- Messages
- 36
The Honeywell VT5005T referred to (in a link) by John.g is indeed
a more flexible version of the Caleffi Autoflow 127. The Caleffi valves (the 127 and its big brothers the 121-126) have changeable fixed flow-rate cartridges whereas the flow-rate of the V5005T is set by the installer and can be varied.
It is horses for courses: the V5005T is twice the price of a 127 but you get 'variability' for your money. However, the V5005T is intended for controlling the flow and temperature of its inputs - it is not just a flow limiter, and the temperature control is regulated by its actuator.
Of technical interest - overkill for a domestic installation - are Honeywell’s electrical actuators (e.g. the M4410E/K) that can be bolted on, such that the V5005T operation can be overridden proportionately (i.e. not just on/off) by an external controller with variable (PWM) output. In an ideal world the V5005T would be normally off (no flow), and the boiler would have a suitable PWM output that would enable it to signal to the V5005T actuator when input flow rate was falling towards the minimum.
(Whether the VT5005T can be set to ‘no-flow’ until remotely actuated I don’t know and the documentation I have seen doesn't say)
a more flexible version of the Caleffi Autoflow 127. The Caleffi valves (the 127 and its big brothers the 121-126) have changeable fixed flow-rate cartridges whereas the flow-rate of the V5005T is set by the installer and can be varied.
It is horses for courses: the V5005T is twice the price of a 127 but you get 'variability' for your money. However, the V5005T is intended for controlling the flow and temperature of its inputs - it is not just a flow limiter, and the temperature control is regulated by its actuator.
Of technical interest - overkill for a domestic installation - are Honeywell’s electrical actuators (e.g. the M4410E/K) that can be bolted on, such that the V5005T operation can be overridden proportionately (i.e. not just on/off) by an external controller with variable (PWM) output. In an ideal world the V5005T would be normally off (no flow), and the boiler would have a suitable PWM output that would enable it to signal to the V5005T actuator when input flow rate was falling towards the minimum.
(Whether the VT5005T can be set to ‘no-flow’ until remotely actuated I don’t know and the documentation I have seen doesn't say)
Last edited:
