Very very low hot water flow

[Tezzer2022]

Hello,
I’ve been doing my first refurbishment is a two bed flat with a bathroom and ensuite . Learnt a lot and been grateful for input’s especially from Shaun. The customer had ordered swan neck mixer taps for kitchen, bathroom and ensuite. On installing then all the hot water flow is none existent in the kitchen which has a tall swan neck tap. When the low lying bath hot water is running there is no flow in the ensuite or kitchen.
I have no idea what the flow was like pre refurb but I suspect that moving from low taps to swan neck has exacerbated the hot water flow issue. The flat has a direct gravity fed cylinder.
I’m a novice in this but I suspect that a salamander pump or a pressurised direct cylinder would improve the flow. Are there any conclusive test that can be carried out before I recommend to the customer to go with a pump/pressurised cylinder.
Kind Regards
Tezzer

 

[exedon2]

More than likely you have fitted high pressure taps on low pressure hot system.
Pressurised cylinder would be a cure but a correctly sized/fitted whole house pump would do the job.
Not salamander! Not what they were
Stuart Turner monsoon every time.

 

[fowlerboi]

How much head is there?

Are the taps suitable for low pressure? What is the minimum required head on them?

If you're going down the pump route how big is the storage tank?

How big is the cylinder?

 

[Ben-gee]

If you go down the unvented cylinder route you will not be able to install it as you would have to be G3 registered.

 

[snowhead]

As it's a flat does it have a Fortic cylinder like the one below or is the cold from a central higher level tank feeding all the flats?
Have you checked if all / any valves are sheared or seized or just part closed?

 

[Tezzer2022]

More than likely you have fitted high pressure taps on low pressure hot system.
Pressurised cylinder would be a cure but a correctly sized/fitted whole house pump would do the job.
Not salamander! Not what they were
Stuart Turner monsoon every time.

The customer pre purchased all the taps etc. The pump you suggested looks like the best option rather than replacing the vented system. Thanks for the recommendation.

More than likely you have fitted high pressure taps on low pressure hot system.
Pressurised cylinder would be a cure but a correctly sized/fitted whole house pump would do the job.
Not salamander! Not what they were
Stuart Turner monsoon every time.

 

[Tezzer2022]

How much head is there?

Are the taps suitable for low pressure? What is the minimum required head on them?

If you're going down the pump route how big is the storage tank?

How big is the cylinder?

The flats water tank is quite small. I'd say about 90 litres. The cylinder is again about 170 litres. I suspect gravity is playing a part here as both components are in an airing cupboard, with the tank just above the cylinder.

 

[Tezzer2022]

As it's a flat does it have a Fortic cylinder like the one below or is the cold from a central higher level tank feeding all the flats?
Have you checked if all / any valves are sheared or seized or just part closed?

I check the valves and all seemed to be fully opened. The bath being the lowest seems to run fine so I kind of deduced from that that the valves are opening ok. The system is conventional tank (90 litre-ish). Above the cylinder 170 litres-ish. I suspect gravity is playing a part here as both components are in an airing cupboard. Not alot of height.

 

[Ben-gee]

If you’re fitting a single impeller pump for the hot, you need the hot cylinder to be fed from a cold water tank of at least 25 gallons. If it’s a fortic tank (combination cylinder) then you should not pump it.

 

[fowlerboi]

Might struggle to pump that with such a small cistern

You can get away with not pumping it but it will mean changing the taps for decent low pressure ones and making sure the pipe work doesn’t have any restrictions. Use swing check valves or full bore ones and full bore ball'o'fixes

Are the colds all mains pressure or are they from the cistern?

 

[ShaunCorbs]

It’s calling out for an unvented as it’s a fortic cylinder