Welcome! Here are the website rules, as well as some tips for using this forum.
Need to contact us? Visit https://heatinghelp.com/contact-us/.
Click here to Find a Contractor in your area.

Honeywell Thermoelectric Actuators

I am a wholesaler trying to help a customer with a problem with Honeywell

MT4-024S-NC thermoelectric actuators used with Honeywell's 2,3,&4 port 1-1/4" radiant manifolds with valves.  The actuator is not closing the valve on the manifold completely, allowing blow-by and over heating.  It is not an isolated incident as we have already replaced eleven of them and several more currenty in service are causing problems.  We have tested voltage to the end switch and it is exactly as it should be.  Has anybody else experienced similar issues or have a solution?  Honeywell tech is stumped.


  • tim smith
    tim smith Member Posts: 2,619
    Re: blow by on radiant manifold

     Sounds like to me that he might have flow direction wrong on manifolds. If flow is not correct it will push by valve seal on some manifolds.
This discussion has been closed.