Shower Pump on air to water Unvented Cylinder?

[thegrizzlyone]

Hi,

I'm in my new build 2 years and the shower pump has died.
I have an air to water unit downstairs is in the utility which I've been told is unvented and pressurised. The cold water feed into this cylinder is from the attic tank, not the mains as I turned off the mains stopcock to see if hot water would still flow.
After contacting the manufacturer and giving them the above information, I was told that their pumps are for gravity fed systems only and can't be used for unvented cylinders.
I have talked to 7 other air to water homeowners and they all have shower pumps. Surely all these plumbers can't be wrong?
Now the pump was installed badly as the AV hoses are bent (see picture).
Also as the pump is installed beside the hot water cylinder in the utility and is pumping to 2 showers upstairs, should this pump be a negative head?

Thanks in advance

 

[ShaunCorbs]

Sounds like the hot is fed from the attic tank eg you use hot water and the tank refills in the loft ?

 

[thegrizzlyone]

Sounds like the hot is fed from the attic tank eg you use hot water and the tank refills in the loft ?

Yes, that's what seems to be happening so there's no mains connected to the unvented cylinder.

Is a pump ok in this scenario?

 

[ShaunCorbs]

Yes, that's what seems to be happening so there's no mains connected to the unvented cylinder.

Is a pump ok in this scenario?

Yes fine it’s just a gravity cylinder just need to follow stnd pump fitting practices when installation

 

[thegrizzlyone]

Yes fine it’s just a gravity cylinder just need to follow stnd pump fitting practices when installation

I was confused because the air to water cylinder is described an unvented in the manual but must depend on the cold water source and the pump manufacturer said my warranty is void.

Negative head recommended over positive head? Cold water in loft goes down to ground floor hot water cylinder and then upstairs to 2 showers?

Appreciate the response

 

[ShaunCorbs]

I was confused because the air to water cylinder is described an unvented in the manual but must depend on the cold water source and the pump manufacturer said my warranty is void.

Negative head recommended over positive head? Cold water in loft goes down to ground floor hot water cylinder and then upstairs to 2 showers?

Appreciate the response

You can still use it as a gravity cylinder though just overbuilt I would go back to the pump manufacturer and say the cylinder and pump are fed from a cold water tank

 

[thegrizzlyone]

You can still use it as a gravity cylinder though just overbuilt I would go back to the pump manufacturer and say the cylinder and pump are fed from a cold water tank

Ya, they said the fact the anti-vibration hoses are very bent and not straight also invalidates the warranty.
I'll get onto builder and see if he'll do anything about his plumber not installing it correctly.

Thanks for help