don't think so.

In any case you cannot connect a pump to the mains.

What model is the E7

Are you that slow?

You have been no help at all so far, if you cannot get down off your pedestal as a plumber with others not quite so qualified as yourself, then do not bother answering posts with clever comments!

We all know by now that the hot cylinder is being fed via cold storage tank and that I was referring to the outlet at the cold taps etc being mains fed.

If you are on here to help doitall then help !!!

 

[doitall]

So Agile, would you think that 28mm supply would be sufficient, it is only a small 1 bedroom flat, 1 sink, 1 basin and 1 shower to be pumped on the hot side with the cold being mains!

Thanks

Sorry I took that to read the cold feed was mains.

It would still be useful if we knew the model E7