Does anyone know about motorised valve zones, my honeywell heating has 3
motorised valves v4043h, one for heating and the other two for heating
upstairs and for downstairs, upstairs can be on why downstairs is off
and vice versa. On turning on the honeywell thermostats downstairs came
on and upstairs came on for 5 mins and failed, tried again nothing
upstairs and today it did the same as first turn on rads started to heat
up and then failed after 5 mins. Does anyone know if its the switch
maybe got a bit sticky or the motor in the powerhead. Or something
else, assuming its not pump or boiler failure as downstairs is still
working. I am also guessing the powerhead itself is getting power due
to attempting to start.
> Does anyone know about motorised valve zones, my honeywell heating has 3
> motorised valves v4043h, one for heating and the other two for heating
> upstairs and for downstairs, upstairs can be on why downstairs is off
> and vice versa. On turning on the honeywell thermostats downstairs came
> on and upstairs came on for 5 mins and failed, tried again nothing
> upstairs and today it did the same as first turn on rads started to heat
> up and then failed after 5 mins. Does anyone know if its the switch
> maybe got a bit sticky or the motor in the powerhead. Or something
> else, assuming its not pump or boiler failure as downstairs is still
> working. I am also guessing the powerhead itself is getting power due
> to attempting to start.
BY FAR, the most common cause of Honeywell zone valves not to work
is because the motor is stuck and needs a shot of a light lubricating
oil like WD-40.
I have 21 Honeywell V8043C zone valves in my building, and they're
similar to yours in many respects. The cifference between a V8043 and a
V4043 is that the 8043 operates on 24 volts AC, whereas the 4043
operates on a different voltage; either 120 Volt 60 Hz in North America
or 220 V 50 Hz in Europe.
Your zone valve should look like this:
You'll find that under the cover stamped "Honeywell", there will be a
small electric motor that looks like this:
You'll notice that motor itself has a cover with the word "Synchron"
stamped on it three times. If you look closely, there will be a bit of
a dimple on that motor cover, and you can see it in the image directly
under the "ro" in the closest "Synchron". There will in fact be three
such dimples around the circumference of the motor cover. You need to
put something sharp (like a paint scraper blade) under that little
dimple and lift up to pop the cover off the motor. When re-installing
the cover, try to reinstall it with a dimple on the cover fitting into a
similar dimple on the motor housing.
Now, for every zone valve in your house you will have a thermostat
controlling the power to that zone valve. The thermostat for the
upstairs zone valve will be upstairs and the thermostat for the
downstairs zone valve will be downstairs, etc.. What you need to do is
take the cover off the zone valve and then pop the cover off the zone
valve motor and have a helper turn the thermostat for that zone valve up
and down as high and low as it'll go in both directions. Watch the zone
valve motor to see if it turns. If it turns, spray the motor with some
WD-40. If it doesn't turn, try turning the motor manually with a
popsicle stick or pencil or something. You have higher voltage in your
zone valves than mine, so don't touch anything inside the motor with
your fingers. 99% of the time when a Honeywell zone valve doesn't work,
it's because the motor was stuck. All you need to do is give it a shot
of a very light lubricating oil to get it to start working again.
You don't need to know the rest...
The reason why zone valves will often stick is because people don't turn
their thermostats down in the summertime. Instead, they leave the
thermostat set to the same position it was during the winter. The
problem is that even in the summer with the windows open, it can get
cool enough at night that the thermostat could actually be calling for
heat. That means it's sending power to the zone valve motor to keep the
zone valve open all night long. That won't provide any heat because the
boiler is shut off for the summer, but what it does do is cause the zone
valve motor to get warm and stay warm all night, every night all summer
long. And, that just makes the oil thicker so it's harder for the
applied voltage to get the motor to start turning.
If you turn your thermostats all the way down at the end of every
heating season, you're zone valves won't stick when you need them to
work at the start of every heating system.
Raylea wrote the following on 10/19/2012 5:04 PM (ET):
I am not a heating or plumbing professional.
Just last week I had the same problem. One zone was not getting heat
while the other two were heating OK.
All I did was to manually push the tab that stuck out of the bottom of
the regulator all the way to the right. You will find that it feels like
it is spring loaded. After that and since, the heat is working and the
regulator is working. It opens and closes as designed.
Someone else has mentioned that it might need some oil. I didn't use any.
That tab is the manual open lever on Honeywell zone valves. Since most
Honeywell zone valves are normally closed and require electrical power
to open them, the manual open lever is provided so that you can open the
zone valve manually if there's a problem with the valve or the wiring to
To open the zone valve, you simply slide the lever as far as it'll go to
the right, and then lift up on it as the spring pulls it back. The
lever will catch on that notch in the zone valve body, and remain in the
open position. The picture above shows the valve set in the manually
open position. Erie zone valves have a similar feature.
You are correct that the lever is spring mounted. Operating that lever
also spins the zone valve motor, so if your motor is stuck, operating
the lever could very well un-stick it.
If the lever doesn't move smoothly, the probable cause is broken teeth
in the transmission of that one piece motor/transmission pictured in my
first post. You can buy those Synchron motors at any plumbing
wholesaler if you pay cash. I don't know if home centers carry them,
but they should because they're used on both Honeywell and Erie zone
valves, so they're very common.
You should also be aware that all Honeywell zone valves made since about
1980 allow you to replace what you're calling the "regulator" (typically
called the "head") without having to drain any water out of your heating
system. There will be two screws holding a brass plate to the valve
body, and two other screws holding the head to the brass plate. You
simply remove the screws holding the head to the brass plate and put a
new head on. The head will only go on one way, so you can't put it on
backwards. Honeywell zone valves are quite DIYer-friendly that way.
On Friday, October 19, 2012 5:04:52 PM UTC-4, Raylea wrote:
Is there a lube that can be applied to the valve shaft?
'Tis the season... I have a few of these valves where the valve itself (the shaft I believe) has a lot of drag... the motor won't crank the valve the last little bit and it never closes the switch, and in some cases the valve won't quite close all the way.
I have replaced a few of the motors over the years, and have at times removed the motor assembly and turned the valve by hand to see how much resistance ther was, so I know it is the valves being 'draggy'.
I have gone so far as to work the valve shaft back and forth and added some oil to the shaft, this helps, but not quite enough, and not for long.
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