AHU-01

Fixed Point Control System · v0.1 concept

Running Running Occupied Supply and extract proved

Fire alarm Healthy

E-stop Healthy

Frost stat Healthy

Refrig. leak Healthy

Supply path

Outside air

6.4°C

Fresh air damper

100%

Open · exhaust 100%

Filters · DP

PanelClean BagDirty

Bag DP above 250 Pa

Heat recovery

82%

On recovery

LTHW heating

34%

CHW / DX

DX off · 0%

Supply fan

60%

Proven

Supply air

18.8°C

47% RH

Return / room

Extract fan

56%

Proven

Extract filter

Clean

Extract

21.3°C

43% RH

Room CO₂

970ppm

Room

21.5°C

Schedule

07:00–19:00

Demo hold, not a calendar

Alarms

1 unacknowledged

Unacknowledged Medium

Supply bag filter dirty

Filters · differential pressure switch · trip about 250 Pa

Raised 14:06

Setpoints

Supply air temperature

°C

Deadband 1.0 K. Heating below the band, cooling above it.

Room CO₂

ppm

Fan speed runs from 30% to 100% as CO₂ rises 400 ppm above setpoint. Extract tracks 4% below supply.

Humidity high limit

80% RH on the supply air. Cooling is held back if it is reached.

Occupancy

Hand / auto / off

Auto follows the simulation. Hand holds a value. Off forces it off. A safety trip overrides hand. Overrides are logged.

Fresh air damper

100%Safety

Hand %

Exhaust damper

100%Safety

Hand %

Recirculation damper

0%Safety

Hand %

Heat recovery

82%Safety

Hand %

LTHW heating valve

34%Safety

Hand %

CHW cooling valve

0%Safety

Hand %

DX capacity

0%Safety

Hand %

Supply fan

60%Safety

Hand %

Extract fan

56%Safety

Hand %

Simulate a safety trip

Opens the contact in this browser only. Fans stop, dampers close, and the alarm latches until reset. Frost also drives the heating valve to 100%.

Concept only · not for construction · Fixed Point Engineering Ltd. On a real air handler the fire alarm, emergency stop, and frost thermostat are hardwired. Contact Fixed Point Engineering from your job pack, or fixedpointengineering.co.uk.