It is also advisable when installing a system, to provide gate valves on all 3 connections to make changeout easy without the need for a complete time wasting drain down. In the case of replacing a spring-return with a MOMO valve this requires change-over contacts at the room thermostat or progstat and an extra wiring conductor between the 'stat and the valve. Next post: These are used to control the flow of heated water from the boiler, which would typically flow to the hot water cylinder, radiators or both.
The boxes housing the equipment are normal white plastic one gang surface socket outlet boxes. The design has the following features:.
As has already been mentioned, a common failure mode is the motor burning out: You can keep up to date with all new content on this blog by by following on Twitter. This is called a pump over run. So it sounds on and looks to be on.heating zone valve problem
Personal tools Log in. An example of how a 3-port valve integrates into a system:.
These have three plumbing connections - flow in and two outputs A and B. These appear physically identical to the 3 port valve described above, but have two operating positions - A only or B only.
Basic engineering principles tell you that a they should last longer and be more reliable in operation and b they should save a lot of energy. It seems as if the pump and the boiler act separately. To close the valve, power is removed.
When power is applied to a second wire, the motor moves the valve to position A. By Matthew Marks with thanks to Geoff Drage for data.
There are three possible positions.
Wiki reader Anthony Ford, contributed the following design modification which circumvents the situation where a valve can remain powered for an extended period even when all the calls for heat are satisfied. Three port valves are available in a 'diverter' format.
Completely at a loss!