Morning,

I have a conventional CH system with room and hot water thermostats
and a Drayton Mid Position valve, which I recall replacing a good few
years ago. The boiler is not firing when there is demand from the
room stat but it does when there is demand from the water stat. I
think the circuit board in the MPV is faulty, possibly what appears to
be a relay. The synchron motor works and the water valve operates.
Grateful for any thoughts.

TVMIA

"CS" wrote

Morning,

I have a conventional CH system with room and hot water thermostats
and a Drayton Mid Position valve, which I recall replacing a good few
years ago. The boiler is not firing when there is demand from the
room stat but it does when there is demand from the water stat. I
think the circuit board in the MPV is faulty, possibly what appears to
be a relay. The synchron motor works and the water valve operates.
Grateful for any thoughts.

Are there limit switches in the valve which need to "make" for the boiler to
fire?
Not sure whether the MPVs have these, may depend on manufacturer and system
wiring.

Phil

"TheScullster" wrote in message
news

"CS" wrote

Morning,

I have a conventional CH system with room and hot water thermostats
and a Drayton Mid Position valve, which I recall replacing a good few
years ago. The boiler is not firing when there is demand from the
room stat but it does when there is demand from the water stat. I
think the circuit board in the MPV is faulty, possibly what appears to
be a relay. The synchron motor works and the water valve operates.
Grateful for any thoughts.

Are there limit switches in the valve which need to "make" for the boiler
to fire?
Not sure whether the MPVs have these, may depend on manufacturer and
system wiring.

Phil


The synchron motor is faulty. I had the exact same problem a couple of
years ago.

In article ,
"TheScullster" writes:

"CS" wrote

Morning,

I have a conventional CH system with room and hot water thermostats
and a Drayton Mid Position valve, which I recall replacing a good few
years ago. The boiler is not firing when there is demand from the
room stat but it does when there is demand from the water stat. I
think the circuit board in the MPV is faulty, possibly what appears to
be a relay. The synchron motor works and the water valve operates.
Grateful for any thoughts.

Are there limit switches in the valve which need to "make" for the boiler to
fire?
Not sure whether the MPVs have these, may depend on manufacturer and system
wiring.

Yes, there's a microswitch at the full travel position (which is
central heating only). In most circuit arrangements, this microswitch
is used to generate the call for heat signal to the boiler. Most
likely the microswitch has failed, or the MPV isn't making it all
the way across and isn't operating the microswitch.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

In message , slider writes

"TheScullster" wrote in message
news

"CS" wrote

Morning,

I have a conventional CH system with room and hot water thermostats
and a Drayton Mid Position valve, which I recall replacing a good few
years ago. The boiler is not firing when there is demand from the
room stat but it does when there is demand from the water stat. I
think the circuit board in the MPV is faulty, possibly what appears to
be a relay. The synchron motor works and the water valve operates.
Grateful for any thoughts.

Are there limit switches in the valve which need to "make" for the boiler
to fire?
Not sure whether the MPVs have these, may depend on manufacturer and
system wiring.

Phil


The synchron motor is faulty. I had the exact same problem a couple of
years ago.

Not necessarily - could be a burned out microswitch


--
geoff

On Mon, 21 Apr 2008 00:05:31 -0700, CS wrote:

Morning,

I have a conventional CH system with room and hot water thermostats and
a Drayton Mid Position valve, which I recall replacing a good few years
ago. The boiler is not firing when there is demand from the room stat
but it does when there is demand from the water stat. I think the
circuit board in the MPV is faulty, possibly what appears to be a relay.
The synchron motor works and the water valve operates. Grateful for any
thoughts.

TVMIA

The drayton units are the ones that get rebadged as BG/Celsia etc.

They are available from (Wolseley) Parts Centre (amongst other places).

It might be that the valve is not getting to the CH only end position or
the microswitch is fubar.


--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at http://www.diyfaq.org.uk
Gas fitting FAQ http://www.makewrite.demon.co.uk/GasFitting.html
Sealed CH FAQ http://www.makewrite.demon.co.uk/SealedCH.html
Choosing a Boiler FAQ http://www.makewrite.demon.co.uk/BoilerChoice.html