Advice needed. Issues with underfloor heating and hot water system for new build

[Gray0689]

???

1600 square feet = 149 square metres.

Or am I misunderstanding you?

House is 6500 square foot ray
500litre cylinder
6 manifolds
7 towel rads

 

[Ray Stafford]

House is 6500 square foot ray
500litre cylinder
6 manifolds
7 towel rads

Gotcha. So original 1600 should have said 6500? Makes sense now. Ta

<memo to self - read the whole thread>

 

[Gray0689]

A low loss header would of been good for that set up
But to be honest I would be thinking the plumber made a hash of that as pipework is undersized
Another good job ruined by cutting corners imho

 

[Ermintrude]

A low loss header would of been good for that set up
But to be honest I would be thinking the plumber made a hash of that as pipework is undersized
Another good job ruined by cutting corners imho

Boiler is a 1/3 of the size it should be ? 604m2 @0.150kw/m2 = 90kw just for the floors! 90kw ain't ever fitting down 28mm unless it's running at 140m/s

 

[Ray Stafford]

Heat loss calcis have been done to size the boiler to the heat output required, indicating the boiler is oversized by about

Any chance of seeing those calcs?

 

[Carrera]

let me try and answer some of the questions, btw the plumber is here at the moment!
Heat loss calcs indicate heating requirement is 27 kW, done prior to boiler selection due to level of insulation, airtightness and mechanical ventilation and heat recovery systems in place.

pipes disappearing down off the picture are flow and return to the basement manifold which sits about 6 feet away

pipework is 28mm most of the way round the house to the manifolds, changing to 22 on the top floor

Flow through hot water cylinder not working even if only one manifold is running, ie extremely low heating load.

The screed on the for is the anhydrite liquid screed, which transfers heat a lot quicker than normal and is only 50 mm thick

the T referred to behind the pump? There is no t behind the pump, the one to the right is flow out, one on the left is just an elbow leading to a T to the cylinder, followed by a T to the basement manifold

 

[Chalked]

Are my eyes deceiving me? I can definitely see two pipes coming down from the boiler, both with tees?
these go off before the pump.

 

[diamondgas]

Without checking for none return valves etc I'd say your problem could be caused by the tee before the pump, unless there's a none-return valve down stream and another pump?

Already mentioned previously, by-the-way !

 

[diamondgas]

The circled bit...

 

[Carrera]

Ok I see, the two Ts one on flow and one on return leads to manual dead ends that are used to drain system, just a bit beyond the picture, and below that is the system filling loop