Worcester Bosch Control Unit HT3 GSHF Regular 87377063640

The HT3 GSHF Regular control unit is the printed control assembly used on Worcester Bosch Greenstar FS CDi ErP Regular floor-standing boilers. It manages the boiler's operating sequence, monitoring inputs from the thermostat, sensors and safety devices and switching the fan, gas valve and pump accordingly. The unit is supplied as a complete control box assembly for the GSHF Regular range.

• The boiler fails to respond to a call for heat, with no display or indicator activity on the control panel.
• Repeated lockouts or fault codes that clear only after a power cycle and then return.
• The fan, pump or gas valve does not energise even though the thermostat and sensors check out.
• Intermittent shutdowns, particularly in damp conditions or after a PCB has been exposed to water ingress.
• Visible heat damage, corrosion or burnt tracks on the control board.

• Check the GC number on the appliance data badge against the compatibility table above before ordering.
• Confirm the part number on the existing control unit matches 87377063640, and note the earlier numbers 8-737-703-812-0 and 87377038120 where an older unit is fitted.
• Inspect any seals, gaskets or mounting fixings disturbed during removal and replace them if they are perished or damaged.
• This part is fitted to a gas appliance; installation must be carried out by a Gas Safe registered engineer.