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Andrew Smith
Andrew Smith, Plumber
Category: Plumbing
Satisfied Customers: 3723
Experience:  City and Guilds qualified plumber
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I have an issue with my CH stat - it doesn't want to turn

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hi I have an issue with my CH stat - it doesn't want to turn the boiler on anymore I have replace batteries - its a honeywell dt90 I think
Assistant: I'll do all I can to help. How long have you been dealing with this?
Customer: few days. I could kickstart it yesterday by power cycling the wireless stat but thats not working today
Assistant: Do you plan on doing the work yourself?
Customer: if its simple
Assistant: Anything else we should know to help you best?
Customer: RF to the relay unit seems ok as the green LED goes off/on when I turn off/on the power button on stat
Assistant: Did you double-check the thermostat? And what about the unit's filters?
Customer: stat may be faulty I have bumped up desired temp to 35C but still wont kickstart the boiler
Do you have the make and model of the boiler?
Customer: replied 1 month ago.
boiler is baxi but doesn't state model number anywhere on it
Sorry at work so can't talk
Is it a combi or standard boiler?
Customer: replied 1 month ago.
its a combi I think - looks like the ecoblue boiler from images on the web
Can you put the transmitter under the boiler and see if they resync and you regain control.
Customer: replied 1 month ago.
the receiver is upstairs in a cupboard with the programmer - boiler and stat are downstairs.I took the stat upstairs and power cycled a couple of times next to the receiver and this kickstarted the boiler yesterday but not today
Can you leave it there for a short time and see if it goes through a couple of sequences automatically?
Customer: replied 1 month ago.
still nothing happening with the boiler and the room stat is not showing the flame indicator to show heat demand?
Can you turn the temp up on the transmitter until it does and then see if the boiler fires?
Customer: replied 1 month ago.
i already have it set to max = 35C
Ok, if you are not getting the flame signal then the boiler will not fire.
It looks like a faulty transmitter.
Customer: replied 1 month ago.
that is what I am thinking. Looks like they are around £30 so may be best to buy one and try it out. If I buy another Honeywell stat will it automatically sync up to my receiver?
I have said yes before and it has come back to bite me!
Definitely not if more than 3 years old.
Customer: replied 1 month ago.
ok i went out and bought a new honeywell dt92e room stat and have bound it to the receiver unit in the boiler cupboard.everything seems to have gone ok during the procedure but the boiler is still not turning on even with new stat
the stat has a flame?
Any indication on the receiver?
Customer: replied 1 month ago.
the stat now shows a flame and I see a green led come on the receiver when I switch on the stat
Ok, appears to be working now.
Can you tell me what the boiler does (any clicking?)
I assume the hot water is still Ok?
What does the pressure gauge read?
Customer: replied 1 month ago.
nothing at all from the boiler - no sound/lights or response when pressing reset buttonsthere is some hot water from the tap but this could be from the tank as according to programmer the boiler should be boiling hot water at this time.i bumped up the pressure to 1.5 bar at the EV a few days back as this was low - will go up and check it again now
Customer: replied 1 month ago.
checked the pressure at the EV and this is still 1.5 bar so seems OK?however I notice that the lever on the motorised valve that appears to go the CH system is stuck half way across.I cannot push this to a forced open position as it is stuck hard - could this motor have failed and caused the boiler not to fire?
Sorry, I thought you said a combi?
Is it a system boiler?
Do you have a cylinder?
If you have a motorised valve then the stat will power it open and the valve will turn on the heating.
If the valve is not opening then the boiler will not fire.
Can you take the head off and grease the pin?
Do you have a make and model?
Customer: replied 1 month ago.
it is a honeywell silver box style valve. I bought a spare at the shop in case the motor had gone.dont think I have any grease for the pin - would wd40 suffice?or I could try and replace the motor?
Changing motor will not work unless you can get the pin to move with the head off
Customer: replied 1 month ago.
I disconnected the power to the motorised valve and this seemed to free up the lever to move freely left and right and automatically return via the spring.Once I reconnected the power the valve crackled into life and the boiler fired up. Would this indicate that the motor is somehow getting jammed or perhaps a fault in the wiring?Thanks
best to swap the head or the complete valve.
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